Document 7REpRMdgnKZwYrjrrpg8919Oo

ST00I2853 r % James W\ Hammond, Sr. IfJO TouHpJuj* Pm.ut Houiion, TVauj 77057 February 16, 1989 Hr. William Baggett P. 0. Box 7820 Lake Charles, LA 70606-7820 RE: HISTORY OF RECOGNITION, EVALUATION AND CONTROL OF HAZARDS OF ASBESTOS DUST IN THE PETROLEUM AND PETROCHEMICAL INDUSTRY FROM 1930 TO 1970 Dear Mr. Baggett: In 1937 Mr. Roy s. Bonsib, Chief Safety Inspector, Medical Department, Standard Oil Company (N.J.) released his bulletin, "Dust Producing Operations in the Production of Petroleum Products and Associated Activities." He subtitled the reportL "A Medico-Safety Survey." Dr. w. J. Denno, M.D., General Medical Director of Standard Oil Company (N.J.) wrote a foreword for Bonsib's bulletin. Because Dr. Denno so clearly and concisely expressed the moral duty of the petroleum industry for its employees, the full foreword is attached. See Item "1. One may know that he expresses his management's policy for the N.J. Company and all of its affiliates. In 1947 Humble Oil and Refining Company's board approved the sharing of industrial health knowledge and medical experiences with the API members and with its customers without reservations. I was employed by Humble in 1947 to supervise industrial hygiene. In 1937 Mr. Bonsib wrote that dust was not only a nuisance but was recognized as dangerous as a cause of occupational diseases. He quoted Professor Philip Drinker, Harvard, "It would be well to realize that men working in dusty trades suffer far more from respiratory troubles of all kinds than do men who work in clean air. The evidence that -excessive dustiness of any kind is harmful is beyond argument." Professor Drinker give examples of hazardous dust by naming asbestos and silica. He read his paper before the annual National Safety Congress, October, 1936. Mr. Bonsib referred to silica and asbestos dust as being highly hazardous when inhaled at work. Mr. Bonsib referred to the broad studies on animals that had been carried on by both the U.S. Bureau of Mines and the U.S. Public Health Service. He referred to publications of these studies by these agencies and the National Safety Counsel. Occupational exposure to asbestos before 1937 was known to have caused loss of lung capacity, and an enlarged heart. DOUI 00974 ST00I2854 These diseases were known by Mr. Bonsib before he began his study of the Oil refineries in 1936 or 1937. The study report listed the many workplaces in the refineries where asbestos is commonly used in large amounts. The attached several sheets are taken directly from the report of his industrial hygiene study made in 1936 and 1937. See Item #2. At the end of Mr. Bonsib's Bulletin one's attention is attracted by the list of authoritative experts who he conferred with. His standard for dust concentration that could be tolerated without high risk was used by government and industry until the 1960's. His method of evaluation was acceptable for a like period where a close estimate was suitable. Mr. Bonsib studied those dusty operations where asbestos was present. In 1937 he described the nature of the work practices, locations, physical methods and average dust concentrations in several refineries. His recommended measures for controlling dust in oil refineries are basic ones for today. He failed to emphasize substitution of non-asbestos insulation and filler materials. However, as shown by the experiences of those employees who worked with asbestos and used his safety measures their exposure was under control. As early as 1942 a national standard for asbestos dust of 5 million particles per cubic foot (MPPCF) was commonly recognized. This Maximum Allowable Concentrations was set by a group of authorities representing a good cross section of governmental, insurance, and industrial representatives. These experts were a committee of the American Standard Association. Dr. James Sterner, (1942), in lectures and in publications in several medical schools, and journals, both safety and industrial hygiene, discussed the MAC values. By 1950 the experts issuing MAC values had united behind the threshold committee of the American Conference of Governmental Industrial Hygienists, (ACGIH). This committee is still active and publishes those TLV's annually. Before a value is changed a national notice of the intended change is circulated for two years. This notice alerts all parties concerned to come forth with unpublished information to guide the TLV committee. Since 1948, the petroleum industrial hygienist and safety inspectors have discussed those proposed changes in API professional committee meetings. Beginning with the asbestos TLV in 1950, the changes by the TLV Committee were none until 1968 when the supreme DO^i 0097 5 ST00I2855 importances of fibers was accepted. The TLV for asbestos of 5 million particles dust per cubic foot (total count) was reduced to 2 MPPCF or 12 fibers per milliliter of air. The fiber was defined as to its ratio between length (more than 5 microns) and its breadth. Item #3 shows how few changes are made for the long list of substances in any year. Also it gives one a clear definition Of TLV's. The next enclosure marked Item #4 is added because of its concise history of occupational diseases from workers1 exposure to asbestos. It was found in ``Documentation of the Threshold Limit Values and Biological Exposure Indices", 5th Ed. 1986. This publication was issued by the ACG1H, Inc. The latest edition may be purchased from Am. Conf. of Govern. Hygienist, Inc., 6500 Glenway Avenue, Building D-7, Cincinnati, Ohio, 45211. Blazer and Cooper in 1968 published results in Am. Ind. Hyg. Assoc. J. of their study of the work environment of insulating workers (v. 29, 1968). Dust surveys were made in small and large industrial plants. Dust concentrations by insulating job classification, based on both million particles per cubic foot and fibers per cc (ml) are given in attached tables. See Item #5. Past concentrations standards for asbestos were based on MPPCF until 1968. In that year the TLV Committee recognized the improvement of the TLV by basing the value on fiber concentration. The concentration values by MPPCF to fibers per cc by a multiple of approximate 6 or divisor of 6 are to convert fibers per cc into MPPCF. The fibers with a length of greater than 5 micros are the ones that are converted in fibers per cc. The Hygiene Guide Series, AIHA, was prepared by professional and certified industrial hygienists. These scientists are from industry, universities, government and research institutes. The Guide for Asbestos was prepared before 1962, and therefore, is a sound standard and state-of-art for the period from 1940 and before/tantil 1960. An article by Harold Scarlett, a known legible reporter, is attached as item #6 for your information and files. It is a good example of how broad the asbestos health hazard is. Yours very truly JAMES W. HAMMOND, SR DOW 000976 ST00I2856 FOREWORD Because it is the duty of industry to protect its employees and because no comprehensive survey of the hazards incident to oc cupational dust problems had yet been made, it was felt that here was an opportunity to render a serivce to the petroleum industry and its employees by making such a survey. It is hoped that the information presented in this bulletin will assist in finding proper answers to some of the'many questions which have recently arisen concerning the health hazards of employ ees whose work involves exposure to dusts of various origin. An atto&pt has been made to consolidate opinions from the most experienced students of occupational-dust problems to show the relative hazards of dusts and the duration of exposure which stay prove harmful to the worker* Furthermore, a study of the prevalence of dust particles oc curring in various operations in the petroleum industry has been made and included in. this report; also a description of the pro tective devices and equipment provided for the protection of the workmen. This report should serve as a guide to operating executives and safety engineers in handling personnel and in providing