Document 1050EO8vBx2kQJBY5Laa8zgGq

*7 /t / - v- API TOXICOLOGICAL REVIEW BENZENE SECOND EDITION, I960 The information and recommendations contained in this publication have been compiled from tourcea believed to be reliable and to represent the best current opinion on the subject. No warranty, guarantee, or representation is made by the American Petroleum Institute as to the absolute correctness or sufficiency of any representation contained in this and other Toxicological Reviews, and the Institute assumes no responsibility in connection therewith; nor can it be assumed that all acceptable safety measures are contained in this and other Toxicological Reviews, or that other or additional measures may not be required under particular or excep tional conditions or circumstances. The American Petroleum Institute, as sponsor of this review, takes no position as to whether or not any method contained herein it covered by an existing patent, nor as to the validity of any patent alleged to cover any such method. Furthermore, nothing contained in tbit review grants any right, by implication or otherwise, for the manufacture, sale, or use in connection with any method, apparatus, or product covered by letters patent. This review was prepared at the Harvard School of Public Health, Boston, Mass., under the direction of Professor Philip Drinker. Anyone desiring to submit addi tional Information or proposed changes for consideration prior to reissuance of this review is requested to send them to the American Petroleum Institute. AMERICAN PETROLEUM INSTITUTE 1271 Avenue op the Americas New York 20, N. Y. Price 2S Cent* t no CONFIDENTIAL YZ0077431 API TOXICOLOGICAL REVIEW OF BENZENE I. Substance Benzene Formula: C,H Structural formula: Molecular weight: 78.11 Synonyms: benzol phene II. Properties and Characteristics u> 1 * Boiling point =80.1 C (176.2 F) at 760 mm. Melting point - =5.4 C to 5.5 C (41.7 F to 41.9 F). Vapor pressure =74.6 mm of mercury at 20 C (68 F). Liquid density = 0.899 g per milliliter atOC (32 F). Explosive limits = 1.4 to 8 per cent. Flash point = J2 F (closed cup). Refractive index= 1.5016 at 20 C (68 F). Specific gravity =0.8787 at 15 C (59 F). 1 mg per liter =313 ppm; 1 ppm=0.003l9 mg per liter. Benzene is a clear, colorless liquid with a charac teristic pleasant odor at low concentrations and a dis agreeable odor at higher concentrations. It forms a highly flammable and explosive mixture with air at con centrations ranging from 1.4 to 8.0 per cent benzene by volume. Pure benzene bums with a yellow, luminous, smoky flame and is a fire hazard unless proper care is taken in handling and storage. Benzene is relatively insoluble in water (0.08 g in 100 ml of water at 22 C) but is readily miscible In all proportions with alcohol, ether, acetic acid, chloroform, carbon disulfide, carbon tetrachloride, and similar or ganic solvents. Commercial benzene is practically never pure and usually contains vaiying amounts of xylene, phenol, and toluene; commercial benzene also contains traces of carbon disulfide (0.2 to 1.0 per cent), thio phene (0.1 to 0.2 per cent), olefins, naphthalene, and similar substances. Chemically, benzene is the simplest of the aromatic hydrocarbons. It is relatively stable but is capable of a variety of substitution reactions such as chlorination, nitration, sulfonation, and alkylation. Benzene is an ex cellent solvent for most organic substances. " Kieurcs refer to BIBLIOGRAPHY on p. 6. III. Manufacture, Usea, and Possible Sources of Exposure Benzene is usually manufactured from catalytically reformed light naphthas from which it is isolated by distillation or solvent extraction. Benzene is used as a solvent in many applications. It is also used as a component of some motor fuels and as the raw material for the manufacture of a host of syn thetic chemicals. Examples are: styrene, phenol, aniline, DDT, chlorobenzene, cumene, nitrobenzene, diphenyl, cyclohexane, adipic acid, and detergents. Because of its volatility, benzene presents n vapor hazard. The vapor may arise from numerous handling operations, as well as from leaks and accidental spills. Skin contact is a possibility when handling or packaging. IV. Toxicology a. Aeule Effect* Acute benzene poisoning generally results from the inhalation of relatively high concentrations of vapor. Exposure to air containing benzene in concentrations of 19,000 ppm to 20,000 ppm (61 to 65 mg per liter of air) may cause death within 5 to 10 min, whereas con centrations of 7,500 ppm (25 mg per liter) are dan gerous to life in one-half to one hour.* Severe toxic effects may be caused by 1-hour exposure to concen trations of 1,500 ppm (4.8 mg per liter). Concentra tions of 500 ppm (1.6 mg per liter) may lead to symp toms of illness when exposure continues for more than a short time.' Inhalation of 50 ppm to 150 ppm (0.10 to 0.48 mg per liter) of benzene for 5 hours caused slight headache, weariness, and lassitude. The red-blood count de creased, the white-blood count was unchanged except for mild lymphocytosis, eosinopenia, and monocyto penia. The albumin-globulin ratio increased slightly at lower concentrations but decreased with higher con centrations. The urinary coproporphyrins were in creased, whereas the urinary sulfgle ratio was de creased.' Skin contact will cause dehydration and defatting which may lead to dermatitis. Systemic intoxication by cutaneous absorption it unlikely. Drinking benzene causes acute symptoms with local evidence of acute irritation of the mouth, throat, and stomach. A tnblespoonful or less of benzene when swal lowed has been known to cause serious collapse. Subse- ( HO 067885 CONF tdfntial YZ0077432 benzene 3 quently, h may retult in bronchitic r pneumonia which Unquestionably, small amounts of benzene can be ab ii probably caused by benzene entering the air passages.' sorbed through the skin, but it is very doubtful that ( Acute exposure to benzene exerts a toxic action on enough would be absorbed by this route to cause sys sr: the central nervous^systein. Benuane first behaves as a temic poisoning*1 stimulant--in tlie early stages of acute poisoning, per sons show excitement, euphoria, hilarity; then quite sud b. Chraale Effect* denly this changes to weariness, fatigue, and sleepiness, followed by coma and death.* Acute exposure to benzene produces rapidly increas ing symptoms of dizziness, excitation, and pallor, fol lowed by flushing, weakness, headache, breathlessness, constriction in the chest, and fear of impending death. Visual disturbances, tremors, and muscular weakness are also encountered. The victim may lose consciousness and pass into coma or may develop acute mania and de lirium. Convulsions occur frequently. Death may supervene almost at once or several hours to several days following exposure.* Recovery from acute benzene poisoning requires from one to four weeks. Immediately after exposure there are temporary symptoms of chest and head pains, shortness of breath, giddiness, nausea, and loss of ap petite. Evidence of unsteady gait, nervous irritability, Chronic benzene poisoning results from repeated or continuous exposure to relatively low concentrations of benzene vapor. The level and degree of exposure neces sary to produce poisoning vary widely. There are at least two well-authenticated cases of poisoning by re peated exposures to 75 ppm.11 The toxic action is exerted mainly on the hematopoi etic system. It may take months or even years to show harmful effects. Symptoms may be present over long periods, i.e. headaches, dizziness, fatigue, anorexia, and dyspnea. They may be varied and vague and not ob viously connected with benzene poisoning. During the early stages of poisoning, Heinz bodies may be present in the red-blood cells and a neutropenia is often seen. At this stage the blood picture may re turn to normal after removal from contact with benzene. As chronic poisoning progresses, nausea and vomit '* and breathlessness may peraist for two or three weeks, ing, burning sensations of the eyes and throat, and whereas cardiac distress and a peculiar yellow pallor to hemorrhages from mucous membranes, tongue, and the skin may last for as long as a month. Recovery from gums become manifest. Purpuric spots and ecchy- acute poisoning Is generally complete after this period, moses may follow the slightest injury, and epistaxis may ( although evidences of chronic benzene poisoning may occur. Menorrhagia, metrorrhagia, and spontaneous be encountered later.* abortion may develop in otherwise healthy women. Benzene also sensitizes the heart muscle to the action Blood examination at this point may show leukopenia of epinephrine, so that instant death may occur as a (below 4,000 white cells), neutropenia, and a severe result of ventricular fibrillation.1 Muscular activity in creases the rate and severity of acute benzene poisoning. Persons dying of acute benzene poisoning generally show absence of clotting of the blood and widespread pe techial hemorrhages in the brain, pleura, pericardium, urinary tract, intestinal tract, mucous membranes, and skin. There are no specific lesions of diagnostic im portance.* anemia. Later the platelet count falls so that thrombopenia is marked. The blood condition, at this stage, may have become irreversible. The clinical picture of a worker with chronic benzene poisoning at this stage is characteristic--he complains of headaches, giddiness, drowsiness, lassitude, loss of appetite, and nausea with occasional vomiting. He looks pale; is short of breath; has a rapid pulse, a low blood pressure, and a mildly ele Local efTects from acute exposure are seldom severe. vated temperature. He may also have epistaxis, bleeding Continued skin contact with benzene results in defatting from the gums, a purpuric rash, or subconjunctival f the skin and leads to erythema, dry scaling, and, in hemorrhages. The condition progresses slowly to acute some cases, the formation of vesicular papules. Pro leukopenia ending in fatal aplastic anemia.* Repeated longed exposure may produce lesions resembling firstor second-degree burns. It may cause considerable ir small doses of benzene by mouth can produce the same type of chronic poisoning.' ritation of the eyes or mucous membranes of the nose and throat cm contact. Repeated contact of benzene with the skin will cause dehydration and delipidization predisposing t derma titis. Benzene poisoning by skin absorption has received Benzene is relatively insoluble in body fluids and tis scant attention in the literature. The possibility of per sues. Therefore, only small amounts are absorbed by cutaneous absorption of benzene has been studied in the body. Equilibrium between blood and air is ap three cases. Immersion of the hands and forearms from proached within a few minutes after exposure is begun, / 25 to 35 min showed no evidence of skin absorption.1* and practically complete elimination of benzene from the 00 067886 CONFIDENTIAL YZ0077433 4 API TOXICOLOOICAL REVIEW blood occuri within a few minutes after exposure Is ter minated. Higher concentrations of benzene are obtained in tissues with a greater fat content, and saturation and -"elimination are roore-graduaUX Human subjects inhated benzene in concentrations of 340 micrograms per liter of air for 5 hours. Between 33 and 3 per cent of the inhaled benzene was retained (383 mg). During the desaturation period 3.8 to 27.8 per cent of retained benzene was excreted through the lungs and 0.1 to 0.2 per cent in the urine and other body excreta. Of the absorbed benzene, 9.7 to 42 per cent was excreted in the urine as phenol, 0 to 5.4 per cent as pyrocatechol, and 0,1 to 3.3 per cent as hydroquinone. Excretion of phenol and pyrocatechol was highest during the first 24 hours and complete in 48 hours, whereas hydroquinone took more than'48 hours. Excretion of organic sulfates in urine of exposed subjects was in creased. The opinion was expressed that benzene affects the metabolism of proteins, the metabolites of which are excreted in urine as ethereal sulfates.1* Benzene is unique in its myelotoxicity. It has been shown that the introduction of an alkyl group into the aromatic ring results in a loss of its myelotoxic property. This difference may be a result of the difference in the metabolic pathway. Benzene is metabolized to phenols and quinones which inhibit cell production. The in vivo metabolites of alkyl benzenes are alcohols and carboxylic acids resulting from side chain oxidations. These com pounds have a low-order toxicity and are devoid of spe cific cell destructive effects.1* A variety of reactions may be encountered as the re sult of the chronic effect of benzene poisoning. There is little correlation between the degree and duration of ex posure and the severity or nature of the findings in the blood on microscopic examination.1* They may consist of a reduction in red-cell, white-cell, or platelet levels-- in any two of these or in nil three. These changes may develop gradually or suddenly. The blood usually shows a moderate reduction in red cells (below 3.5 million), white cells (below 4,500), and platelets. Blood exami nations for evidence of benzene poisoning should con sist of a complete study of red, white, and platelet frac tions. Progressive changes are more significant than the absolute levels. In anemia caused by benzene, it has been shown that there is a constant increase in scrum iron (average in crease, 213 micrograms) which is associated with a re duction of transferrin (average reduction, 225 micro grams). The iron saturation of transferrin is above normal and is matched by iron saturation of the tissue. The cause of the disturbance of iron metabolism in ben zene poisoning is the failure of the marrow to utilize iron as well as increased intake of iron supplied parentcraliy by transfusion.1* There is some evidence that chronic benzene poisoning produces a blood-clotting defect which is caused by functional and morphological as well as a quantitative alteration of the platelets.11 The marrow cells exhibit a decrease in peroxidase in benzene poisoning. Because benzene inhibits granulocyte maturation, it may act on peroxidase metabolites, or the peroxidase may be used up in detoxifying benzene.1' The bone marrow may be hypoplastic, fairly normal, or hyperplastic in appearance. Abnormal forms r young cells may abound, and leukemia as a result of chronic benzene exposure has been reported. Various individuals differ in their bone marrow response to ben zene--cases with symptoms fairly soon after exposure usually have fewer cells in the marrow, whereas cases de veloping later are more apt to have an increased number of cells In the marrow. It is believed that this represents an early weeding out of those who develop hypoplastic changes, rather than a gradual shift from one type of re sponse to the other." * In a long-term follow-up of chronic benzene poison ing 4,538 cases were studied from 2 to 12 years after cessation of work involving exposure. There has been oniy one fatal case, six cases involving bone marrow changes, and one case of lowered resistance to infec tion.*1 The others were practically well but show varying degrees of neutropenia. Benzene is eliminated from the body via the lungs and the kidneys. In one study C-14 labeled benzene was given orally to rabbits. In 2 days 4$ per cent of the dose was eliminated in the expired air (43 per cent as unchanged benzene and 1.5 per cent as carbon dioxide), and 35 per cent was eliminated as metabolites in urine (23 per cent as phenol, 4.8 per cent as quinol, 2.2 per cent as catechol, 0.3 per cent as hydroxyquinol, 0.5 per cent as L-phenylmercapturic acid, and 1.3 per cent as irans~, rra/u-muoonie acid). Five per cent of the administered radioactivity was found in the tissues occurring mainly as metabolites." Certain factors have been noted which influence in dividual variation in susceptibility to benzene, Over weight individuals are more commonly affected,** and a low-protein, high-fat, low-Vitamin C diet is said to promote the disease. The presence of heart or lung dis ease and liver or kidney damage are believed to pre dispose to the condition," Pregnant women may be more susceptible to benzene poisoning.4 Pathologi cal changes in ovaries, testes, thyroid, and pituitary are attributed to benzene; and changes in women work ers leading to sterility are emphasized." ( v DO 067887 CONFIDENTIAL YZ0077434 BENZENE 3 . Recommended Ltalt of Almoipherle E<pewie 4,000,000, hemoglobin less than 12 g per 100 ml CThe generally recognized maximum acceptable con (80 per cent), blood platelets less than 100,000 per centration for benzene vapor is 25 ppm by volume in cu mm, differential count less than 50 per cent poly r ' " alir' (0.08 mg.per litcr-o^lr) Tftt an S-hourmdoarlplyhoenxu clear-leukocytes, and more than a very few posure/ In Germany the maximum permissible con immature blood cells. The urine sulfate test may be centration to which workers may be exposed is 31.3 ppm used, not as a diagnostic test, but as a measure of the by volume in air (0.1 mg per liter of air).** The Massa degree of the current benzene exposure. It does not chusetts laws have established 25 ppm as a maximum measure the degree of benzene poisoning nor the blood benzene concentration." changes present.1 V. Treatment VII. Preeautlonary Measure* Acute benzene poisoning should be considered an The safety measures necessary for the prevention of benzene poisoning are primarily those designed to pre acute emergency. Remove the victim from further ex vent the inhalation of benzene vapor. Proper ventilation, ' posure at once and call a physician immediately. The local exhaust, and closed systems should be used to patient should be kept uferm and quiet in the recumbent position. If breathing has stopped, artificial respira maintain a concentration below the maximum acceptable tion should be started at once. Oxygen should be administered by a qualified person as long as necessary concentration of 25 ppm by volume in air. AU apparatus and piping should be inspected regularly and sys to maintain the normal color of skin and mucous mem tematically for leakage. When excessive concentrations are unavoidably encountered in operations such as the branes. This may prevent the development of severe pulmonary edema. Stimulants will rarely be necessary cleaning of tank cars, vats, or storage tanks, air masks when adequate oxygenation is maintained.1 and protective clothing should be employed.*1 Employ Care should be taken that rescuers are not also over come by vapors. ees should be fully instructed regarding health hazards which may be present in the handling of benzene and Chronic benzene poisoning is extremely refractory to should immediately report any unusual symptoms or treatment. It is most important that the condition be illness. Clothing wet with benzene should be removed promptly. / diagnosed early and the individual withdrawn from fur* If the hands ate likely to have contact with benzene, ' ther contact with the hydrocarbon. Blood transfusions impervious gloves or protective creams should be are temporarily useful in combating severe anemia. used. Proper ventilation, routine plant inspection, VI. Examination control of benzene air concentration, and periodic medi cal examinations are all of the utmost importance.** The pre-employment examination should include a The concentration of benzene vapor in the air should detailed history, physical examination, chest X-ray, and complete blood count. Workers with organic disease of the heart, lungs, liver, or kidneys should be elimi nated, as should those with a history of previous ben zene intoxication or evidence of an abnormality of the blood or blood-clotting mechanisms.*'* ** Periodic re-examinations should be carried out regu larly, the frequency being determined on the basis of the probable degree of exposure. The examination should include a brief interval history and physical examination, together with a complete blood study. The presence of any of the blood changes described require re-examina tion at least twice at intervals of one week and a thorough study of the working conditions. Unless there is noticeable improvement on re-examination, the worker should be withdrawn from further exposure. be checked regularly in locations where the possibility of excessive exposure may be encountered. This may be done by a variety of procedures among which are the butanone method,1 the mdinitrobenzsne reduction method,* an absorptiometrie method, and a photocolorimetric determination. The latter method in volves the nitration of benzene with Stepanov mix ature which forms mdinitrobenzene. This gives color reaction with acetone in alkaline solutions. Under similar conditions toluene gives a faint violet color. Based on these photocolorimetric methods small quantities of benzene and toluene can be determined in air." More recently a silica gel adsorption method has been reported.** Accurate quantitative study of atmospheric benzene as low as 0.003 mg per ml (0.9 ppm) may be determined by adsorption on acti vated silica gel and ehition with absolute alcohol The The following changes call for re-examination: white- benzene content is then determined spectrophotometri- blood count less than 4,000, red-blood count less than cally according to ASTM Designation D 1017: Method C DO COMpr 67888 rOFNTrA/ YZ0077435 IT 6 API TOXICOLOGICAL REVIEW of Test for Benzene and Toluene by Ultraviolet Spec trophotometry. The range of measurement is 0.003 mg . .10 L28 mg per liter. The mn vickLwpi approximately ~ 98 per cent. There are a number of instruments on the market which measure hydrocarbon air contamination. The presence of more than one hydrocarbon vapor, however, produces erratic results. VIII. Bibliography 1E. Browning, Toxicity of Industrial Organic Solvents, Industrial Health Research Board Report No. 80, London (1937). * M. G. Jacobs, The Analytical Chemistry of Industrial Poisons, Hazards, and Solvents, 399, Interscience Publish ers, Inc., New York (1944). , *C. D. Hodgman and H/N. Holmes, Handbook of Chemistry and Physics, 25th edn, Chemical Rubber Pub lishing Co., Cleveland (1941). * Y. Henderson and H. W. Haggard, Noxious Genes and the Principles of Respiration Influencing Their Action, 164, Chemical Catalog Co., New York (1943). * M. W. Goldblatt, "Research in Industrial Health in the Chemical Industry," Brit. J. Ind. hied, 12 1 (1955). `Genichl Watanabc, Jun Yasbioka, Haruo Hondo, Masao Matouchl, and Takero Sakaguchi, I. Scl. Labour (Japan) 29 70 (1953); from Chem. Abstr. 6051 (1954). * "Threshold Limit Values lor 1959," American Con ference of Governmental Industrial Hygienisti, A.MA. Anh. Ind. Health 20 266 (1959). 1 J. B. Lurie, "Occupational Health Hazards in the Manu facture of Insecticides," S. Afr. Jour. Clin. Sd% 3 212 (1952). * J. L. Svirbely, R. C. Dunn, and W. P. von Oettingen, 'The Acute Toxicity of Vapors of Certain Solvents Contain ing Appreciable Amounts of Benzene and Toluene," J. Ind. Hyg. Toxicol. 25 366 (1943); and "The Chronic Toxicity of Moderate Concentrations of Benzene and Mixtures of Benzene and Its Homologues for Rats and Dogs," J, Ind, Hyg. Toxicol. 26 37 (1944). **G. L. Conca and A. Maltaglioti, "Study On Trans cutaneous Absorption of Benzene," Med. lavoro 46 194 (1955); from Chem. Abstr., 16232 (1955). 11M. Bowditeh and H. B. Elkina, "Chronic Exposure to Bcnzene-I: The Industrial Aspects," J. Ind. Hyg, Toxicol, 21 321 (1939). 11H. H. Schrcnk, W. P. Yant, S. J. Pearce, F. A, Patty, and R. R. Sayers, "Absorption, Distribution, and Elimina tion of Benzene by Body Tissues and Fluids of Dogs Ex posed to Benzene Vapor," J. Ind. Hyg. Toxicol. 23 20 0941). " J. Teteinger, V. Bergerova-Fiserova, and J. Kudrns, "Metabolism of Benzene in Man," Charles Univ. (Prague), Peacovnl Lekarstvt 4 175 (1952); from Chem. Abstr,, 4181 (1955). * H. W. Gerarde, "Toxicological Studies on Hydrocar bons." AMA. Arch. Ind. Health 13 463 (1956). '* L. A. Erf and C. P. Rhoads, "The Hematological Ef fects of Benzene Poisoning," J. Ind, Hyg. Toxicol. 21 421 (1939). * B. Pernis and L. Marco, "Metabolism of Iron in Hemopaihies Due to Benzene," Med. lavoro 46 325 (1955); from Chem. Abstr., 14996 (1955). *r G. Salta, B. Sartaretli, and F. Calaresu, "The Blood Clotting Process in Chronic Benzene Poisoning," hied, lavoro 45 313 (1954); from Chem. Abstr., 11652 (1954). ** V. Prato and G. F. Rublno, "Bone Marrow Peroxidase in Benzene Poisoning," Univ. Turin (Italy) Minerva med. II, 357 (1954); from Chem. Abstr., 5662 (1955). T. B. Mallory, E. A. Gall, and W, J. Biiclcley, "Chronic Exposure to Benzene-Ill: The Pathological Results," J. Ind. Hyg. Toxicol. 2L 356 (1945). **F. H. Hunter, "Chronic Exposure to Benzene-II: The Clinical Effects," J. Ind. Hyg. Toxicol. 21 331 (1939). ,l Karel Rejsek and Maria Rejskova, "Long Term Ob servation of Chronic Benzene Poisoning," Ada Med. Scand. 152 71 (1955). ** D. V. Parke and R. T. Williams, "Studies in Detoxica tion 49, Metabolism of Benzene Containing C1* Ben zene," Biochem. J. 54 231 (1953). " A. Fell, "La benzolisine professionel," Prtsse med, 41 6,129 (1933). ** C. E. A. Winslow, "Summary of the National Safety Council Study of Benzol Poisoning," J. Ind. Hyg. 9 61 (1927). ** J. L. Gulierres de Alles, "Sterility in Laborers Caused by Benzene and Other Solvents" Med y seguridad trabafo 31 4 (1954); from Chem. Abstr., 13556 (1955). " R, W. van Hoesen Korndorffer, "Toxicology of Sol vents," Plastica 4 11 (1951); from Chem. Abstr,, J1I78 (1955). " Mass. Div. of Occup. Hyg. Bull., Maximum Allowable Concentrations (1957). <~- ** Occupation and Health Encyclopedia of Hygiene, Pathology and Social Welfare, International Labor Office, Geneva 1, 228 (1930). **F. I. Berezovskaya, B. E. Reznik, and S. $. Gitis, "Photometric Determination of Benzene and Toluene," Nauch. Zaplskt, Dnepropetrovsk. Gosudarst. Univ. 43 45 (1953); from Chem. Abstr^ 783 (1955). "Per Ovrum, Determination of Atmospheric Benzene Concentration by Displacement Following Adsorption on Silica Gel," Brit. J. Ind. Med. 13 210 (1R56). - ( 2--mo DO 067889 CONFIDENTIAL YZ0077436 API TOXICOLOGICAL REVIEWS " second Edition Benzene (1960) ................................................................................................... $ .25 Butadiene (1959)................................................................................................. .25 Copper Naphthenate (1959)...................................................................................... 25 Naphthalene (1959)............................................................................................. .25 Naphthenic Acids (1959).................................................................................... .25 TolueneX1960) ..........................................................................................................25 Xylene (1960) ...................................................................................................... 35 YZ0077437 c< AT THE MARCH 3, 1981/ PUBLIC HEARING TEXAS CHEMICAL COUNCIL TESTIMONY ON ETA'S PROPOSED NEW SOURCE PERFORMANCE - -------- STANDARDS FOR VOLATXLB -ORGANIC COMPOUND FUGITIVE EMISSION SOURCES My name is A. H. Nickolaus and I represent the Texas Chemical Council (TCC). The TCC is an association of 87 chemical compani s having more than 67,000 employees and representing approximately 90% of the chemical industry in Texas. Since over half of the nation's petrochemicals are produced by member companies operating in Texas, the proposed regulation is of vital concern to us. r The Texas Chemical Council has joined with the Chemical Manufacturers Association (CMA) in the preparation of detailed comm nts on the proposed regulation, and our combined written comments will be submitted prior to April 6, 1981. Today, I would like to highlight some of our concerns about this standard. A. Definition Of Modification First, to start off on a positive note, at our request the EPA has added an annual allowance of up to 5 1/2% for "process improvements" so that small, routine changes made to an existing process unit will not in themselves subject it to the new source standards. We thank the EPA for this consideration. B. Performance Versus Equipment Standards, Etc. When dealing with facilities broader than a specific process or installation, the TCC believes the EPA should set both a performance standard and an equivalent equipment or work-practice standard. If a performance standard is not possible, then at least an equipment and an equivalent work-practice should be set. This would allow the Synthetic Organic chemicals Manufacturing Industry (SOCMI) the flexibility necessary to design and implement the most efficient and cost effective compliance program. The EPA has failed to do this for pumps, compressors, and valves in the proposed standard; although the TCC believes it is feasible to do so. 1. Pumps (t Compressors For both pumps and compressors, the EPA states in the preambl to this regulation (FR p. 1143 & 1144, Jan. 5, 1981) that a performance standard is not feasible because the application of measurement technology is technologically impractical. Yet in the January 1981 Preliminary Draft Control Technique Guideline for "Control of Volatile Organic Fugitive Emissions from Synthetic Organic Chemical, Polymer, and Resin Manufacturing Equipment", they specify measurement of emissi ns from these pieces as the means of determining compliance. 