adequate protection in dusty occupations* It should also resolve many of the fears and questions of industrial workers in these occupations* The study confirms an opinion that dusty occupations, thor oughly understood and intelligently handled should result in no serious disability* General Medical Director Standard Oil Company (B*J.) ITEM # 1 2 DOW 00977 ITEM 2 STOOI 2857 III - INSULATING OPERATIONS Insulation plays an important part in the processing of petroleum products* [The two types of insulating material most frequently used are "Sponge Felt" (asbe.s- \tos with ground soonge to give dead air space and thus increase the effectiveness of the insulation; said a mixture of 85# magnesia and 15# asbestos* Rock wool is used to a considerably lesser degree* In the ordinary ccrimercial form* Rock Wool* as used at our refineries* does not present a dust hazard* It is also used for house insulation* and is available in small nodule form which ean be blown into /place* "85# magnesia" is a mixture of magnesia and granulated asbestos and pressed 'into blocks of various sites and shapes (usually 16" x 18" x l-l/2")* The most dust comes from dismantling old insulation and grinding scrap material for use as a plas ter or "ganister"* The average service of men engaged in insulating operations is about fifteen years* Host of these men have been transferred from the Cannon Labor Department. They work nine out of fourteen eight-hour shifts* in gangs of from two to six men* and are actually exposed to dust for less than sixty per cent* of their working time* Goggles are sometimes provided* and occasionally MSA "Coofo" Respira- /tors, but this equipment is not used as much as it should be* Generally speaking* I about 85# of their work is with sponge felt and 15# with 85# magnesia insulation I At one of the larger southern refineries about 500*000 square fee$ of sponge felt and ^-60,000 square feet of 86# magnesia are handled a year* * A Wh*t Physiological Reactions are Provoked by Insulating Materials? According to Dr. Leroy U. Gardner (Journ* Indust* Hyg* Mar, 1937*Vol* 19, No* 3* P, 121) asbestos dust with its fibrous particles does not seem to be readily handled by the protective mechanism of the lungs* Quoting from his articles "They are not removed to the lymphoid tissue but remain in contact with the delicate walls of the air spaces* They become surrounded by an iron-containing coating that fractures and gives rise to the pecu liar structures laiown as ,asbestosis bodies1* The fibers are irri tating, perhaps because of their form, and they excite a fibrosis which begins about the terminal bronchioles and spreads to form dif fuse patches in the parenchyma. Often the distribution is sub-pleural. In the presence of infection* the reaction to asbestos dust is much more severe than that caused by the dust alone*" There is nothing in the pertinent literature, nor does the Bureau of Mines blow of any evidence* which would demonstrate magnesite (a natural magnesium earbonate) to be harmful* It would fall in the class of "nuisance dusts" such as gypsic* While many of the so-called "nuisance dusts" have never been found to be harmful* it is the opinion of most investigators in the field of industrial hygiene that no work er should be exposed to any dust in a concentration exceeding 75 or 100 millions of particles per cubio foot of air* B - What are the Principal Insulating Operations and Bow Much Dust is Produced During Such Operations? There is, of course, a wide variation in the amount of insu lation work and the amount of dust produced* A few examples* however* will give a good general ideas INSULATING 12" STEAK LINES* 6" x 18" x 1-1/2" blocks of 85# mag nesia are tied on the steam line with 14-gauge galvanised wire and covered with roofing paper to make it waterproof* Often times this work is performed on scaffolds twelve to fifteen feet above the ground, with men lying on their backs under the line part of the tine* DOW 00978 8982 100IS Considerable dust (as high as 18,124,800 particles of less than tea microns per cubic foot) results from tapping the blocks into place* Samples taken during the entire operation had an average concentra tion of 6,881,760 particles per cubic foot* About 90# of these dust particles were slightly angular, crystalline in appearance and above five microns or less in else (as seen under the Konimeter Microscope)] 5# were rounded opaque, ten microns or more in sise] and 5# were opaque scale-like, five microns or more in sise* Samples taken while applying asbestos sponge felt to a 12" steam line had a dust concern-' tration as high as 23,788,800 particles of ten microns or less in sise per cubic foot* The average was 12,574,080 particles per cubic foot* These dust concentrations are considered too high for work ing without adequate protection* INSULATING A 750-POUND CRACKING COIL ACCUMULATOR: 6" x 36" blocks of Johas-Manville "Fire Felt" are first applied and plastered with extra AA Rubberold Asbestos Cement and waterproofed with JohnsManville "lasulkote", The dustiness of handling these materials has been considerably reduced since the manufacturers began shipping the "Fire Felt" in cardboard cartons containing thirteen or twenty blocks, and the plaster in hundred-pound paper bags* Samples taken during this operation had an average dust concentration of 4,502,880 particles, ten ailerons or less in sise per cubic foot* About 75# of these dust partioles were slightly angular in appearance, five ml- * crons or less in site] 10# were scal^likej opaque; and 15# were ' rod-like and fibrous* INSULATING TREATING PLANT ACID SUCTION LINE: Seotions of "Sponge Felt Pipe Cover" are cut to fit pipe lengths with an ordinary carpen ter's hand saw* This operation produces on an average 621,280 par ticles of dust, ten ailerons or less in size, per cublo foot. Under the Konimeter Microsoope all of these particles are slightly angular, crystalline in appearance, and five microns or less in size* The blocks or sections of the pipe cover are held in place by wrapping #16 gauge galvanized wire about each one* INSULATING CRACKING COIL HOT OIL LINES: All hot oil lines at crack ing coils are insulated with 2" asbestos tubing (85# magnesia and 15# asbestos) held in place by fine copper wire* Sections of the tubing are cut to fit particular areas by means of an ordinary carpenter's hand eaw. This produces 7,788,000 particles of dust, ten microns or less In site, per cubic foot* Under, the microsoope, 90# of these dust particles appeared to be rounded crystalline and about three mi crons or less in size* Each section of tubing is pounded into place with the open hand so that it fits snugly against the pipe, and then wired into position* The dust produced from both of these operations averages about 3,379,520 particles per cubic foot* Under the micr^ scope, approximately 80# or 90# of the dust particles appear crystal- line, more or less angular, and five microns or less in size; the re maining 10# or more are rounded in appearance, and over ten microns in size* DISMANTLING OR REMOVING OLD INSULATION: As a general rule, the dismantling or removal of old insulation is & more dusty operation than the application of new insulation. The old insulation is chopped or cut with a hatchet or small hand-axe, and pried loose and pulled off with the hands. This produces dust concentrations as high as 5,890,560 particles, ten microns or less in size, per cubic foot. In 000,79 ST00 I 2859 3 3 dismantling an old cracking coll 4n tar line, the average dust concen 3 tration was 2,322,240 particles per cubic foot* In appearance these particles were clear crystalline, rather rounded, and five microns or J less in size. No fibres were observed in any of the dust samples from dismantling operations* After a few weeks or months serviee, insula l tion on hot lines dries out and appears to disintegrate. This is prob ably due to the fact that such insulation is usually eovered with a l weather-proof material vdiich prevents absorption of moisture from the - air. 3 CRUSHING SCRAP ASBESTOS: Serap asbestos insulation, usually