06789J CONFTDf-NTTAl YZ0028967 cc -2- f The TCC recommends and requests that _a similar monitoring 'option forpumpv anZTcompressors be added to this standard. 2. Valves In Gas & Light-Liquid Service Contrary to the EPA's opinion, the TCC believes that a performance standard for valves in gas and light-liquid service is feasible. Snee and Kittleman of Du Pont have shown (Letter from T. A. Kittleman, Du Pont, to Glynda E. Willins. Radian Corporation, November 13, 1980) that a leak level of 2% is equivalent to the basis UBed by the EPA in the BID to estimate the leak reduction effectiveness of the proposed regulation. i The TCC recommends that the EPA specify 2% of valves leaking as a "good performance" level that is equivalent to the prescribed monitoring program. C. Emissions Abatement The proposed standard requires that emissions be transported through a "closed vent system" to an "enclosed combustion device" or vapor recovery system and then defines an "enclosed combustion device" so as to exclude flares. We take particular exception to this. The TCC in our June 30, 1980, comments to the EPA on the Draft BID provided data showing 99+% efficiencies for a properly designed flare system. The EPA has taken a position, without any data, that flares may be only 60% efficient and that the burden of proof of better is on the SOCMI, We disagree. We have provided necessary data which should not be rejected arbitrarily. Further, since flares are standard abatement devices of long standing in both the chemical and petroleum-refining industries, we believe the burden of proof, with data, is on the EPA. The SOCMI has a heavy investment in flares and will strongly resist EPA's position that they are not acceptable emission control devices. We recommend that the definition of "closed vent system" be modified as follows: "Closed Vent System means a system which is not open to the atmosphere and which is composed of piping, connections, and, if necessary, flow inducing devices that transport gas or vapor from fugitive emission sources to a device which provides 95% abatement or to an enclosed combustion device, vapor recovery system, properly designed flare system, or an equivalent control device as determined by paragraph 60.484." D. Monitoring Frequency The rational approach to how frequently monitoring for leaking valves should be performed (60.482f) would be based on a cost- ffective analysis of leak occurrence and recurrence data. The EPA DO 06789? CONFIDENTIAL.. YZ0028968 cC 3 has not done this. Instead, in the preamble {PR p. 1146, Jan. 5, 1981) they state clearly their-basic .commitment to a.jnonthly monitoring schedule '-''apparently as an article of faith. In the BID the EPA has assumed an occurrence frequency biased to favor a monthly program (see attached Figure 1). In the absence of definitive data, the TCC finds it difficult to justify anything but the assumption of a linear leak occurrence with time. Using a linear relationship, a quart rly monitoring frequency giveB the same results as the EPA claims for their monthly program (again see Figure 1). The TCC has and continues to recommend that the required data be obtained and that a rational analysis of monitoring requirements be made. Until that time, the TCC believes the data in the BID cannot justify anythin? more frequent than quarterly monitoring. The TCC recommends that monitoring requirements in the propos d standard be changed to a true quarterly frequency. E. Leak Definition As the EPA has correctly pointed out, most leakage comes from only a few valves, and the problem is to find and repair these. The EPA has proposed 10,000 ppmv as the definition of a leak. Recent EPA data show variations of nearly an order of magnitude in repeat measurements of leak rates on the same valve. For this and other r asons more fully developed in our written comments, the TCC again recommends that a leak be defined as 20,000 ppmv or greater. Th 1 akage reduction attained will be essentially the same as at the 10,000 ppmv cut-off; but maintenance will be reduced by up to 30% as less maintenance effort will be spent on valves with inconsequential 1 ak rates. F. Alternative Standards We commend the EPA for providing in paragraph 60.483 provisions for alternative standards. But in terms of monitoring programs, what the EPA giveth with one hand it taketh away with two. The problem is that an allowable percentage of valves leaking must be determined after the plant is built. Quality control experience shows that quality must be built into a product; it cannot be inspected in. Thus, the time to assure a low-leakage plant is in th original design before the plant is built. But a plant providing the best leak prevention options would have to meet a much lower allowable percentage valves than one not so well designed, and consequently, it would have much less opportunity for a reduc d monitoring program than a poorly designed plant. This doesn't make s nse; low-leak plants should require less inspection - high-leak plants more. DO 067893 conftdfntial YZ0028969 cC 4 What is needed is an incentive for owners to build low-leak plants. Some assurance of an opportunity for reduced monitoring requirements in -such plants -weulA-provide this. In our written comments (60.463c Good Perfttz'hiariTe Incentive), we detail a statistical monitoring plan which results in reduced monitoring requirements for those who me t a "good performance" level equivalent to the BID basis. The TCC strongly advocates the adoption of this proposal. Th advantages of a quality control approach is (1) greater emission reductions will be realized industry-wide because there is an Incentive to do so, (2) the monitoring burden will be lessened on low-leak plants and increased on high-leak ones, and (3) well defin d rules on what can and cannot be done will be available to the owner at the design stage. G. Determination Of Equivalence (60.484) Although the TCC believes guidelines for approval of equivalent r alternate means of emission limitation should be specific so that, having met them, approval by the EPA Regional Offices is more or 1 ss authomatic; the proposed paragraph 60.484 seems to be overly detailed without accomplishing this purpose. The procedure in Subpart Xa, paragraph 60.114a for Standards of Performance for Storage Vessels for Petroleum Liquids Constructed After May 18, 1978, is simpler, more straight forward, and we prefer it to the present proposal. H. Reporting, Recordkeeping, Etc. The TCC believes that the proposed tagging, recordkeeping, and reporting is excessive and goes beyond that necessary to implement the required program and also beyond that required for compliance. In our written comments, we make detailed recommendations to correct this. I. Need t Costs In closing, whether it is legally appropriate or not, we cannot resist again stating our belief that this regulation is unnecessary and that the costs have been under-estimated. We re-affirm the comments we made to the EPA on June 30, 1980, and we recommend them to your attention. Finally, on costs the EPA is still basing monitoring costs on two man-minutes per source despite their own data in Table C4 of th BID showing it took highly motivated contract workers an average of 3.4 minutes to perform this task. AHN/rtg 2-20-81 Q0 067894 confidential YZ0028970 BEFORE THE ENVIRONMENTAL PROTECTION AGENCY COMMENTS OF TEE CHEMICAL MANUFACTURERS ASSOCIATION TVkAJ CfftfMOfNCAl COUNCIL EPA'S PROPOSED RULEMAXING OF NEW SOURCE PERFORMANCE STANDARDS FOR VOLATILE ORGANIC COMPOUND FUGITIVE EMISSION SOURCES UNDER THE CLEAN AIR ACT Proposed Standards of Perfomance ) for New Stationary Sources; VOC ) Fugitive Emission Sources; Synthetic ) Organic Chemicals Manufacturing Industry. 46 Federal Register 1136 (January 6, I9tfl) ) ) ' ) DOCKET NO.A-79-32 ) Geraldine V. Cox. Ph. D. Vice President and Technical Director Janet S. Matey Manager, Air Programs Edmund B. Frost Vice President and General Counsel David W. Carroll Assistant General Counsel April 6, 1981 Chemical Manufacturers Association. Inc. 2501 M Street. N.W. Washington, D.C. 20037 (202) 887-1100 OO 067895 CONFIDENTIAL YZ0028463 S5P.480(C) In earlier drafts to subject proposal regulations, a problem was surfacad viuiT'ttie definition of modification as sat forth in 40 CFS 560.14 as it might apply to fugitive amissions. A concern was ex pressed that continuing small changes routinely made to a process uniu made for a variety of reasons might subject the entire existing unit to the NSPS fugitive emissions requirements. The Agency's prjT>oeed...660.4S0<c^M satisfactorily resolves fehia-earlier -poncera. w understand the Agencies' proposal in 60.460(c) to mean that process improvements, as defined in 60.481, costing up to 5 1/26 annually of th original investment in the affected SOCMI facility shall not by itself be considered a modification. This would satisfactorily resolve our earlier concern. 560.481 -- "Closed Vent System'*. In discussions with EPA's OAQPS staff we were led to believe that the regulations would not prelude safety valve emergency releases to flaring systems or the atmosphere. In this regard, the preamble at page 1140 attempted to clarify that closed vent systems can be used to transport relief valve discharges and fugitive emissions to a control device, such as a flare. The proposed regulations, however. DO 067896 CONFIDENTIAL YZ0028464 These comments are also submitted on behalf the Texas Chemical Council (TCC) whose offices are located at 1000 Brazos Street, Austin, Texas 78701, The TCC is an association of 87 chemical companies having mcra than 67,000 employees an& representing approximately 901 of the chemical industry in Texas, bike the CMA, the TCC has also worked with the E?A over the past several years in the furtherance of responsible environmental regulation. The TCC also I requests that the comments made by them which are referenced in Appendix A of the EPA's "VOC Fugitive Emissions in Synthetic Organic Chemicals Manufacturing Industry - Background Information for Proposed Standards" be incorporated as part of the administrative record in this matter. . The comments we are submitting today make certain recommendations that attempt to clarify, and/or modify the Agency's proposed regulatory program to make technically more sound several substantive provisions, and to simplify procedures, recordkeeping, and reporting where the proposed requirements are either redundant, unnecessary, to demon strate compliance with applicable control requirements, and/or would reduce the paper workload. Nevertheless, we believe that the Agency has made significant progress in addressing many of the concerns raised by CMA in our earlier submittals to the Agency on earlier drafts of the subject pro posal, and on various other Clean Air Act fugitive emissions programs, we believe, however, that additional modifications are still necessary in order to achieve a viable and reasonable technical fugitive emissions * .program.. DO 0**897 confidential i YZ0028465 3a. <L 560.481 -- "Fugitive Saission Source." The definition of "fugitive emission source" includes compressors "efid pumps. Onfoftritely the Agency has not included e definition as to the types of pumps and compressors not subject to the fugitive emissions NSPS requirements. As a result of this apparent oversight reciprocating pumps and compressors are included in the regulatory program. The potential problem we have with the inclusion of recip rocating pumps and compressors are their inability to accommodate double teals or any type of seal that EPA may utlimately raquire. Accordingly, we recommend that in ordar for SPA to avoid scaling problems associatsd with reciprocating pumps and compressors that such pumps and compressors ba expressly excluded from the definition of "fugitive emission source." 560.482 (s) (1) - "dual mechanical seals" As wa have commented on several times in the past, it is in* . appropriats to raquire use of dual mechanical seals for pumps. We- r commend that SPA caaae using the term "mechanical" and merely define the seals to be used in pumps as dual seals. Such s modificati n would provide industry with soma flexibility for a source to use any properly designed dual seal. This modification would allow ` for the use of either pressure or level control devices. We compliment the Agency on adopting an equivalency regulation in 560.484(b) that will allow companies to demonstrate the equival nc cf single seals where adequate and permanent monitoring will result in equivalent degree of controls. 00 067898 OONFTDFNTIai YZ0028466 3- limit closed v nt systems to transporting mergency releases tc an enclosed combustion device or vapor recovery system. -- ' We are. concorned'*bat-the clear language of the proposed regu lations contradicts statements made by EPA's OAQFS, the preamble, and various support documents that emergency releases can be transported by a closed vent system to not only an enclosed combustion device and vapor recovery system, as well as, a properly designed flare system, nd other equivalent control devices. Failure to correct this inconsistency and 'revise the regulatory language could result in unanticipated enforcement initiatives based on the language of the proposed regulations. In addition, failure to revise the definition of closed vent system would arbitrarily exclude other control devices and properly designed flare systems which in many instances can achieve or approach the same degree of hydrocarbon reduction as en closed combustion devices or vapor recovery system at significantly lower costs. In order to clarify this matter we would recommend that the d - fir.ition of "closed vent system" be modified, as follows: "Closed Vent System" means a system which is not open to the atmosphere and which is composed of piping, connections, and, if necessary, flow in- ducing devices that transport gas or vapor from a fugitive emission source to an inclosed combustion device, vapor recovery system, a properly designed flare system, or an equivalent control device as determined by $60,484. 00 067899 CONFrDETNTIAl In this regard we wish to reaffirm the position taken and made in th Texas Chemical Council's letter f 30 June 1980 to the EPA (comments on the Draft BID and Recommended 50CNI Standard) regarding flares and their use. - YZ0028467 in rder t remedy this inconsistency. As ws discussed shove, we believe that s closed vent system sh uld >e-defined.generally enough so that VOC fugitive, emissions can be transported to appropriately designed enclosed combustion devices, vapor recovery systems, as well as, properly designed flare systems, or an equivalent control device. As presently drafted, fugitive emissions from pumps would be initially precluded from being controlled by catalytic combustion units unless a time consuming and costly equivalency demonstration can be made. Several of our member companies indicate that such control devices achieve equal or better control than the two systems presently reoognized'in S60.4B2 (a) (3) (ii). To preclude catalytic combustion units without an adequate justification by EPA for requiring equivalency demonstration would have to be characterized as an arbritrary action. The comments set forth above are equally applicable to pumps fugitive emissions regulated under 560.482(a)(7). Ws would hope that appropriate modifications consistent with a revised definition of closed vent system would be incorporated by EPA in the final version of 5560.482(a) (3) (ii) and (a)(7). 560.482(a)(6) - delayed compliance The proposed regulation requires that a leaX be repaired as s on as practicable, but not later than 15 days after its detected,'except as provided in 560.482(h). The exception allows extensions only where the repair is technically infeasible without a complete or partial process unit shutdown. The extension, however, cannot exceed the process unit shutdown. The instant delay of compliance provision significantly improves n arlier drafts which imposed arbitrary deadlines and meaningless reporting requirements. We, nev rtheless, hav s veral r commendations DO 067900 CONFIDENTIAL YZ0028468 60.482(a) (4) LIquid Leak* This- paragraph" defines liquid dripping from a pump seal a a laak. However, the barrier fluid could be water so there would be no reason to repair a seal operated per 60.4B2(a)(3)(i) where the barrier fluid pressure is higher than the pump pressure so long as this higher pressure is maintained. We recommend that this paragraph be reworded to sayi "Each pump shall be checked by visual inspection each calendar weik for indications of liquids dripping from the pump seal. If indications of liquids dripping from the pump are seen, the vapor emissions shall be monitored .by the methods specified in 60.485. A vapor concentration greater than 200 ppm above background shall constitute a leak." 560.482 (a) C3) (ii) and fa) (7) - "residence tine." In our review of this section we noticed an inconsistency between the proposed residence time and the technical data on residence time set forth at page 4-18 of the technical support document. See VOC Fugitive Emissions in Synthetic Organic Chemicals Manufacturing Industry - Background Information for Proposed Standards, EPA-450/3-80-033a, at 4-18 (November 1980). An appropriate modifi cation of this requirement in the final regulations is necessary DO 067901 I CONFIDENTIAL YZ0028469 7- special order and taka up to ona ytar f r dalivary), and/or unforseen manufacturers and/or dalivary delays (e.g., strikes, fires, raw materiel d*laya_Jji 4filivary)*, Any one or a combination of the above scenarios would result in the necessary replacement part(s) not be available until after the next scheduled shutdown. Since the proposed regulations would make continued operati n after such a shutdown a violation of the Clean Air Act, we strongly recommend that a limited extension provision be Incorporated by EPA into the regulations. We envision.placing the burden of requesting such a request upon industry by requiring a formal submittal to EPA in which the source would have to justify the need for the further delay in repair and the projected time frame for achieving compliance. We recommend that $60,482 (h) be amended to Include the following r gu- latory language: "Delay of repair will be allowed beyond a process unit shutdown only where and for the period of time a source demonstrates to the satisfaction of the Regional Administrator or delegatee that repair of a leak by replacing physical equipment by replacing physical equipment exceeded the normal stock of spare parts and cannot be delivered until after the next shutdown, a special order of a part is required and cannot be delivered until after the next shutdown, and/or because of unforseen manu facturers and/or delivery delays, the replacement parts cannot be delivered until after the next shutdown." The consequences of not including such a provision in the final r gu- lati ns uld r suit in unanticipated and costly continuan s f a shutdown until the repair parts are obtained, r in the exposure ------------------------- DO 067902 CONFrOFNTTAI YZ0028470 6- which would further clarify tha regulati ns and nor accurately re flect r al world peratlona. ___ first* wa would recommend a definition of what situations qualify as technically infeasible in order to be accorded an extension aftar the initial 15 day compliance period. 8uch a clarification would minimize uncertainties and would reduce any unwarranted enforcement proceedings resulting where such an ambiquity in the regulations. Accordingly, we recommend that $60,482 (h) be revised to Include a definition of technical infeasibility* as followst "For purposes of 660.482(h)* technically infeasible shall mean where a repair within 15 days of leak detection would constitute an unsafe practice, oould result in premature total process failure, or could cause an unscheduled complete or partial process until shutdown." The second part of our recommendation on delayed compliance concerns the agency requirement that all repairs may not be delayed under any circumstances beyond a process unit shutdown. We concur that many*' f the remaining delayed repair actions will be remedied during a shutdown where repair actions can not ba technically of safety be conducted while the process unit is in operation. As tha Agency is aware* most schedule shutdowns are on an annual basis or baaed upon operating performance of the process unit. As a result, there may be some limited instances where replacement of leaking equipment may not be available until after the shutdown is completed. Such instan es include (but are not all inclusive) abnormal near term demands for r placement parts that exceed the quantity of replacement parts that ar normally maintained in stock end can not be replaced on short notice* the replacement parts/equipment era not off tha shelf items , and require long lead time for d livery (i.e., soma pumps r quire DO 067903 ------------ CONFTDFNTTAL YZ0028471 ---------------------------------------- -J-. the pr csss unit w uld bs greater than ths missions fr m ths fugitive amission s urce(s)." Ws believe such a r vision would remedy an unnecessarily narrow and environmentally counterproductive requirement. 560.482tbf'-^Compressor Standards. As a general comment, the comments, issues, and recommendati ns we raised on pump standards are generally equally applicable to c r pressors. We do want to point out one inconsistency in the compressor standards which we believe should be clarified. Xn $60.482(b)(1) and (3) we are happy to jnote that the Agency only requires a seal system with c rtain characteristics be used for all compressors. Ibis requirement would be consistent with our comment on $$60,482 (a) (1) end (3) d aling with pumps, in which we objected to the Agency's requiring dual mechanical seals and not providing the necessary flexibility with a * dual seal system requirement. The inconsistency exists because the Agency at $60.482(b)(4) then reverts to referring to dual mechanical s al systems. Our substantive comments on $$60,482 (b) (3) (ii) and (b) are r fie ted in our comments on $$60,482 (a) C3) (ii) and (a)(2) above. Our substantive coimaents on $60,482 (b) (5) and its interrelati nship with 560.482(h) are reflected in our comments on $60.482(a)(6) abov . finally, our substantive comments on $60,482(b)(8) are reflected in our comments on $60.482(a)(9) above. $60.482(c)(5) - safety/relief valves in gat/vapor service. As proposed, the section requires each safety/relief valve t return to emitting less than 200ppm above background after an emergency Pr ssure release no later than five calendar days after each episode of pressure release. As proposed the regulation leaves a tremendous loophole which had to be an oversight. Zf a process unit is down five days after the release, it by definition will be in compliance. DO 067904 , _________________________ CONFIDENTIAL YZ0028472 t aignifi ant riminal and civil panaltias for r Burning perati n without rapairing all laakt. Wo would nsidar it an arbitrary . and papricioua actiojof tha Administrator to not provide auch a A**'-* IMh-- remedy whara tha aourca haa actad in good faith to rapair all re maining leaks at tha naxt achadulad ahutdown, but aolaly bacauaa of uncontrollable evanta tha nacaaaary rapair parte era not available. $60.482 (a) (9) - "Operation of Control Syetama." This proviaion aaaantially requirea that all axiating propoa d fugitive emission control systems be operated at all tinea VOC emissions nay occur. We are concerned that a coneervative and narrow reading of this proviaion will aaaantially preclude a proceaa unite op ration where expected or.unexpected maintenance of tha control ayetem ia required, or an emergency requiree tha control ayatam to go down for repaira. It maker little aanaa to require the entir pro- c aa unit to ahutdown whara the control ayatam haa to go out of aarvica for a ahort period of time to conduct maintenance and/or c rrect an emergency condition. In fact the start-up and ahutdown f the proceaa unit in moat inatancaa will probably raault in greater emiaaiona of VOC than if tha proceaa unit continued operation for the ahort period of time until tha amiaaion control ayatam ia back on line. Ha recommend that thin proviaion be modified to aaaantially allow a by-pass of VOC emiaaiona where tha control eyetema muat be taken ut of aarvica for maintenance or an emergency only whara the net VOC emiaaiona that will be bypaared would not exceed tha axcaaa emiaaiona that would raault from a ahutdown and start-up of tha proceaa unit. W recommend that $60,482 (a) (9} be raviaed to added a aacond aentence, aa followa t "A a urea, howav r, may bypaaa tha applicable control device aat forth in $60.482(a)(3)tii) and (iii) where miaai na fr m an aaaociatad ahutdown and atartup f I DO 067905 CONFIDENT TA! YZ0028473 $60,462 (d) (2) to rev: id, a* follow*! "(2) Each clo*d purge system as required toy $60.482(d)(1) shell return the purged process fluid directly to the process line, or shell collect the purged prooess fluid for recycle or disposel toy meens of e closed vent system." The techhtcel support document does not support the proposed regu lations . Unless e modification is made, the Administrators actions must toe characterised as arbitrary and capricious. $60.462(f)(2} - "definition of valve leak* The SPA has proposed 10,000 ppmv as the definition of a leak. In addition to being the same action level si set forth in the refln ry CTG, we understand from a July 17, 1980, SPA meeting with the TCC that this particular level was also chosen because it is the top of the scale on the Century Volatile Organic Analyser. Apparently SPA felt 10,000 ppmv would make compliance easier for the chemical industry. We havs some significant disagreements with these underlying assumpti ns. We believe a higher trigger level would achieve essentially the same control with much improved maintenance efficiency. The ecale on the Century GC is a minor consideration. Headings higher than 10,000 can be obtained readily with a dilution apparatus. In addition, we are confident that equipment manufacturers will be able to supply instruments with direct reading scales to whatever level we require. As the EPA has correctly pointed out, most of the leakage comes from only a few valves and the problem is to locate and repair thas . Based on the refinery data, about 9B% of the emissions from valves in gas/vapor service will be from those having leak concentrations graster than 10,000 ppmv. Similarly, about 971 of the emissions will c me from valves with screening values above 20,000 ppmv (Pig. 4-7A, EPA 600/2-79-044, "Emission Factors and Frequency of Leek Occurrence For Fittings in Refinery Process Units"). in a previous letter to DO 067906 CONFIDENTIAL YZ0028474 10 We assume EPA meant five celender days r m resumption f n rmal opara ti ns after each episode of pressure release. ^-- We-wapt to commend- the Agency for establishing a performance standard for safety/relief valves in gas/vapor service rather than specifying inflexible design standards. We would encourage the Agency to rethink the proposed pump and compressor standards to establish a performance standard for pumps and compressors (i.e., 10,000ppm). It is our view that a performance standard is more a simplistic regulatory program to implement and provides necessary flexibility for sources t install the most