the 3 85# magnesia typo, is crushed in a belt-driven Williams crusher to pass through a screen with one-inch holes or slots, and is then mixed with i new asbestos to make insulating plaster* This operation, which is a very dusty one, is performed by two men, with an average service credit 1 of about twelve years* Goggles and MSA* "Camfo" or Willson Dust Respi rators are worn* Considerable dust is produced in breaking up the i sorap Insulation by hand prior to crushing (10,195,200 partioles, ten microns or less, per eublo foot), and also when feeding the crusher whloh is done by shovelling the broken-up pieces into the hopper and poking them down with a short wooden stiek (14,839,680 partioles per eubio foot)* Dust oounts as high as 27,527,040 partioles per eublo foot were found in samples taken from over the hopper* These dust coneentratlons are dangerously high* About 95# of these partioles are sharply angular, crystalline in appearance and five microns or less in nisei S# are opaque scale-like, six miorons or more in else* Crushing sorap asbestos is not a steady routine operation, the exposure varying from eight hours a month to about twelve hours a week* CRUSHING OLD CORK INSULATION: This operation is performed approxi mately twice a year and takes about twenty or thirty minutes* The in sulation is crushed on a belt-driven Williams crusher, by the same men who crush the serap asbestos* This crushed cork is used for insulating lines in the cold settling plant. The average amount of dust produced is 20,016,178 partioles, ten microns or less in site per cubic foot* About 80# of the partioles are slightly angular, crystalline, in ap pearance, and five microns or less in size; 20# are round, semi-opaque, ten miorons or more. There are also a large number of very small black or dark grey specks. - QUNmrarOPERATION Ifagt.is Cunite amd ?- '"Plaine-is- mtxtuir uf auui uarimatelu-- DOW 00980 ST00I2860 TV. - CRUSHING FIRE BRICK - Fire bricks are crushed in a belt-driven Williams or a Motor-driven Sturtevant Brick Crusher so that 80# will pass through a 3/8" or a 150-mesh screen - much of it is powdered during the crushing* This material is then mixed with fire clay, crushed asbestos and cement to make "Ganister" which is.used in tube sheet linings, packings or as mortar in building fire boxes of furnaces* Samples taken during the crushing of fire brick had dust concentrations as high as 11,554,560 particles ten microns or less in size per cubic foot and a general average of 2,562,960 particles per cubic foot. Crushing new fire briok produces about six times as many dust particles (4,375,733 per cubic foot) as is produced when crushing old. used fire brick (736,320 particles per cubic foot)* Under the konimeter mi croscope about 94# of the dust particles produced by crushing new fire brick appear angular crystalline, one mioron or less in sirej about 5# are opaque over ten mi crons and about 1# are dark opaque, scale-like about five microns in site* The dust particles from crushing old used fire brick are more rounded crystalline in appearance and are about five microns or less in size* An analysis of Alamo Fire-clay Brick, which is commonly used and was the new unused fire brick being crushed at the lme our samples were taken, supplied by the manufacturers (Harbisea-Walker Refractories Company) reports* Silica.................................... Alumina and Titania......... Ferric Oxide......... .. ..................... Magnesia................................ Alkalies............................... per cent, n Tt tt n tt tt tt tt tt Fire brick is crushed by two men assigned from the Labor Department, the aver age service of these.vmen is about 14 years* Two to three tons are crushed per day. The total length of exposure per month depends upon the demand for crushed fire brick and will vary from a general average of fifteen hours per man per month to as much as twelve hours a week. Goggles and M*S.A*Comfo dust respirators are worn* V. - SHAPING FIRE BRICK ON IMERY WHEEL - Fire brick are ground to a specified shape end size on a 2" x 24" Carborundum (Grit 16, Grade 1, Bono 6C) Wheel which re volves 900 RFM, This wheel is almost completely enclosed by a hood which has a 4inch duct to a 24-inch motor-driven fan operating at 1750 RFM., but this exhaust is evidently inadequate as samples taken while rounding off the edges of a fire clay fur nace block had a dust concentration as high as 4,078,080 particles ten microns or less in site per cubic foot of air. The general average was 2,001,658 particles per cubic foot. All of these dust particles were slightly angular and slightly opaque in appearance under the microscope and five microns or less in site. One man wearing goggles and a K.S.A. Comfo respirator, with about 15 years service, spends an average of about two days a month shaping fire brick and blocks on this v&ieel* VI. - DISMANTLING MASONRY - Dismantling Masonry structures such es old boiler and still settings is a very dusty operation but was not included in this dust study as there was no work of this type in progress at any of the plants at the time of our survey. DOUJ 00*981 } MEASURES FOR REDUCTION OF THE DUST HAZARD 1. To suppress dust at the point of origin in such operations as rock-drilling;* handling, pulverising, and milling rock and ore; grinding metal on grindstones; abrasive-wheel cutting of granite and sandstone. 2. To prevent the re-dispersion of dust that has settled on the floors, walls, and other surfaoes such as in the granite indus try and in foundries. O o ro co cn G. - DESIGN EQUIPMENT TO CONTROL DUST - When new machinery or ether equipment is contemplated, the manufacturer can frequently be encouraged to include dust con trol features such as exhaust hoods as an integral part of the design and construc tion. E. - PROVIDE EXHAUST SYSTEMS - In some operations, ejdiaust systems may be installed to remove dust at its point of origin. In many cases several small systems are preferable to a larger system. Any mechanical ventilation system should be de sired to meet at least the minimum requirements of looal State laws or industrial codes, or lacking such requirements, should be installed according to the best ac cepted practice. Dust Arresters - Provision of dust arresters will prevent hazardous dusts from being circulated into other parts of the plant or into the neighborhood* The location of dust arresters is very important, particularly if dry types of arresters are used. Provision should be made for removal of the collected dust without its escape into the area where the arrester is located. * I. - ESTABLISH MAINTENANCE AND GOOD HOUSEKEEPING PROCEDURE - Good housekeeping is unquestionably the cheapest single method of controlling dust. Maintenance goes with it hand in hand. The best equipment in the world will not control dust if su perintendents, foremen, and workers are careless and disorderly in their work. Eight suggestions are advanced by the Conference Committee* 1. If dust-tight equipment is installed it should be inspected at regular and frequent intervals and all defects should be cor rected as soon as they are detected. 2. Operations should be performed in a manner that will create the minimum amount of dust. / 3. Use water under pressure where possible to clean building in teriors. 4. If practicable, oombine water with air for cleaning purposes. All cleaning should be done, if possible outside of working hours and men engaged is this operation should be provided with dust respirators. 5. Vacuum cleaning removes dust without dispersing it elsewhere. 6. Brushing is particularly adaptable for cleaning,buildings of the older type of construction. 7. Low-pressure steam can sometimes be used to advantage. 