oost-efficient and effective emission controls and process systems. S60.4B2(d)(2) - sampling systems. As proposed the regulation limits the means of disposing of process missions. The proposal provides the option of returning the fluid directly to the process line, or in the alternative, collecting the purged process fluid for recycle or disposal without VOC emissions to the atmosphere. This requirement amounts to a sero emissions require ment. As a fundamental conoept the closed loop sampling system may be inappropriate or technically Infeasible (i.e., low pressure process or tankage, safety requirements). Accordingly, this would require a collection system be used with no emission allowed. We note that no support for this premise is provided in the Agency's technical support document (see 4-22 to 23). Zn fact, the support document mentions that such fluids could be directed to a control device such as a properly d signed flare. In light of the lack of technical support for the proposed regulation, we recommend that the Agency include the use of closed vent systems to minimise emissions from sampling systems. We recommend that j j j j ' i DO 067907 CONF J DPNTI Al i YZ0028475 -13- 160.4B2(f)(3) - "monit ring frequency* The proposal essentially requir s that monit ring pr gran for**N * valves be on a monthly basis for leakers and quarterly basis for non- j leakers. Ve strongly endorse this proposal and caution against s r treating to mandating monthly monitoring. r"h/> One rationale the Agency might consider for requiring monthly \ monitoring is a reliance on refinery fugitive emissions data where the \ Agency ultimately required monthly monitoring. The leak frequency data developed by EPA for the chemical industry are MOT similar to the refining data as EPA indicates on page 1141 of the proposal. Die differences are summarised, as follows: Source Type _______________________________________ Difference in leak frequ ncy between SOCMX and refining data. Valves Gas service Light liquid service Heavy liquid service Similar SOCMX 50% of refining Similar Punps Light liquid Heavy liquid SOCMX 33% of refining Similar Compressors SOCMX>21% of refining Relief Valves SOCMX745I of refining Process Drains Similar Flanges Higher ISg? Attachment B ( C for greater detail and discussion on this issue.) The above differences do not account for the fact that the chemical industry studies were conducted using a Century OVA-108 instrument calibrated on methane while the refining studies were c n- ducted using a Bacharach TLV instrument calibrated on hexane. Studi s by Exxon Chemical (see Attachment D) on both instruments using both calibration gases show that 29 percent more leaks are found using the i DO 067908 CONriDFNTTAl YZ0028476 -12- the Agency, (eee Attachment A) the TCC ha* ahown that using a 20,000 ppnv -- action..level versus J^O ,000 results in only 1% more emissions but reduces maintenance costa by 301. This factor is of major significance since S ction 111 requires the Administrator to take into consideration the cost of achieving continuous emission reductions. In S60.48^(a) (4) (il) methane at 10,000 ppmv is specified as the calibration gas. This requirement differs from the refinery data on which most of tfc* technical support is based where hexane was used for this purpose.- A study of the relative response of various gas s with respect to methane and hexane indicates that a methane calibration will, in effect, lower the trigger point to about 0,000 ppm with th C ntury GC and even lower with the Bacharach TLV meter. This means more maintenance effort will be spent on valves with inconsequential 1 ak rates. Recent data (Problem-Oriented Report, "Frequency of Leak Occurrence for fittings in Synthetic Organic Chemical Plant Process Units", SPA, Sept. 1980, DCN 80-231-372-05-35, Data Listing For SPA Project 168-03-2776, Radian Corporation, December 19, 1980) from EPA's studi s on leak occurence and recurrence in the SOCHI show a wide variability in repeat screening values for the same source. For exainple in k Figure 4-3 of the Problem-Oriented Report^on th* second day^values of approximately 2000, 6000 and 15000 were obtained from repeat measur ments n the same valve. It is important that maintenance efforts be spent n the large leakers and not on the small ones since some data indicate that attempts to repair these only made matters worse. Thus the trigger point should be set high enough to insure isolating only the bad 1 akers. F r these reasons - maintenance efficiency, the effect of Inethane calibration, and me surement variability, we again recommend that a 1 ak b defin d at 160.482(f)(2) as 20,000 ppmv r gr ater. I D0 067go9 confidential YZ0028477 15- TCC recommend* using a linear 1 k rscurrsnc* rata with tint in the, absence f data. Second the assunpti n that all the source types will * have a uniform recurrence rate (201 per year) is not a logical assump- tion nor is it supported by the record. In the absence of data, a more logical assumption is that recurrence will vary in proporti n to occurenee. EPA, given the lack of data on valve leak recurrence and ccurence with time, has structured a monitoring program for valv s as gas/vapor aijd light liquid service which calls for monthly monitoring for leakers and quarterly monitoring for non-leakers. EPA states that straight monthly monitoring for all valves may be required if r currence is found to be important. Ye submit that the existing chemical industry data shows initial occurence to be less (by 50% in the case of light liquid valves) than the the refinery data. Because of this difference, we recommend that EPA require the monthly monitoring schema only r those owner operators desiring to show equivalence demonstration. Since EPA has acknowledged that limited data are available on ccurence/recurrence, we submit that EPA can only reserve the right to require more frequent monitoring whan the data are available from those owner operators desiring equivalence. 50.482 (f) (4)' - delayed compliance. Our substantive comments on this section and its interrelation ship with 60.482Ch] are reflected in our comments on 60.482Ca)(6) above. 60.482 (f) (7) - Accessibility Exclusion. As we reviewed1 the prepesadsegulations, we identified an area dealing-primarily with.asodifled eeusees that will he subjest te-ahe nm" -**""**"*" r V" ----a. -in-the proposed regulations; As the Agency is well sward, at-older facilities many valves axt nut mutinelj accessible because .of "Safe*y __ _________________________________________________ DO 067910 CONFIDENTIAL YZ0028478 Century calibrated on math ne a* compared t the Bacharach calibrated on hexane. Thus th 60CMI Data ie probably even lest than the re fining data as ehown above. SincV the~above data show initial leak occurence frequency within the chemical Industry to be less than the refining sector, we feel that EPA should require only true quarterly monitoring. Ne are f the pinion that the lower leak occurence frequency within 80CMI wi,ll more than offset the, admittedly, unknown effects of leak recurrence. EPA has offerred as a reason for possibly requiring monthly monitoring to be the potential importance of leak recurrence between valve monit ring intervals. . This analysis was performed without the benefit of review f EPA's chemical industry valve maintenance study which may provide further information on the importance of valve leak recurrence. The above conclusions are discussed in further detail below and in the attachments. The EPA continues to base occurence and recurrence leak rate assumptions on Table 4-2 from the final technical support document (copy attached as Attachment E) which is the same as taken from the draft technical support document. The Texas Chemical Council (TCC) c nmented on the issue of occurence/recurrence in comments submitt d to EPA in June of 1980. These comments have not been addressed by EPA and cannot be ignored, we wish to emphasise the points raised in TCC's comments on this issue are still valid. In addition to TCC's arlier comments, we offer the following additional comments. First, EPA's assumption of non linear leak recurrence with time is not based on any data but rather an "engineering judgment". The assumption that twice as many leaks will be found annually as compar d t quarterly and twice as. many leaks will be found quarterly as compared to monthly is simply n t logical and is n t supported by the r cord. _________ ' DO 067911 conf tofnt TAt ' VZ0028479 / < As the Agency is well aware, in existing facilities many valves are not routinely accessible because of elevation or because access to the valve-bonnet,ir;*esticted, etc. Most, if not- all of these, can be eliminated in an entirely new plant. But they become a problem in ar. older plant that becomes subject to this regulation because of modification. To correct these problems, we propose valves that are inaccessible for safety reasons and that valves that are Inaccessible for other reasons in modified sources be excluded from the requirement of 60.482(f)(1)-(6) but subject to the new 60.482(f)<7)-<8). Accordingly, we recommend that the new 60.482(f)(7) and 60.482(f)(8) be added as follows: "(7) (i) An owner or operator of a new or modified source subject to the requirements of 60.482(f)(l)-(6) may for valves that are routinely inaccessible for safety reasons monitor each inaccessible valve for leaks after a process unit overhaul prior to startup by pressuring with nitrogen to the system process pressure or 100 psig, whichever is less, and checking with a soap solution for bubbles, or other equivalent test method pursuant to 60.484." "(ii) When a leak is detected, it shall be repaired as soon as practicable, but no later than the next scheduled shutdown, or consistent with 60.482(h)." "(iii) For purposes of 483 or 484, inaccessible valves shall not be included." DO 0679'? CONF'OFNT'I L YZ0028480 -16- eor.s-iderations. '7 'v. / We propose that valves, at modifisd facilities subject to these requirement*#. that are inaccessible for safety reaaona be excluded from the requirments of $$60,482 (f) (1)-(6) but subject to a new $60,482 (f) (7), Thirnew provision would only apply to modified sources and not apply to new facilities. Accordingly, we recommend that a new $60,482 (f) (7) be'added# as follows: N. / "(i) An owner or operator of a modified source subject to the requirements of SS60.482.Cfc) ID*(6) # may for valves# that are routinely in^cessible for safety reasons# monitor earh inaccessible vale for leaks after a process unit/overhaul prior to start-up by pressuring with nitrogen the system process pressure# or 100 psi# whichever is less# and checking with a soap solution for bubbles# or other equivalent test method^ pursuant to $60,484." "Cii) When a leak is dejvlcted# it shall be repaired as soon as practicable^ but no later than the next scheduled shutdovmXor consistent with 560.482(h). "(iii) TorjHrfposes of $$483 or 484, inaccessible ^ valve s^ahrfll not be included." As we reviewed the proposed regulations, we identified an area which the EPA has apparently overlooked in the proposed regulations. This area is inaccessible valves. These fall into two general categories, valves inaccessible for safety reasons and valves inaccessible because of elevation and/or configuration. Cartain chemical processes ere carried out at such extreme conditions of temperature or pressure, or the chemicals themselves are so unstable or hazardous that the operation is done behind barricades end the like, and, for safety reasons, personnel ere not allowed in theta areas while the unit is in operation. DO 067913 CONFTDFNTTAl ! YZ0028481 -17emissi ns. If proparly implemented w ballava this concapt will provida a * nr a the nacaaaary flaxibility to ad pt a control program * ---- - .thet^is the moat eqtt-effactive for a specific alta. In many instancea a company will now ba able to either implement the valve standards contained in {60.482(f) or adopt a alternative percentage valve approach that more appropriately ran be implemented at a site. We recommend that the Agency retain this concept and needed flexibility in the final regulations. Although are wholeheartedly support this concept# we have a few comments and questions# that need clarification by EPA, in order to improve upon the proposed alternative standard. One matter we believe needs clarification is the criteria the Administrator will use in either approving or disapproving the re quest for an alternative standard as set forth in {60.483(a)(5). We are unclear if the criteria are set forth in only {{60.463(a) (1) and (2)# or in {{60.483 (a) (1-(4). Or in the alternative, are there other conditions and criteria not set forth in the proposal that the Administrator might consider/use in approving or disapproving th use of the alternative standard, we believe the Agency has a duty to clearly set out all the criteria it proposes to consider# the basis for each criteria# and limit approval/disapproval activitl s to this list of criteria. i In our discussion above concerning accessibility of valves# w ftSU'Affffi indicated that for certain^modified facilities subject to these requirements# it was infeasible for safety reasons to subject all the valves to the provisions of {60.482 Cf). Should a facility s k an alternative standard pursuant to {60.483Cal, the accessibility f certain valves would create a problem in calculatin a meaningful allowable p rcentag f leaking valves. W recommend that thes 1 valv s n t be included as part f the alternativ program and be DO 067914 CONFIDENT IAI YZ0028482 !L b ''"'TSHil -AEudwneT-t>r"operator of a modified source subject to tha requirements of 60.462 (f) (!)-() may for valves that ara routinely inaccaaaibla bacauaa of alavation or configuration monitor each inaccaaaibla valve annually using teat methods pursuant to 60.485 or a soap solution for bubbles." "(ii) Whan a leak is detected, it shall be repaired as soon as practicable, but no later than the next scheduled shutdown, or consistent with 60.482(h)." " (iii) For purposes of 483 or 484, inaccessible valves shall not L be included." $60.482 (?) (2) - delayed compliance. Our substantive comments on this section and its interrela tionship with $60,482 Ch) are reflected in our comments on $60,432 (a)(6) above. 