000982 ST00 I 2862 8. A responsible person should be assigned the task of supervis ing maintenance and housekeeping activities. Among other things he should make tests from time to time to make sure that the dust control program is achieving the desired re sults* J, - PROVIDE RESPIRATORS - The Conference Ccnsnittee was of the unaminous opin ion that "dust elimination must be gives primary consideration in solving the sili cosis problem". Nevertheless, when known methods of elimination are not applicable or are ineffective, respirators should be provided as "a last resort and for oc casional exposure only* Rotation of personnel under these conditions is advisable*1' The report definitely states that there will always be places where other methods will be inapplicable and ineffective, and respirators will be required for doing the work, also that there will be situations where respirators will be the primary means of protecting the workmen* The scope of good use of respirators is consider ably beyond that of occasional exposure* The need of rotating personnel depends on the type of work done and the supervision given the workmen. In seme operating, respirators are as much a part of the workman's equipment as his tools* Certainly, it cannot be expeeted that a person can wear a respirator for several hours con tinuously - but how many jobs are there that would require a person to keep the res pirator on continuously for an extended period of time* The common practice in the majority of industrial occupations is that the person is intermittently exposed and is afforded many'opportunities for the periodic removal of the respiratory protect tive device. The two general types of respirators which the Committee considered suitable for protection against silica dust are* \ (a) Air-purifying respirators that filter out the dust particles. (b) Supplied-air respirators in which dust-free air breathed by the worker cernes to him from an uncontaminated outside source* Host respirator manufacturers have submitted their devices for testing and approval by the U*S.Bureau of Hines, and only those which have been approved should be used* (a) Air-Purifying ^rpes of Respirators - Of the air-purifying class, the type most c07nrr.Qn.ly used is the mechanical filter respirator for mechanically-generated dust. These respirators give no protection from gases and vapors. They generally consist of half facepieces to which are attached an exhaust valve and a filtering medium that removes the dust from the inhaled air; some are equipped with a filter medium that removes paint mists and some fumes* They are light in weight and inex pensive* Filter pads must be changed at certain intervals, depending on the concen tration of dust. Some types restrict the field of vision. The general requirements of a safe and suitable Mechanical filter respirator are (1) adequate protection, (2) reasonable comfort and convenience, (3) an acceptable service life period of protec tion, (4) easy cleaning and sterilisation, and (5) low cost of maintenance in good serviceable condition. Studies of mechanical filtration by fibrous materials made by such agencies as the United States Bureau of Hines (U.S.Bur.of Hines, Tech*Paper No*394 (1926) and U.S.Pub.Health Bull.No.177 (1928)) and the Harvard School of Public Health (Journ. Indust.Byg. 9,26 (1927)) revealed that filtering efficiency varies with the particle size and the amount of solid particulate matter retained; also that the resistance to air flow varies with the amount of solid particulate matter retained and the rate of air flow. After all, the fundamental basis for judging the suitability of a respi rator is whether or not the amount of dust that is unretained or escapes through the filter under conditions of practical use is below the amount that would be harmful to breathe. This is net related to any percentage efficiency. In order to meet the Bureau of Hines requirements for approval, a respirator must satisfactorily remove DOW 00983 dusts of the following size charaeteristicss ST00I2863 99 95 90 80 70 per u n ti n cent n n n smaller it it n than 2, 80 .1. 80 it 1. 40 i it 1. 00 0. 85 microns >i n n tt 60 50 ti n ti ti n n tt 0. 72 0.60 n tt It will he noted that 80 per cent of the dust used in these approval tests is below one micron (l/25,OOOth of an inch) and SO per cent is below 0.6 microns. Canisters will not remove dusts of these characteristics and should not be used as dust respi rators. In order to obtain the desired protection, it is essential that the facepieces of the mechanical-filter respirators fit the face of the workman snugly but with a minimum of head-band tension. A simple practical test, suggested by Carlton E. Brown of the U. S. Bureau of Hines Experiment station in Pittsburgh, Pennsylvania (Jour. Indust.Byg. Feb. 1937 Vol. 19, Ho. 2, p, 98), that anyone ean run to determine whether a respirator facepiece is making a tight seal, is to wear it in a high con centration of coal dust. The time of the test can be shortened by blowing a stream of air containing a high concentration of coal dust around the edges of the facepiece. The location and approximate magnitude of the leaks are shown by streaks of coal dust on the part of the face covered by the faeepleoe. Another test, according to Hr. Brown, consists of plugging the intakes of the respirator and then attempting to inhale* This type of test could well be supplemented by the Coal dust test. (b) Supplied Air Respirators - Industrial processes such as pneumatic drillingyabrasive blasting and spray coating have introduced atmospheric conditions for which the air-purifying typo of respirators are not particularly suitable. Certain kinds of pneumatic drilling are responsible for dust concentrations so high that they would rapidly overload a dust respirator. The operator of an abrasive blasting outfit must be protected not only against the inhalation of air containing high concentra tions of dust, but also against impact and abrasion of the head and shoulder by the rebounding abrasive and loosened abraded material. Spray coating is responsible fre quently for pollution of the surrounding abaosphere by a combination of particulate matter (mists that are liquid particles or a combination of solid and liquid par ticles) and haraful vapors resulting from the evaporation of the liquid vehicle of the coating used in the spray gun. Since these operations are carried out frequently in isolated places and at different locations at various times, they do not lend themselves always to general control measures. Therefore, supplied air respirators perform a definite service. The types In general use are those commonly known as hose masks, air-line respirators, and abrasive blasting respirators such as sand blast masks, helmets, and hoods. Suppiied-air respirators have the following advantages for routine non-emer gency use over those of the air-purifying respirators such as gas masks, mechanicalfilter respirators and the combination of gas mask with a mechanical filters 1. HO resistance to inhalation. 2. Freedom from inward leakage of contaminated air. 3. Protection against all kinds of contaminants and even against at mospheres deficient in oxygen which will not poison or irritate the skin. DOW 00984 ST00I2864 4. The Inflowing air reduces excessive perspiration and tends to cool the face, 5. When a hand-operated blower is used a second person is always present. (With an approved mask, provided the facepiece is tight, the wearer can inhale enough air through the hose to es cape if the blower should stop). The Air-Line Respirator consists of a tight-fitting facepiece, a loosely fit ting facepiece or even a helmet or hood covering the head and extending down over the neck or shoulders. The air supplied to these respirators has been largely that ob tained from the compressed air source used in the performance of the work, as in sand blasting, pneunatic drilling and spray painting. This air is frequently con taminated with objectionable and, in some instances, harmful substances which, to some extent, can be removed by means of air-purifying appurtenances. In discussing "Res piratory Protective Devices" in the February (1937) issue of the Journal of Indus trial Hygiene and Toxicology, Hr. C. E. Brown of the United States Bureau of Hines wrote: "Using air from the ordinary compressed air system found in industry to supply respirators is not to be indiscriminately