560.482(h) - delay of repair Our substantive coscnents or. this section are set forth in de tail in our comments on $60.482 (a)(6) above. $60.483 - alternative standards - percentage of valves leaking The proposed alternative standard for valves in gas/vapor and valves in light liquid service establishes ar. allowable percentage of valves leaking approach for ascertaining compliance. As we have recommended in earlier submissions to the Agency, the chemical industry wholeheartedly supports the concept of using allowable per centages of valves leaking as a vehicle fsr regulating fugitive DO 067915 CONFTOFNTTAl YZ0028483 -19New {{60.483(a)(7) and (b)(5) should ba addad, as followsi "An owner r operat r may terminate complying with an altarnata standard, by writing the Administrator informing of this decision and immediately complying with the requirements of {60.482(f)." dtp. <82 (b)i-tf' Alternate-Morb-Praetiaae. wi ei hi wc ii li ba x is la b pi XM 1- ix IM px c p* Ufl is an In un DO 0&791& CONFTOFNTTAl YZ0028484 -18regulat d pursuant t our proposed 860.482(f)(7). This solutl n would require a modified source applying for an alternative standard to cleaKLy~i3e'ntify in the 860.483(a) (2) (ill) data those valves that will remain subject to 880.482(f)(7). In determining compliance with the proposed 860.482 requirements. EPA clearly sets out a 860.482(1) the standard to be used in deter mining compliance. No similar provision exists for either SS60.4B3 (a) or (b). We are uncertain what, if anything, triggers a vi lation of the Clean Air Act. Or does the Agency mean, if you fail the test set forth in 860.483(a)(4), the provisions of proposed 860.4B2 are reinstituted? In order to make 860.483 enforceable, we recommend that a provision similar to 860.482(1) be added that sets forth the vehicle for the regulatory agencies measuring compliance with 860.483,as followst "(c) Compliance with 860.483(a) in this sub part shall be determined by the performance test set forth in 860.483(a)(4). Compliance with 860.483(b) in this -subpart shall be determined by review of records and in spection ." Another area of uncertainty concerns a sources ability to formally switch from an approved alternative standard back to the requirements set forth in 860.482(f). Tor a variety of reasons, at a point in time it may no longer be cost-effective for a source to comply with a 860.483 alternative standard. We recommend that EPA accord these sources the flexibility and ability to switch back to the 860.482(f) valve standards, after notifying the Administrator in writing that they no longer wish to be subject to an approv d alternative standard, and will comply with the 860.482(f) standards. DO 067917 CONFIDENT TAt YZ0028485 -21percentabe^of valve* leaking under fSQ.483 (*} C33 The advan^bgMof the quality control approach. adxo<ed here is that; (1) grlfKttrniOTiaVi^reductiona'wlllJ^^e^ied industry-wide because there is an incentive'^c^cf''*o, C21 the monitoring burden will be lessened on^pw-'leak plantx&nd^inereased on high leak ones, and (3) w^lA-Tlefined ruler on what can and cannot be done will be table to the owner at the deeign stage. 60.483(c) - Good Performance Incentive Although we believe 60.483(b) is intended to provide industry with the flexibility they need to carry out this program most efficiently, the present wording of some provisions will greatly inhibit its use. In 80.483(b)(3) optional work practice programs muse show a percentage of valves leaking that is egual to or less than that under the 60.482(f) program. Taken literally this would rule out any statistical or probability based inspection system in new plants if they provide the best leak prevention options in their original design. The time to assure a low-leakage plant is when it is being designed and built. Quality control experience shows that quality must be designed into a product; it cannot be inspected in. But the owner needs some incentive to put in more expensive high performance equipment. In establishing a fixed-period, 1001 monitoring program the EPA has provided no incentive to reduce emissions by quipment design since the better a plant is controlled and engineered initially, the less chance there is to reduce monitoring through an alternate work practice. In fact, the required monitoring program does not directly address the real problem of preventing leakage which can be drastically affected by valve and packing selection. This is unfortunate. The regulation should encourage the owner to put in the best leak prevention options available. ! YZ0028486 -20lality c ntrol experi nee shows that quality must ba designed into aVroduct; it cannot ba inspected in. Thus tha tima to assure a -. low leakage planH^J.s^wbaR'it is being designed .and built. Buj: the ownar naada\some incantiva to put in mora expensive high performance aquipmant. X\ establishing a fixed-period, 100 percent jrionitorlng program, tha EPAyhas provided no incantiva to reduce qifcissions by equipment design s^nce tha batter a plant is controlled and angin ar d initially, tha lass balance there is to reduce monitoring through an alternate work pTaeticdw In fact, the required'monitoring program do s not directly address the \eal problem of preventing leakage which can be drastically affected by t^lve and packing selection. What is ne dad is soma "good performance levd^" which, ift designed to and met, would result in reduced monitoring retirements. Snee and xittleman of E. I. d\ $ont da Nemours t Company pr a nted a paper describing statistical inso&hion plans for monitoring fugitive missions from leaking valves on>April\6-17, 1980, to the National Air Pollution Control Technique^ Adviaori\Committee and then followed this up with a second paper (fetter from T.\A. Xittleman (Du Pont) to Glynda E. Willins (Radian Corporation), November 13, 1980) on choosing a good performance level. / These papers provide^ sound technical base f r both statistical inspection plans and performance levels. They show that the required^ inspection program results idv essentially a two percent of valves le/king based on the technical support document model plant examples, xt seems reasonable then to allowvoperators to ad pt inspection/plans that will assure a two percent leakage rate within a plus/or minus ten percent variation. We recommend that 960.483(b)(3) have added to it a secondN paragraphstating - "(ii) Owners or operators may commit to an An- 3^ spection pr gram that will' assure a two percent of valves 1 eking within a ten percent plus r minus variation without determining theV YZ0028487 273 We recommend that th EPA include a third alternative as follows: "60.483 (ey-Varlvef'in'*gaa7vapor and valves in light liquid service good performance incentive. (1) Owners or operators nay commit to an insepetion plan which allows annual inspection after not more than 2% leaks are detected in fiv successive quarters. (2) Inpsection requirements under 60.482(f)(1) and (3) are reinstated whenever the 2t good performance level is exceeded. (3) All leaks found will be repaired and inspected monthly until repair effectiveness is demonstrated in two successive months. (4) Any other inspection plan will be allowed by the Administrator if it can be shown to be equivalent to 60.483 (c)(1).(2), and (3)." The advantages of the quality control approach advocated here is that: (1) greater emission reductions will be realized industry-wide t cause there is an incentive to do so. (2) the monitoring burden will be lessened on low-leak plants and increased on high-leak ones, and (3) well defined rules on what can and cannot be done will be available t the owner at the design stage. DO 067920 CONFIDENTIAL YZ0028488 S.I a. A major incentive would be less inspection for low-leak plants. This makes sen*#;'lov-leak plants should require less inspection, highleak plants more. Quality control inspection plans provide this OFti r. while at the same time including a check for deterioration in performance which, when detected, results in the requirement to return to mor frequent inspection. But before these plans can be used some means f rewarding, rather then penalizing, those who build low-leak plants must be provided, what is needed is some "good performance level" which, if designed to and>met, would result in reduced monitoring requirements. Snee and Kittleman of Du Pont presented a paper describing statistical inspection plans for monitoring fugitive emissions from leaking valves on April 16-17, 1980 to the National Air Pollution Control Technique Advisory Committee and then followed this, up with a second paper (Letter from T. A. Kittleman, Du Pont, to Glynda E. willins. Radian Corporation, November 13, 1980) on choosing a good performance level. These papers provide a sound technical base for both statictical inspection plans and performance levels. They show that a good performance level of 21 leaks is equivalent to EPA's BID basis used to estimate the leak reduction effectiveness of EPA's proposed regulation. It seems reasonable then to allow operators to adopt inspection plans that will assure a 26 leakage rate will not be exceeded. In their papers Snee and Kittleman illustrated the use of a skip-period monitoring concept with a plan which would be widely used for monitoring fugitive emissions. Skip-period inspection plans have been used to inspect the quality of manufactured products for more than 25 years. These plans are widely used throughout industry and have a solid mathematical and statistical basis. Their proposed plan calls for five successive quarters of good performance to be followed by yearly inspection as long as good performance is continued to be demonstrated. If the specified level of good performance is exceeded, then the plant must return to quarterly inspection. Any leaks found must be repaired and monitored until the repair effectiveness has been demonstrated for two consecutive months. The proposed regulation should be amended to provide for the us of this, or any equivalent, alternativ . DO 0679?^ CONFtOENTlAl- YZ0028489 -22a naans of obtaining an quivalency determination of alternative test methods and proc dur s. We recommend that a new $60.485(e) be added 4 . that authorises seeking equivalency determinations of test methods and '^procedures^5h4_ efts forth-the criteria the Agency will use in evaluating an equivalency application. (The procedure would mirror that set f rth in $60,484 for equivalence of alternative means of emission limitation. 860.486(c? - Recordkeeping Requirements This subsection requires that various technical data dealing with detailed schematics, structural designs/ and design specificati ns shall be kept in'a log, that is r-adily accessible, ostensibly et the site. We have no reservations about making this data/informati n available upon a reasonable request of ERA. We do, however, have reservations about being required to collect all this data and house it in one location. As a matter of corporate operations much of this information/data are not always kept together, nor are they needed to be kept together for purposes of assuring and/or demonstrating complianc with the fugitive emission standards. . As the Agency is well aware, the Agency under Section 114 has the authority to require a source to "establish and maintain such re cords" in order to determine whether a person is complying with any standard under Section 111, or carrying out any provision of the Act. The Agency has not demonstrated how the required reports are necessary to ascertain and/or carry out Section 111 of the Clean Air Act. Further, th Agency has not demonstrated why all the proposed information must be kept in a readily accessible location when industry Indicates it will make such data available upon request by EPA. We believe the pro visions in $60.486Cc) as proposed exceed the authority vested under Section 114 to the Administrator, and imposes an arbitrary capricious requirement unlesr modify to reflect industry's willingness DO 067-922 CONFTDFNTTAl YZ0028490 560.484(b)(1) - Equivalence Determination As proposed 560.484 (b) Cl), Units applying for an equivalence determination for an alternativa naans of smlaslon limitation* to tha owner or operator of a facility. We are concerned that this artifical limitation may limit the incentive for or ability to use innovative technology. We believe that the manufacturers and/or vendors of new and/ r innovative technology should also be authorised to apply for an equivalence determination. In a real world context few companies are going to purchase such a system unless the manufacturer and/or vendor will state that EPA has essentially approved the system. Accordingly, if EPA truly desires to encourage the use of innovativ technology, it should authorise the manufacturers and/or vendors to also request equivalency determinations, we recommend that the first line of $60.484Cb)Cl) be modified, as follows: "Cl) Each facility owner or operator, a manufacturer, or a vendor applying ..." 560.485 - Test Methods and Procedures The test methods and procedures set forth in the proposed regu lations are essentially based on the state of technology as of this date. We are concerned that the regulations do not 'rovide the necessary flexibility to approve in the future the use of new instru. menus that may use different calibration systems which provide equiva lent or more accurate results. We believe the regulations must provide DO 067923 CONFIDENT TA1. YZ0028491 -24- data for CPA should CPA want this data, thay can aithar raquaat it in writing diractly from tha a urea r raviaw it at tha facility. Aa 4 the Agancy ia wall aware, aaaa of enforcement ia not a lagitimata gr undo for'requesting tha raporting of data/information unless it ia t also necessary for purposes of determining compliance. As will be noted below, this data/information also duplicates data/information that must be reported under S60.487(b). Tha duplication of data/information sh uld ba avoided by CPA as much as possible. We recommend that $60.487(a) be deleted. As to tha specific information required under $60.487(b) we have th following comments. As a general point, we are only commenting on the specific information requested on in 160.487(b) since the Ag ncy has indicated that the forms and data requested therein are not requirements of the proposed standards. If, however, the Agency changes its mind on this issue, we reserve our right to subsequently submit comments on the example forms on pages 1158 and 1159. Ihe leakless valve data requested in 160.487(b)(2) is irrelevant for purposes of determining compliance with 560.482(f)(6). It is irrelevant the number of leakless seals that exist at a specific pro- c ss unit. Accordingly, 560.487(b)(2) should be deleted* The data requested in 560.487(b)(4) is irrelevant for purpos s of determining compliance with 560.482(f). Compliance can be deter- min d adequately by evaluating the data submitted as required by 5560.487(B)(3)(5) and (6). Accordingly, 560.487(b)(4) should be deleted. In both 560.487(b)(7) and (8) the Agency has not requested the critical point of whether or not the pump/campressor leak was repaired similar to 5560.487(b)(5) and (6). If the Agency wants truly meaning ful data it should consider adding a new provision that would requir this data. on CONFIDFNTTAl- YZ0028492 -26- (8) Reasons for non-repair of pumps and/or c inpraas rs within 15 days aa r quired in $$60.482(a)(6) and/or (b)(5). (9) Number of pumps, compressors, and/or valvaa not rapairad pursuant to tha daeyed"*eomplianoe tima schedule-of $60.482(h). (10) Statamant signed by tha owner or operator stating whether all provisions of 40 CFR 60 Subpart W had bean fulfilled during the reporting quarter. (b) Tha provisions of $60.8(d) do not apply to affected facilities subject to tha provisions of this subpart. (e) In the first report submitted as required in $$60.487(a), the report shall include a reporting schedule stating tha months that quarterly reports shall bd submitted. Subsequent reports shall be submitted according to that schedule unless a revised schedule has bean submitted in a previous quarterly report. Conclusion Although the Agency has mads substantial progress in addressing tha numerous issues the chemical industry has raised on earlier drafts of the proposed fugitive emissions NSPS, we still have several r servetions with the subject proposal. He still have reservations as to the inflexibility of several of the proposed requirements and it still is procedurally more burdensome than necessary for sourc s to expeditiously and cost-effectively Identify and repair fugitive emissions. Zn this regard, CMA has presented several recoramendati ns in these comments which we believe would further clarify and make more flexible the fugitive emissions MBPS program. He urge EPA to giv serious consideration to the CMA proposals and modify the proposed regulations to reflect the concerns expressed herein. DO 067926 CONFIDENTIAL YZ0028494 -25A> we discussed earlier, delayed compliant. nay in some instan es occur after the fifteen day period after leak detection (i.e., next scheduleT'shutdown) or in a few limited instances by necessity after the next scheduled shutdown (i.e,, CMA reooimnended regulatory language for discretionary extensions after the next scheduled shutdown). Zn order for EPA to have meaningful data to accurately appraise a sources compliance status new provisions should be added to ascertain the number of pumps, compressors, and valves not repaired by the next scheduled shutdown, and the number of valves, pumps, and compressors not repaired consistent with a time schedule approved by the Regional Administrator after the next scheduled shutdown.* We recommend that $60,487 (a) be revised, as follows; $60,487 Reporting requirements. Each Owner or operator subject to the provisions of this subpart shall comply with the following reporting requirements. (a) Quarterly reports shall include the following information} (1) Process unit identification. (2) Number of valves for which leaks were detected by the monitoring method specified in $60.485(a) during each month of the reporting quarter. (3) Number of valves not repaired within 15 days as required in $60.482(f) (4). (4) Reasons for non-repair of valves within 15 days as required in $60.482(f) (4). (5) Number of pumps for which leaks were detected during the reporting quarters as specified in $$60.4B2(a) (4) and (a) (5). (6) Number of compressors for which leaks were detected during the reporting quarter as specified in $60.482(b)C4>. (7) Number of pumps and/or compressors not repaired within 15 days as required in $560.482(a)(6) and/or (b}<5). DO 067927 CONFIDENTIAL YZ0028495 ' April 6, 1981 OCi [TO BE ADDED LATER] Respectfully submitted, Edmund B. Frost General Counsel and Vice President Geraldine V. Cox, Ph. D. David W. Carroll, Esquire Janet 8. Matey Chemical Manufacturers Association 2501 M Street, N.W. Washington, D.C. 20037 (202) 887-1100 00 0679pft Confidenttal VZ0028496 A fafMj V<4, 3)7 No. 16 CORRESPONDENCE 1097 fong-tena survival among patients with Slap II! disease i I) per cent (two of eight). Among pauaqjgjwitluSiagt IV disease, 6 of 34 (IB poeetit) hit* survived overall; of the 23 patients with banc metastasb and hone marrow involvement at diagnoaia -- a group generally coniidered to have a particularly poor pragnoaii, S (22 percent) have survived The survival of these five patients indicates that marrow `purging* may not always be needed. There has been a price far survival -- considerable treatmentrelated chronic toxicity. Six of the eight children have auditory injury aiTecting their bearing range* and wear hearing aids. Five patients have reduced glomerular filtration rates/ two of whom have chronic ratal failure; one of them requires antihypertenrive therapy. Apart from ibeae handicaps, the tight children (now 6.3 to 12.4 years old; median, B.2) are leading full and active lives, includ ing normal school attendance. This series is relatively small, but a comparable rate (71 pereens) of response to this chemotherapeutic regimen plus surgery has been observed in a larger study by the European Neuroblastoma Study Croup.* Previous reports state or imply that ao program has been made over the past.10 yean in treating advanced neuroblastoma and that the number of survivors who are more than one year old at diagnosis is negligible.*'' We challenge them assertions. Our experi ence suggests that the median survival of paticnu in Stage III and IV has been extended. High-doec meiphalao is probably ao impor tant component of this improved prognosis*; therefore, the long term remits at tenters using more intensive "consolidation" regi mens*'11' will be awaited with great interest. Rather than adopt a nqpitive attitude, those treating children with neuroblastoma should energetically search far better ieduction and consolidation regimens so that response rates can be improved. London, WC IN 3JH, United Kingdom J. PaiTOMAao, E. Kiuv, D.W. Rooxaa, L Serrr, E.A. Snarroao, R. Buxtron, C. Muulul, arm V.M. Warnin' Hospital far Sick Children 1. BvsmAE. D'AagtoaJ, kiadofchj. A propose* enginf for cNMawMi ssursMssum. Omesr 1*71; 77J74-I. 2. ShsflbrS EA. Regut DW.MschBdJ.AdvmrodeauablsMni: Improved release nu adag s awriipeot septet* (OPEC) lacMing scausasW dseiteb sad VM M. J Clis Oacsl I9S4; 3:W. 3. McHissy VA, Thlbadeut O. Hsyss FA. Oisaa AA. Ksariag loss ia ddldm mcrivbg dspUdn rteaeahuspy. i Psdissr 1M3:102J14-7. 4. Wen* RB. Merited J. Bantu TM. Kraal asdriry of cbptoiaiaehllhta. I Mb* IMS; lOfcttMI. 5. PritchardI.OcRDOotl 3. foots D.deKnkrrJ. LoveS. Uhi|h4ow swlptia- m (HDM) of value is teetotal Of advaaoed aearobMom (AN>7 Prt- BadaiH'iasabsof aniuhualmduislbyBwBaropssaWfiaublaitBeMlIudy QNsp (ENSG). nee Am See Ctia Oueoi 1416:5:20S. ahsuact. 6. Otesfsld J. NnmAlassnms, Hiys OM, ad. to: fsdlstric wtpkri cwxdogy. Ortmde. Ba.: Onm A twain. IMb; 4345. 7. VeaafA.d.Kiaharl.Bucpcs JMV. Tumoursofthssympsstoikasrwxu VestoPA. Bsnaa A. BfoaT^^ln^T^N^Ii^NDtjsdt'csaeer la MMne: eUakal atiatgtoto. M Bedia: Spnagw Varlaf. 19B6: 214-31. I. *i-g--*"* ---- w y--. t----------- - (gyp,! anaiAtssm na with aaptrisAsI dwariui^y, sedteita. sad ttlogsasle or niulsgaro MM roeextetioa. i Ota Oncol 1904; 209-14 9. Hsmuao O, Ksllfa C, Bomlooo P, Boyts C. mhimiai B, Lomrio 1. Itaoneat of odvooood mnUauai whh two coeascudvs high dsn rtwuodiarsyy rvfimsM id susotosous hoas ounaw nsftnin*. la: Bvs AB, D'Aaghi OJ, leopcr RC, edi. Advances la asuiohlsssonw NMorch. Now York; Aloa R. Uu. 19*5:545-1. . PhilipT. Blme P. Phillip I, st si. -r------------------ T----------- far vary hod rim urotilwumt. lo; Evsas AE. D'Aaaio Cl. Sropr RC. ods. Advoaeu hi mudiluioei issooreh. New York: Alan R. list, 1903X0-14. AIDS AND RENAL FAILURE n its Msr.- Roo et al. observed accelerated wasting and early death in paticnu with the acquired immunodeficiency syndrome (AIDS) who required maintenance hemodialysis far therapy of endstage renal disease (April 23 issue).' The course appears to be mere rapid than has been observed in paticnu with AIDS who do not have renal failure. This observation may indicaw that patterns with renal involvement have more extensive human immunodeficiency virus-related disease and therefore die sooner. However, it is also possible that hemodialysis accelerates the progression of AJDfi. Normal Immune stimulation of T helper cells may trigger replicalion of the AIDS virtu.* Furthermore, patienu receiving mainte nance hemodialysis have an inertssed proportion of activated T crib in peripheral blood, as defined fay expression of interleu kin-! receptors.* Whether such activation of T cells rrilecu long term exposure to blood irenstisioni. infectious agents, or dialysis nwmbranes or tubing, or is a manifcatatiofl of the uremic sute itself, it unknown. Intravenous drag use. present in a high proportion of the patienu studied by Rao at al., would also be associated wkh chronic immune stimulation. It might bo interesting to see whether patienu on long-term ambulatory peritoneal dialysis have increases in immune activation of T lymphocytes comparable to the inaaaoai observed in patients on maintenance hemodialysis. If iucseaoad Tcrii activation b more marked in maintenance hcmodialyab than in other farms of therapy of end-ttage renal disease, survival of pa- tieau with thb disorder and AIDS oould be enhanced by an alterna tive therapy (such a* long-term ambulatory dialysis. If feasible). Philadelphia, FA 11M Atax Wamunsm, UD. Casolyn Kiuy, M.D. University of PenneyIvaaia School of Medicine 1. Rao IKS, Rfadaun EA. Nlcerori AD. The types of weal disease b fee eqM teomaedterirocy sy4rwnr. N Engl J Mad 19*7t 31410424. 2. Nabd 0. BtUaon D. Aa mdacfolc esascrgitioo factor scdviaa sip--lin of beam iummodeficbacy vhus b T eelh. Nttaae 1917; 3247114. 3. ChuseoudL,Duauk.BesurebA,eiel. pMsamsaf pteeedveasdTeeMib temedlslymil ynsatt; 4rir postibfc rotr ia sBsred lammasy. Pssc Ned Acad Sri USA 1914 63:74*741. '' BENZENE AND LEUKEMIA , 7k Mr Erifer; In the study on faenxene and leukemia by Rinifcy et al. (April 23 issue),* there were but nine casco of leukemia and four cases of myeloma. These etc very small numbers on which to base conclusions, especially when the overall mortality bee been is expected and the mortality due u malignant neoplasms has also been ee expected.. Of special interest it the authors' Table 4, which Hsu the cases. Some had minuscule exposure, and one wonders what other malig nant dbease-cauau^ agenu tbry may have been exposed to during their fives. Of apodal interest b the fact that no employee first exposed after 19S4 bed leukemia or myeloma, even though hiring continued far II yean and even though 7 of the IS cues had the cruet of disease within 20 yean of first exposure. (Caem were fal lowed through 1961, so there should have been some cues.) la the study, two subjects died within 3A years of exposure. Looking st the ytxr of Initial exposure of the 13 cases, one can see let t had first expuutcs before the end of World War II. One wooden about the owasaring mairumeau in that situation. Having ipeai tome time studying childhood malignant dbcaac mote than 23 years ago, I am very sensitive to the tendency to observe dusters of cases sometimes firing within short distances of cadi other. Sutisuciana have generally attributed these to chance, and there b no reason why that may not he true in the cases in thb Mndy. Seattle, WA 961 IS Max Baocx. M.D., M.FJi 4336 29th Ave. NE Rimky RA. BaiMi AB, Hemeag R. et si. Bsaasat md briteada: an spMsmlobglc risk sssssftwrst, N Esgl I Msd 1917:1I4KM4-50. n Mr E&Ur: The paper by Riasky rt al, an workers in robber hydrochloride plants rxposed to benseisc reports a cohort ttudy, a case control study, and a risk aetesemeut far leukemia in friadan to benzene. Table 1, which use* data feam that paper, indicates a discrepancy between the cohort and case-control studies. Tbecaso- 0 y00 (-) y ^ CONF J0NTIAi YZ0027906 1036 THE NEW ENGLAND JOURNAL OF MEDICINE Oct. 16, 1967 ToMt 1. Mate from Laukamia, Iht Standardizod Mortality Ratio - (SMRhand te Prodictod-Odds HaUa^ Acootdlno to CumylMhro fetpaautfTo Banzana. dwtOnulM buHI Own tuners* 'MO OontUno* (MO 40-100 100-400 >400 2 l.l 1.3 3 12 4.3 3 11.** 43.1 J 46 423 "ft--Huibbsreiresniarelat X14sb> nsl . nwriunmciintsstb (440 rpreyssts In Helen ssuasiy). study." Since substantial number* of health worker* are exposed lo formaldehyde. it would be of considerable interest if Dr. AtkM could provide the evidence (hat indicate! "a clear risk of cancer to human*." St.John's, NF AIB SV6, Canada M. Hntav Gault, M.D. Memorial University of Newfoundland I. AddMNA. New KhaiUe evidence andpiMc health bapctiti*.Nni0J Mad 1967; 316:1064-3. 