reccnmended. These oompressed air systems are usually of the higih pressure, internally lu bricated, reciprocating-ccmpressor type. The air' supplied by these systems is contaminated frequently with malodorous constituents such as vapors, mists and products of decomposition of the compressor lu- \ brieant, slugs of water, and rust from the pipe line. All or most of these contaminants can be removed probably by some of the commercial air purifiers sold for this purpose. A pressure-reducing mechanism should be used also in the line to prevent any possibility of sudden accidental blasts of higlwpressure air from injuring the lungs of the wearer of the respirator. With a compressor of this type there is always the possibility, however rare it may be in well-kept systems, of the generation of carbon monoxide due to overheating of the compressor lu bricant (Jour, Indust.Eyg. 18,461 (1936)). This danger earn be minimised or eliminated by the use of temperature controls or carbon monoxide alarms on the compressor which, of course, should be so maintained as to pre vent the generation of carbon monoxide. "The trend in supplied-air respirators is to use special low-pressure, externally lubricated, positive-pressure air-supply devices. Host of the objections to the high-pressure reciprooating-type cempressor do not apply to an air-supply of this kind. Since these devices are not eoam in industry, however, it is usually necessary to purchase a special one for use with the respirator. 'Since air purifiers, pres sure-reducing mechanisms, and special compressor-control or alarm me chanisms are not necessary, the price of this respirator complete with air-supply device should not exceed that of the other type of respira-. tor without the air supoly system. "The use of a special air-conditioning unit to regulate the tempera ture and humidity of the air supplied to the respirator wearer is de sirable. " The minimum air supply for a respirator designed to use all the air for res piratory needs at a high degree of efficiency is generally agreed among Industrial Hygienists to be,at least four to six times the air breathed per minute. As a general class, respirators with loose-fitting facepieces, hoods, or helmets require DOW 000985 / <r. / nore sir than those with tight fitting facepieces. There is seme difference of opinion among users of respirators as to vhether or not adjustments should be provided whereby the wearer can vary the flow of air to meet variations in his requirements. It was the opinion of the National Silioosis Conference Committee that definite reconmendations for all situations cannot he made, but for many situations, and particularly where tight-fitting facepieces are used, an adjustable flow is desirable and may even be necessary) also, most worimen con learn to adjust the air properly. On the other hand fixed-flow procedures re quire a minimum amount of instruction and supervision and are the most conducive to safety under all conditions. ST00I2865 While-Hose Masks and Air-Line Respirators have many definite advantages the area of travel of the wearer is limited to the length of the hose, and movements are handicapped to some extent by the hose. Manifestly, the air for the hose and the mask should be fresh and pure, but unfortunately this is not always so. Abrasive Blasting Respirator - Abrasive blasting respirators consist essen tially of a hood, with windows, that fits loosely over the head and shoulders and designed to withstand and protect the wearer's head, seek and shoulders from abra sion by the rebounding of partloles of sand or grit) and a supply of fresh air, at. least six cubic feet ner minute, blown into the hooi Only equipment which has met the United States Bureau of Mines test requirements and v&ieh is approved by the Medical and Safety Departments should be used, * (c) Acceptance and tTse of Personal Respiratory Protection by WflfVman - As stated In a paper by G. M. Hints and H. C, Fowler of the United States Bureau of Mines (I.C.6915 No.vl936) presented at the International Petroleum Exposition and Congress, Tulsa, Oklahoma, May 21 1936, selecting respiratory protective equipment is simple compared with getting men to wear it after it is supplied. Generally worbaen will wear masks readily in places where they have seen others asphyxiated, or in some similar trouble, but they are likely to resist wearing protective equipment where the dust cannot be seen or where the fuses and mist have no objectionable odor. There are three main reasons for such resistances First, Inbred objection to any new idea; Second, the feeling that the individual is a superman and can ''take it" without protection; end. Third, the inconvenience of wearing the equipment. In a survey conducted among the employees of the Col gate- Palmolive- Peet Com pany by Mr, F. H, Wallner of that Company's Insurance Department, it was found that the men didn't like the disfiguring appearance of a "mu2rle" over their faces. This survey also disclosed that some workers objected to the respirator because they thought it made breathing difficult when the real trouble was that they were not breathing correctly. Breathing through a respirator should be done deeply and slow ly and after the proper habit has been acquired much discomfort may be eliminated. Quoting Mr. Wallnert DOW 00986 "Foremen should appreciate that the position of the straps that hold the respirator in place has much to do with comfort. They should learn whether the straps should be worn over the head or around the neck. Seme types' have two straps, one to be worn around the neck, the other around the head." Frobably the most effective plan in getting respirators worn is first to "sell" STOOl2866 the supervising personnel who in turn should "sell" the worker by education, possibly accompanied by strict and fair supervision and discipline. Employees exposed to dust hazards requiring the wearing of respirators should be convinced that it is essential to sacrifice some comfort and dignity to avoid serious cases of disability and suffer ing. Every worker should have his own respirator. It requires time and effort to adjust this protective device so it contacts the face snugly with a minimum of headband tension. It cannot be expected that the average workman will readjust a dif ferent respirator each day. Also, the psychological effect of using a respirator worn previously by another workman is not unimportant. Although he may not say any thing about it, it is naturally revolting to most men's principles of bodily sani tation to have to elaap over his face a device that has been soaked with sweat and dirt of another man's face and into whioh one or more men have breathed day after day! It is too much like using the other fellow's tooth brush. Ihe best practice is to mark every respirator so each workman can identify his own. (d) Use. Malnter*wfte and Care of Respirators - Personal respiratory protective de vices must be maintained in a condition substantially the same as when received frau the manufacturer. Depending on the density of the dust replaceable filters should be changed frequently to prevent their becoming clogged and usually it is desirable to use a respirator without a facelet. However, if they are considered necessary, the faeelets should be changed often to avoid skin irritation. A clean facelt gives the respirator a clean appearance and removes one objection to wearing it. The Colgate-Palmolive-Peet Campary found that the habit of seme workers of removing their respirators at intervals oaused skin irritation. Everytime they did* this,, dust settled on the surfaces that lay next to the worker's face and Irritating particles were transferred to the skin when the devlee was replaced. It is, there fore, best to have the employee wear his respirator constantly while under exposure. In some cases, ointments or petrolem jelly has helped to overcome the irritating ef fect of points that contact the skin. Where a considerable number of respirators are used, it is good practice to have a "Respirator Room" with an attendant who issues the respirators and cleans, sterilises and otherwise keeps them in good condition. Respirators may be cleansed by washing and brushing them with an antiseptic soap and warm water. They should be checked for damaged or improperly functioning parts sueh as rubber valve seats er.a head-bands. If defective, these should be replaced by new parts. WHAT MEDICAL CONTROL SHOULD EE EXERCISED IN THE SELECTION AND SUPERVISION OF MEN WORKING ON DUSTY JOBS? - It is essential that adequate medical control be ex ercised. Such control should include the examination, prior to initial working or. dusty jobs of the worker to insure that he is a suitable physical subject. This ex* amination should preferably include X-ray examination of the lungs which permits closer control with subsequent X-ray tests as well as being a protection to the em ployer in the event of axy later legal action. A worker, to be classed as pfysic&lly suitable, should be in addition, de termined to be a nos ^-breather rather than a mouth-breather and the natural filter ing capacity of the hose should be found to be satisfactory. G. Lehmann (J.Ind2yg* 17,37 - 1935) indicates that the "Silicotic susceptibility of workers with poor na sal filtration is much greater than that of men with good nasal filters". He ad vises that jobs with a silicosis hazard be held only by men with good nasal filters" and that mouth breathers are an especially bad risk. He suggests that the "dust re taining capacity of the nose be used as an index of the individual's qualification for working in a silicosis producing atmosphere". It is possible that Sternsteis's technique for measuring nasal resistance ("Industrial Dusts - p.65) could be developedinto a simple procedure for selecting men best adapted to dust exposure. According to Drinker and-Hatch ("industrial Dust" p.32) it is wise to select DOW 00987 ST00I2867 for dusty jobs men who are p&st the age of 40 and not young men just taking up a trade. All workers engaged in hamful dusty operations should be periodically thor oughly re-examined, including X-ray tests. Particular emphasis should be placed on any indication of shortness of breath and chest pains Regulations should be enforced concerning the time limitation of work of .asy maployees involved in a dust producing operation. Such Company regulations concern ing sandblasting calling for a fixed six-month maximum period on such work, after whioh a minimum six-month period away from dust producing work should be followed more closely* For protection from a legal angle, the worker should be given a final thor ough examination including X-ray before being permanently transferred to seme other type of work, laid off or discharged* CONCLUSION There is still a tremendous amount to be learned about pneumoconiosis ***** dust-producing operations* One thing, however, is certain -there is a very definite tendency to require compensation for industrial or occupational diseases. If these compensation costs are to be kept to a minimum and the health and safety of workman ' are to be promoted it will be necessary to make further studies and to promptly adopt adequate precautionary measures. Many of these are now in effect, the others should be'put in force as soon as possible. After years of study end direct contact , with the Dust Problem, Mr. Dan Harrington, Chief, Health and Safety Branch, United States Bureau of Mines, has came to this conclusion (Eng, & Min. Jour* March 1937 pps, 119-21) with which we are heartily in aocord "In the mate of uncertainties connected with almost all phases of the causation and diagnosis of dust disease, about the only really well-determined fact available is that breathing large quantities of du6t (or possibly of certain dust) over extended periods is likely under seme conditions to be harmful to health and that subsequent al leviation or cure is difficult or impossible. Therefore, it would seem to be logical to try to prevent dust formation thus preventing it from harming workers through respiration or otherwise. Here is a real job for the engineer, and little or no help can be expected in these vital functions from any agency except the engineers and operat ing officials. "The most harmful of the ordinary dusts to breath Is probably silica dust, but, on the other hand, not even free silica, supposed ly the most detrimental of the silica dusts, is harmful unless it is breathed, in considerable quantities end over extended periods. Ho human being ever lived any considerable time on this earth of ours without breathing silica dust (free silica dust), yet by no means all of the people of the world have or have had silicosis. In other words, the quantity of dust taken into the respiratory organs is a controll ing factor in dust respiratory harmfulness. "One ccastor-sense answer is that any atmosphere in which dust is visible to the naked eye is certainly too dusty to be breathed with safety by human beings, and the wise, farsighted, human employer will immediately start to decrease the dust content in any atmosphere where dust is risible. After he has eliminated visible dust, there may DOW 000988 ST00I2868 still remain enough very small invisible dust to cause harm to the health of those who breath it,, but in any event if he has exerted suf ficient well-directed effort to remove the visible dust it is certain that much of the smaller invisible, and probably most harmful dust has also been removed. + "Manifestly, if dust is kept out of the air breathed by workers, the latter oannot sucoumb to dust disease of a respiratory character." In closing, we acknowledge with gratitude the support and cooperation of Dr. W. J. Denno, General Medical Director, Standard Oil Company (New Jersey) whc vision and active interest is Medis^Safety problems made this Dust Study possib We also appreciate the advice and assistance rendered by* Mr. V. ?. Yant, Director of Research ie Development, Mine Safety Appliances Company, Pittsburgh, Pennsylvania. Dr. Leonard Greenburg, Executive Direotor, Division of Industrial hygiene. Department of Labor, State of New York, New York, N.Y, Dr. R. R. Sayers, Senior Surgeon, U.S. Public Health Servioe Chief, Division of Industrial Hygiene, National Institute of Health, Washington, D. C. Mr. Daniel Harrington, Chief, Health and Safety Division United States Bureau of Mines, Washington, D. C. Dr. A. J. Lanza, Assistant Medical Director, Metropolitan Life Insurance Company, New York, N.Y. Mr. E, E. Barlow, Chief Engineer, Standard Oil Development Company, Elisabeth, New Jersey. Mr. H. N. Blakeslee, Department of Accident Prevention, American Petroleum Institute, New York, N.Y. New York, N.Y. July Fifteenth 19 3 7 R. S. Bonsib Chief Safety Inspector Standard Oil Co. (N. J. ) DOW 00989 ! I. i i: ITEM * 3 Thirty-five Years of TtVs 1. ThevalueforMicadu$tshallbe20M.P.P.C.F. 2. The value for Radium 226 in air shall be 6 X 10*4 micro curies per cubic meter. 5. The value for Polonium 210 in air shall be 1X10* micro curies per cubic meter. Committee members: W. Q. rredrick. Chairman K. E. Charron K. E. Markuson Arthur Vorwald 1952 changes from 1951 The following new threshold limit values are recommended for addition to the 1951 list (MV). Cresoi........................................................... ' Diethyl amine....................................... Ethyi amine.................................................... Methyial ........................................................... Phenol 5 ppm 25ppm 25ppm 1000 Deletions Radon (curies per cubic meter) ............................. Thoron (curies per cubic meter)........................... Radium 226 (microcuries per cubic meter) .................................................................. Polonium 210 (microcuries per cubic meter) .................................................................. 