1. Blah A. Bwwwt P. O'Betf M. at at. Mortality sac* Musaial western eifoead to Icmuldrhydt. INC! 1966; 7*107144. control risk asaeaatnent predicts, in the higher-exposure categoric*, odd* ratio* much larger than the standaidiied mortality ratio* ob served ip the Cohort. A possible explanation for the discrepancy i* that the expoeure of the controls was much lower than that of all cohort members without disease. In support of (Ms, it out be In terred from the paper that the mean cumulative levels'of boatat exposure of the 1136 subjects without disease and the 90 controls were about 67 and SO parts per million (ppm)-ycan, respectively. It Is reasonable to ask why the case-control study was done. A caic-anul study within a cohort is usually done to reduce the cost of determining the exposure of all cohort memben without disease. However, this reason is not applicable here, since the exposure to bensene of ad cohort members wa* known. Rinsky ct at. offer sever al reasons for doing the case-control study, but all the objectives could have been met effectively by a cohort analysis of all the data. The disparity between the mean expoeure level of all cohort members without disease (67 ppm-ycan) and that of the 90 control* (60 ppm-ycars) requires explanation. It is probably not the result of election due u matching, since this should have rawed the level is the comparison series. The investigators may have reviewed the information on the bensene exposures of cases and controls, with the result that the avenge level of the controls, but not that of the cases, was lowered. If such a review explains why the Control expo* sure levels were lowered by 36 percent, then the validity of the cohort study is questionable. Finally, if chance explains the differ ence between the cohort data and the case-control risk assessment, a risk assessment based on the entire cohort would be superior. Irrespective of the cepUnxtion, it would be appropriate so evaluate the data further. Although this might Involve reevaluation of the benxene exposures of all cohort members, the result* should clarify the relation between benxene and leukemia. The Occupational Safety and Health Administration (OSHA) proposes so reduce the benacnc standard of a 10 ppm time-weighted average to I ppm. A principal basis for this is the results of the rubber hydrochloride study. However, the magnitude af the doacresponie relation in this cohort is uncertain. We, fat a review supported In part by Texaco, Inc., and other* have done risk suotmenta based on this study and estimate that exposure to 300 ppsnyean of benxene would cause SO to B0 excess leukemia deaths per 1000 workers so exposed.* The risk assessment of Rinsky ct #1predicts 230, Birmingham, AL 33394 Hablaud Austin, D.Sc. EutABira Otuiu, DJo. Flour Cols, M.D., Da.P.H. University of Alabama at Birmingham School of Public Health *AvsUa H. Dctssl E. Cote P. Beaasae Ml levkamls: a mww of Six Mirrwwt m4 risk assured Amlfipldrerfnl (la press). 7* lit Alar. In his editorial on new scientific evidence and public health imperatives (April 33 issue),1 Dr. Ashford stated that "anaeher example b the reanalyri* of the National Cancer Institute data on human exposure in formaldehyde,' which now indicate* a dear risk of cancer to humane." The author* of the study of homsAi exposed so formaldehyde* concluded that "these deta pro vide Stile evidence that mortality bom cancer is associated with formaldehyde exposure at the levels experienced by workers in this r* lit EJUm: The editorial by Ashford sounds a false alarm about the slate ofpublic health regulation today. Far from "waiting for the bodice to feR," federal agencies long ago adopted the "preventive public health policies" that Professor Ashford now pleads for. The Supreme Court's decision in die bcnicne case accepts this approach by authorising OSHA so "risk error on the side of ovupreetevion rather than updcrpratection."1 The essence of the court's ruing is that this principle must be applied within realistic limits, so that instead of seeking "to eliminate completely end with abso lute certainty any risk of serious harm," regtdatorx must biriy evaluate iN the available scientific data and "make a rational judgment about the relative significance of the risks" involved.1 Federal agencies have recognised that prudence, rather than anittconccived rush tojudgment. Is crucial to sound public health regu lation and have had no difficulty implementing the vital risk sisetsreent and policy-making disciplines contemplated jn the ben* tene dcdsion.3-4 In feet, OSHA ha* already regulated asbeesae* and ethylene oxide* as carcinogens and will shortly prescribe stricter limits for formaldehyde.' The report by Rinsky et al. on a much-studied cohort of benzene workers, which Professor Ashford cites as "better science' requiring an Immediate "governmental response," actually illustrate* the pitfells of reacting uncritically to a single publication. Indeed, HfeQslo meet the standard of scientific excellence to which he subacrihea. During OSHA'* public hearings on bentene last summer,1 mqjor shorteoaMng* in the paper by Rinsky et al. were uncovered, includ ing selective use of the available data on industrial hygiene; sub stantial underestimation of exposures, particularly during the 1940a, at the work stations where the excess cues of leukemia oc curred and where workers were known to have died from the acute blood-poisoning effect* of benacnc*; and failure to account foe the prolonged, heavy exposures to bensene that many of the work ers in this cohort experienced at work stations excluded from the analysis.*-1 There is nothing to be gained and much to be loet by fomenting a crisis atmosphere based on a Sawed analytic that greatly exagger ates the level of risk, especially since average benaene expeauwa in the petroleum industry and elaewhere have for tome time been re duced to level* comfortably below the 1-ppm Hralt OSHA ha* pro posed." Instead, Protestor Ashford should recognise, at the Ameri can Petroleum Institute doe*, that the ben way to improve health protection against the hazards we fees today -- occupational and otherwise -- it to insist on a thorough scientific review of ail the available data, focusing on the question of what exposure* pore significant risk*. Washington, DC 30006 WtuiAJU F. O'Kaivx American Petroleum laadtdte I. AfL-CIO v. Ainks* ftnektre lastiww hriasnW Ualoo DspamuM. 441 U.I., 1460*07,636 1. Raaasi M. Orvtxr 14. Bin........ .. in rerisrere^l polity tnkla*. 3cfe*e* 1467; U63I6-90. 1. Lam LB. Haaldi aad witty rbfc analytet: fefonmdo* for bemrdadsloee. Idaret 1967; 236391-3. 4. Oksaut D. Tha safety soak af 6w U.l. Nadaar Repstaary Coaahds*. drees 1917; 23*296400. 3. Kqawn af Labor- nrrMpartnad aapoarea * aabtrew. anaiBa. aodteyhllliaj. aad actlreln*. Pad Baglai. Jaw 30, 1916; 31:2361290. 6. Qtpirtwaatof Labor. Oncapdlcsaleapaareswadijlrei add*. ftdfoght Ivw 32, ||4; 4936134^" DO 067930 CONFIDFNTTAl YZ0027907 1030 THE NEW ENGLAND JOURNAL OF MEDICINE Oct. 15, |BB7 iceberg (tvnli -{vc Alf far mm iti-onncoved ruahc* to judgment. On the contrary, the regulatory agencies have sometimes been dragged kicking and screaming into action neces sary for fulfilling their itatutory mandates. In the meanwhile, work* era and citireru ary harmed. An example it the evolution of ecienoe regarding the carcinoge nicity of formaldehyde. The National Cancer Inttitute (NCI) itudy in 1986 aMerted that there wat "little evidence that mortality from cancer it auociated with formaldehyde exposure at level* experi enced by worker* in thit aludy." In a later publication1 the tame author* concluded that Detpiie (null number*, the date-dependent ettodatiou 11 naso pharyngeal cancer with expoture to formaldehyde and particu late* deterve* further invetligation through cate-control atudiet, where the influence of formaldehyde end pirtieulatc* may he evaluated with more tiatitpcal power thtn by itandard cohort ttudie*. Further anafytit of the NCI data by Sterling and Weinltam* reveal* a clearly increa*ed risk of lung cancer. At congreeilonal hearing* in 1988, the Director of the NCI, In commenting on the earlier work, tettified that "in ataociatien with particulate*, there it an aitodadon between formaldehyde and naiopharyngeal cancer, which clearly ha* to be followed up."1 3 The irony concerning the critidtmf of the adequacy of the toenoe it that the tcxntific evidence it ettentially there. OSHA hat jutt decided to reduce die permittibie expoture level for benxene io I ppm. It waited for loo long. Let there be a better governmental response to the new realitie*. Nmhola* A. Atnroan Cambridge, MA 03139 Massachusetts Inttitutt of Technology 1. W*ir A. foewan PA. Hoover RN. Fmuneal JF Ir. cl al. Oma of At aawphtrytut tad orayturyu tad WnutdcOyOr mmui. JNCI1MT; 31: I9I-I. 2. IWlag7D,Wtiak*aiJI.>riN*iusdfardxiBcaMMV*OSHAHca*b|tM Famulikhydr. Itihntbtio* IU>. Novcabtt IM6. 3. Fmmlddtydt Itudy- Hmibg beta* the Ithetwtot *n Ovattlgki tad fovetrifttitra of the Comuiuec oe Eacr|y aod Comasrei. Houtt W RoptuitatttivM. My It, 1916:106. THE EC-IC BYPASS STUDY T* tit fokm Hie recent discussion (March 36 issue)1"4 of the exiracranial-lntrxcnnial (EC-IC) arterial hypa** ttudy b very timely. 1 would like to tpeak to one ataiemem in the editorial: "The conchaaiona of the EC-IC trial are valid ibr the population of patienU studied"1 The population that underwent turgtry included patient* who had only one epbodc of the tramient itrhcmk attack. Mott neuroturgtont who are experienced with the bypatt procedure wouU wx accept fix turgical contideration any patient with a tingle trantipnt bchemic attack. There i* no dbcuuhm in the original report of the randomired ttudy* about bow many of the patient* who underwent turgtry were in thb ordinarily nonoperative group. SobaequcM re port* by the author* of the randomised ttudy have never clarified thit Itme. Rcgardlm* of whether the raodoraiiation of the patient* wat proper or not, the mere foet that patient* with one tramient bche mic attack were included in the ttudy negatrx the concept that the conclusion* of the EC-IC trial are valid fix the population of the patient* atudied. Un Angelct, CA 90048 Milton D. Heirxrt, M.D. Ccdara-Shtai Medical Center I. ttlnai AS. The nttriaalil laatri--itl *ntdtl kypatt wady: What hate u* lasnait N Bagl 3 Mad 1967; 3IU09-M. I. Saadi TM Ir. Wat the lainaninail nadembad VM of ttirarimM lane- maid trend bypatt ngntittathe of Am pnpiilnlta *e ritltT W Eagl i Med I9t7; 316*144. 3. Otldring f. Zcrvtt N. Laagta T. TW -mrmitil Inaimritl Bypre datdy. a upon af be iniaimiwi ipfilttnaydit AattrlttaAtatcIttbaef Ntwotoglcal (Mgtem rtandw Me nudy. N Eagl 1 Med I9t7; 316:117- 4. Btiuta WM. treks* D.TryVe PW. tl *1 Art Mt rreutu of *u * tiii-bemaitl bypre* uul prentiut4*7 N Eagl 1 Mtd 1MT: 316 139-4. 5. The BOlCiypau Study Omup-Fafflm of txncaaaiaHamcraalal mnM bypatt xi nduct the rtafc of hdxade mtike: Ntah* of ad liinimnliiml itndeedmd eiil. N Eagl 1 Mtd IMS: 313:1191-100. T* Ai EAun The Special Reporu in the^uaaf of March 36 on the validity of the international randomised trial of extracraniaiiotracranial arterial bypatt, lint publiihed in the ./rental in 1883,* induce tome thoughu about the findings. Specifically, the implica tion of the finding* for a better under*tending of the pathogenob of ischemic itroke i* of interest. The result* arc folly contbtent with the hypotheeb that iechentie strokea are largely emhdic in origin. The relations among traiuiest ischemic attack*, completed ttraltes, and etheroaclerotic plaque* cf the internal carotid artery were well retablbhed before the Mudy wat done. Emholi from ulcerated plaque* or oedutive ktion* of die internal Carotid artery or middle cerebral artery would presumably lodge In a brain vend ditul to the anattomotis, who** only dfoct could then be to improve marginal or collateral circulation lo the periphery of the territory where the inform occurred. I* it too limpllitk to attutne that in the care of the carotid kaioat, a natural bypaia already cxiiu -- the drdc of Willi*? One of the postulates of the ttudy wat that lesion* of lhc middle cerebral aruxy would be especially tuksbie for bypatt surgery. In fret, the existence of such lesion* generally Indicates mow revere, widespread atherosclerotic disrate, with the attendant risk ofstroke from embolism originating in the internal carotid artery or aorta er death from coronary heart disease. Montreal, PQ H3A 2B4, Canada Stax Mooax, Mil. MoGHl Univcnity *Tht BC/IC lyptm tody Oreu Fdhai d taUtnuilil kxiarreabl MMhl kypM tetedaw the risk cf IMxadc teokt: waht af -- Itti nnliml imOre bad trial. NBaglJ Mad M*J: 313:1191-100. Tt Ai EAtn: The jkehMl b to be congratulated for hi com plete handling of the controversy surrounding the EC-IC Oper ation.'"* However, we strongly disagree with the conclusion* of both the neurosurgeon*1 and the Editor,1 who seems lo have been impressed by the neurosurgeon*'argument* and to cast a rindew on the proper interpretation of Mich trial*. We agree that gen eralliability b strengthened when most eligible patient* aw ran domised, but we insist that the results should stand unless or until an even hence study repudiate* them. In the meantime, there who insist on using thb now-discredited operation Mould not expect third-party reimbursement until they provide credible (Le., weM-eontroiled experimental) evidence chat contradict* the EC-IC study. The cmlied-for retrospective review of the outcome in the nonrxn- domised patients world be at wurthkxs as airy uncontrolled hittcri cal survey-It would he impossible to ton uul selection foctere from treatment effects. Some patience selected for operation rather than raadorniiauon might do worse than those randomised, beesuse the more threatened patients were treated nxgicaily, and tone might live longer because their good condition made them attractivesurgi cal candidate*. Whichever predominated, the result would be xafct- terprttable, as demonstrated by several published comparisons of survival of randomised and noaraadomiaed patients who aeemed to have the tame pregnoai*.'"* If tuigcona have reservation* about the validity of randomised controlled trials because their patient* were not entered, the problem b easily solved by including nil eligible patieatr in future ttudie* that have the prior approval of thoae surgeons. In our experience, patients readily accept randomisation when their physicians are convinced of its vxitdky. When told af the results of the trial and the lack of any evidence favoring surgery, they would prefer randomisation n an operetta, based on rargicai judgment alone. A* suggested by one of u*,1 the study could be paid fix with the money saved by operating on only half a* many pa tients. In the meantime, there b no accent*bie evident* iktt the - ------ DO 06793? CONFTDFNTTAl. YZ0027909