10* 10* 10* 10* Committee members: Allan L Coleman. Chairman D. H. Byers LT.Fairhall Kingsley Kay Arthur j. Vorwald Lf. Weller "Values are given In the following tables for the madmum average atmospheric concen tration of contaminants to which workers may be exposed for an eight-hour working day without tyusy to health. "These values are based on the best avalIable Information from Industrial experience, from experimental studies and. when pos sible. from the combination of both. They are not fixed values, but are reviewed annually by the Committee on Threshold limits for changes, revisions or additions as further information becomes available. Threshold limits should be used as guides In the control of health hazards and should not be regarded as fine Unes between safe and dangerous concentrations. They represent conditions only within which U Is felt that workers may be repeatedly exposed, day after day. without adversely affecting their health, it 15* felt at the present Ume. that workers should not be exposed to a working environment contain ing any of these substances in excess of the uaiue indicated." New Values 12-Dibromoethane (ethylene dibromide) -- 25 ppm riuorme (gas) -- 0.1 ppm 1.1.1-Trichloroethane (methyl chloroform) -- 500 ppm 0.0-Dfethyl-0*p*nitrophenyt thiophosphate (parathion) -- 0.1 ppm Uranium (soluble compounds) -- 0.05 mg/m3 Uranium (insoluble compounds) -- 0.25 mg/m3 Revised Values Acetone --1000 ppm Carbon tetrachloride -- 25 ppm 12-Dlchloroethane (ethylene dichloride) -- 300 ppm TetracMoroethylene -- 200 ppm Trichloroethylene -- 200 ppm 1953 changes from 1952 The following is the first proposed preface for the MAC values. Committee members: Allan L Coleman. Chairman William L Ball L T. Falrhali Kingsley Kay II. E. Stokinger A. J. Vorwald Louis r. Weller DOU 00990 rc x* Ann. Am. Cortf. InO. Hu4. Vot9ii' l4Ak)k-i* ITEM * 4 ST00I2870 ASBESTOS ;- CM: 1332-21-4 TLV-TWA, Appendix Ala -- Rccogniz.' luirun Carcinogen Amosite CAS: 12172-73-5 TLV-TWA, OJ Cber/cc* Chrysotile CAS: 12001-29-5 TLV-TWA, 2 f&en/cc* Crocidofite CAS: 12001-26-4 TLV-TWA, 0.2 fiber/cc* Other forms TLV-TWA, 2 a*fS/cc- According to recent mineralogical definitions,'" asbestos a: ~J) A colleaive mineratogicai term encorrtpasjtng the asbestiform varieties of various minera/s; 2) An industrial product ob tained by mining andprocessing primarily asbestiform minerals*" For the purpose of considering a recommendation for a threshold value of asbestos dust in the workplace, only the second definition above is applicable. Although there are four types of natural min eral fibers that have been in industrial use, only three have been used in the United States: chrysotile, amosite, and crocidolite. The fourth, anthophyliite, is mined and used in Finland. Of the three types of asbestos that have been used in North America, Canadian ehryjotiie has formed 95% of alt natural mineral fibers used, with amosite and crocidolite (both imported from South Africa) constituting the other 5%. It sliould be noted that chrysotile is classified as a serpen tine mineral, whereas the other three types of asbestos are amphiboles. It is now generally recognized that excessive inhalation of asbestos dust causes chronic inflammations of lung tissue and pleural mem branes as well as cancers. Whereas identification of asbestos dust as a cause of fibrosing inflammation of lung tissue occurred as early as 1907,'J* it was not until 1930 that a more definitive study by Merewether and Price'*' resulted m the regulations which greatly im proved hygienic conditions in abestos factories in the United Kingdom. The development of lung cancer in asbestos workers, first reported by Wood and Gloyne** in the U.K. in 1934 and by lynch and Smith'1* m the U.S. in 1935, was not firmly established until 1955 by the publication of Dolt** of a study of workers in an Eng lish asbestos textile factory, and in the United States by the paper of Selikoff er at* in 1964 concerned with cancers in insulation wor kers. in I960 the relationship between the inhalation of asbestos dust and mesothelioma was demonstrated by Wagner et al.* Asbestosis is a diffuse but nonuniform fibrosis of the lungs that is generally most severe in the basilar portions. As a result of the fibro sis some of the airspaces (alveoli) are not perfused with blood and alveoli that are perfused with blood may not be adequately venti lated because of stiff, thickened alveolar walls. The fibrosis makes the lungs less compliant, thereby increasing the energy requirement * F>h*n tanget than 5 timjfldtmh an atfaet ratio equal to or greater than J l at deterbv (he membrane filter method at 40CMS0X marulcjt<m U-mm objective! saw* enruraw JJwmmjdon 40 of breathing. There is increasing impairment in diffusion of gases lead ing to increasing breathlessness. It is not uncommon to find thickening of the visceral pleura, some times very severe, by extension of the parenchymal inflammation. This causes an additional increase in the effort of breathing. The parietal pleura may show patches of severe thickening, par ticularly over the diaphragm and the lower portions of the chest wall -- resulting in the so-called pleural hyaline plaques. These may be come visible in X-ray films of the chest -- particularly, if they be come impregnated with calcium salts. Such pleural plaques may develop from asbestos exposure in the absence of asbestosis. They cause no symptoms. A study of the members ofan asbestos insulators union published in 1964 revealed that deaths from lung cancer in this population was much greater than expected.m A later investigation published in 1973 by Hammond and Selikoff of a much larger number of these worker* (17,800} showed that nearly all cancers occurred in cigarette smokers.4* The conclusion of these authors was as follows: "Itseems dear, then, that lung cancer is uncommon among as bestos insulation workers who have no history ofcigarette smok ing, and that if the risk is inoeased such an increase is not great." The total lung cancer rate in this cohort of workers was 4.8 times the expected. The asbestos insulators who had a history of cigarette smoking had a lung cancer rate 5.4 times the expected rate; but com pared to the lung cancer rate of the nonsmoking workers, the smok ing insulators' lung cancer rate was 14 times greater. * All types of asbestos are known to cause the inflammatory changes in the kings and pleurae described above and lung cancer. However, there is experimental and epidemiologic evidence that there may be differences in the potential of the different asbestos types to produce disease. Thus, it has been suggested that crocidolite has the greatest potential to produce disease; chrysotile, the smallest; with amosite occupying an intermediate position."* In a study of 1348 retirees from the asbestos industry by Emeriine and Henderson/1" the respiratory cancer rate of men exposed only to chrysotile was 2.4 times the expected, whereas this rate was 5.3 times the expected for men who had been exposed to a combination of chrysotile and crocidolite. In the asbestos cement industry a simitar difference was observed. Workers exposed only to chrysotile and cement (shingles and sheets) had a respiratory cancer rate of 1.4 times the expected, whereas workers exposed to both, chrysotile and crocidolite and ce ment (asbestos cement pipes), had a respiratory cancer rate 6.1 times the expected. Mesotheliomas are rare, usually rapidly fatal cancers that originate from the surface lining the chest or abdominal cavity. From 1960 through 1975, 4539 mesotheliomas have been reported world wide.'"' The vast majority of these cancers were in people exposed to crocidolite alone or in combination with other types of asbestos. McDonald and McDonald'"' tabulated those reports of mesothe lioma where the type of asbestos exposure was known. Although the number of such cases is small, where the exposure was to crocido lite alone or in combination with other types of asbestos, death from mesothelioma constituted 6.1% of the deaths from all causes, with a range ol 2.42% to 16.07%. in contrast, deaths from mesothelioma in workers exposed only to chrysotile constituted only 0.3% of the deaths from all causes, with a range of 0.24% to 0.87%. An even greater contrast i> found in the Finnish statistics of workers exposed to anthophyliite. Meurman et at'" investigated 216 deaths that oc curred among approximately 900 miners and millers of anthophyl- file during the 32-year period 1936-1967 and found not one case of mesothelioma. * OOU1 000991 ST00I287I 1 / 2-9 ^Z21- 27 \ The Work Environment of Insulating Workers J. UROY BALZER and W. CLARK COOPER, M.D. Divuton of Environmental Health Sciences, School of Public Health, University of California, Berkeley, California 94726 With the cooperation of the asbestos worker*' aiuoa and insulating contractors, a stody 8 being made of the environmental exposures and the health of insulating workers in the western United States. Survey* have been made In a number of work situations, Including small commercial buildlog, major industrial construction and marine operations. Major emphasis has been on exposures to asbestos-containing materials, fiber glass, cork, plasties, and adhesives. Trends in produet usage are presented, as well as illustrative dust counts, based on membrane filter and irapingcr samples, for various components of the insulator's job, c.g., prefabrication, applica tion, finishing, mixing and tearing out of old insulation. s-r'O' i .t* Introduction YOTORKERS IN THE insulating trade W make up an occupational group known to have exposures to asbestos that are varied and difficult to control. .In recent years, in vestigators have shown that the relationship between asbestos minerals and human disease extends beyond a disabling pneumoconiosis produced in some workers. Evidence has ac cumulated that asbestos workers have a high er incidence than average of malignancies of the lungs, pleura, and peritoneum. Asbestosis in insulating workers has been reported in England by Ellman1 in 1934 and by Leathart and Sanderson2 in 1963; in the United States by Fleischer et ol.s in 1946, Pendergrass4 in 1958, Marr* in 1958, and by Selikoff et el.* in 1964; in Sweden by Ahlmark et et.1 in 1960; and in Finland by Ahlman* in 1966. Selikoff* reported lung cancer than expected incidence of lung cancer in ;V ^ California; and Keane and Zavon** m 1966 ^ in their descriptive report of the insulating y, trade in Cincinnati also described an exeess .: of lung cancer. Because asbestos may be a widespread en- f\ vironmental contaminant and the established threshold limit may need re-examinatipn, there is need for a thorough appraisal of the; work environment of the insulating worker. We are now in the process of doing a study of. . San Francisco area insulating workers in order ^ to determine the incidence of pneumoconiosis and malignancies and make observations and measurements on the work environment. This v report summaries our preliminary environ* mental findings on the materials used, meth ods of application, and dust and fiber con centrations. deaths in insulating workers in New York- \ Background Information en Union Membership New Jersey to be over six times expected; This study was made possible by the whole Tht* w MMeneC br Rciearch Grant OH- 00304, {tea th* Public Health Service, U. S. Department f Health. Education and WeUarc and received preliminary Mppon Item General ReturcJt Supiwrt Gram l-SOl-FR- 04*41. Public Health Service. U. S. Department { Health. Education and Wellare. Thh report vai presented at the American Industrial Hrtxne a-aociatiun Conference in Chicago, llliuur,. on Mar S. 1967. hearted cooperation of the International Ass ociation of Heat and Frost Insulators and Asbestos Workers (both from their national headquarters and from the officers of their various locals), and by insulating contractors, individually and through the Western As* ' j < ITEM # 5 DOW 00992 ST00I2872 2:6 Mcy~]ur.c. 1 Table V Bus; Concentrations Based on Impinger Samples by Job Classification Job Claaaificaiien Prefabrication Application Finishinc Tearine out Mixine Ceneral Number of Samples Mean 1175 63..55 89 52..26 C 9 91..14 mppef Median 422511......154844 Range 0021....8852----28868..226.8 02..68--11.68.C Tauix VI Fiber Concentration Based on Membrane Filter Samples by job Classification job Classification Prefabrieatien Application kimsiunc Tcannc out Mixing General Number of Samples Mean 4252 31 211276 46282r.....s46798 Fibers/ee Median 81..44 40..98 1.4 0.8 R* 0.1 0O..1t 0.2 0.2 0.1 American Industrial Hygiene Association Journal May-June, 1968 1 i 227 States industries where asbestos exposures oc- possibility that other components of the in cur, chrysotile asbestos has not yet supplanted sulating materials may be synergistic. The \ the use of amosite asbestos in the manufac- incidence of pneumoconiosis in these work turing of insulation materials. Amosite ex- ers, the need for better environmental con * posures are the most significant in the in* trol measures, and medical surveillance will sulating trade. be the subjects of more detailed later reports. :\i The breathing-zone dust levels found in the dustiest operations observed were not as References high as the incidence of pneumoconiosis * niay have led us to expect. Some sample .V areas exceeded the present threshold limit r; value (TLV) recommended by the ACGIH, : however, these samples were not for extended ' periods of time. Although we attempted to J. Eilmam, ?.: Pneumoconiosis: Part III. Pulmonary Aabestosss. Brit. J. Radiol. 7: 281 (19341. 2. Leatha*t. C. L,, and J. ?. Sakscjuov: Seme Observelion* os Asbestotis. Ana. Oeettp. Hyg. 8: 65 (1963). 2. Flusates, W. E-. F. J. Viutf, R. J. Glads, and P. Dsinkss: A Health Survey of Pipe Cm^ering Operations in Constructing N*v*i Vessels. J. Induct. Hyg. & To* 28: 9 (1946). . :r sample the dustiest operations, the timeweighted averages for dust samples contain- 4. PcKpcsotASS, E. P.: Silicosis and a Few of the Other Pneumoconioses. Amtr. J. Roentgenol. Radium Therapy Hurt. Med. 80: 1 (1958). mg asbestos would probably not exceed the i. M*ae. \V. T.: Asbestos Exposure Durinc Naval Vse! Overhaul. Amet. Indiut. Hyg. Auee. J. 25: 264 (196-4) ... TLV in most situations, even on ships. This 6. SuiKorr, 1. J., J. Chvhc, and E. C. Hammoso: Asbes- 4. conforms to findings by Fleischer et al.t* by to* Exposure and Neoplasia. JAMjt. 188: 22 (1964) 7. Ahlmabk, Axel, T. Bauct, and A. Nystxom: Silica:: =. Mnrrs and by Leathart and Sanderson2 and and Other Pmenmoeoniote* ix Swtdcn. pp, 353-35'. Scandinavian University Books, Stockholm, Sweden to recently reported findings by Ferris*1421w*5h4o* 6 7 8 9(I9*601)1. 12 13 last year reported studies in the same ship- /- yards earlier appraised by Fleischer.2 The present TLV for asbestos was recom- i ;*' mended by Drecssen et a/.13 in 1938, after i ' * epidemiologic studies in textile mills using chrvsotilc asbestos. It was not intended for 8. Ahlmam, K.: Asbcuons Amonf Insulating; Workers in Finland. Proceedingt of the 14lh Internationel Conguii aa Occupational Health, pp. 237-240, Vienna. Austria (Sept. 1966). 9. Dukn, J. E., and J. M. Warn: Cancer Experience of 1 Several Occupational Groups Followed Prospective!' Amtr. J. Public Health 55: 1367 (1965). !0. Keane, W. T., and M. R. Zavon: Occupational Harards o( Pipe Insulators. AMA Arch. Environ. Health 13: 171 (1966). `.extrapolation to all forms of asbestos use under all circumstances of exposure. The . proven occurrence of pneumoconiosis in in sulating workers exposed intermittently as * described in this paper and by the authors *r previously cited suggests that the TLV for asbestos is too high. Our studies are, how. ever, not ye; complete enough to warrant a :- final conclusion. We cannot eliminate the 11. Coorca. W. C., and I. R. Tabshaw: Unpublished Material (1966). 12. Eowaads. C. H., and J. R. Lynch: Tlie Method Used by the U. S. Public Health Service (or Enumeration o) Asbestos Dun on Membrane Filters. Unpublished (1966;. 13. TistMRLL, V.: The Inhalation of Fibrous Dusts. Ann. A', i'. Acad. Sti. 132: 255 (19651. 14. Fnxais. B-: Personal Communication (1966). 15. Daujsen. W. C-, J. M- Dau> Valle, T. I. Eow**ps .1. M. MtLtxa, and R. R. Save**: A Study ol Athene:.* in the Aibettei Textile Industry. Public Healtli Bullet::' No. 241. U. S. Govt. Printing Office, Washington. D. C. (1938). Received June 20, lfK>" 00993 DOW