Document km728OO77nb81dMEgEVvgVBOq

I Lead Industries Association, inc. Zinc institute, Inc. 292 Madison Avenue, New York, N.Y. 10017 Philip E. Robinson Executive Vice Pretitient (212) 679-6020 September 18, 1972 To Members of the Executive Committee of LIA Board of Directors Dear Mr. Craig: SUBJECT: Draft - Environmental Health Committee - Policy Document The attached draft is for your review and comment and reflects the consensus of LIA's Environmental Health Committee at its meeting in Trail, B.C., in mid-July. The document, after review by you and members of the EHC, will be submitted to the Occupational Safety & Health Administration as the lead industry's policy position. We-hope - indeed expect - that OSHA and NIOSH will give serious consideration to the lead producing and using industries' recommendations as they prepare their final criteria document. We have also submitted the paper to legal counsel (Debevoise, Plimpton, Lyons & Gates) for review and comment. Members of your environmental staff were either in attendance at Trail or have subsequently received the document. You may wish to talk with them about it. In any event, we would appreciate your comments as soon as possible. Sincerely, PER:lm Enclosure cc: Mr. Dr. Mr. J. F. Smith J. F. Cole J. L. Kimberley Philip E. Robinson Executive Vice President T \ -' LI AC3786 hZ - .AKT Lead Industries Association, Inc. Zinc Institute, Inc. 292 Madison Avenue. New York, N.Y. 10017 (212) 679-6020 Philip E. Robinson Cvect/tfvw Vic Prnidtnt September 18, 1972 To Members of the Executive Committee of LIA Board of Directors Dear Mr. Smylie: SUBJECT: Draft - Environmental Health Committee - Policy Document The attached draft is for your review and comment and reflects the consensus of LIA's Environmental Health Committee at its meeting in Trail, B.C., in mid-July. The document, after review by you and members of the EHC, will be submitted to the Occupational Safety & Health Administration as the lead industry's policy position. We hope - indeed expect - that OSHA and NIOSH will give serious consideration to the lead producing and using industries' recommendations as they prepare their final criteria document. We have also submitted the paper to legal counsel (Debevoise, Plimpton, Lyons & Gates) for review and comment. Members of your environmental staff were either in attendance at Trail or have subsequently received the document. You may wish to talk with them about it. In any event, we would appreciate your conments as soon as possible. Sincerely, PER:lm Enclosure cc: Mr. Dr. Mr. J. F. Smith J. F. Cole J. L. Kimberley Philip E. Robinson Executive Vice President LlAc??89  - ,* - Lead Industries Association, Inc. Zinc Institute, Inc. 292 Madison Avenue, New York, N Y. 10017 Philip E. Robinson Ex*cu1<r* Vic* Pr**id*nt (212) 679-6020 September 18, 1972 To Members of the Executive Committee of LIA Board of Directors Dear Mr, McCullough: SUBJECT: Draft - Environmental Health Committee - Policy Document The attached draft is for your review and comment and reflects the consensus of LIA's Environmental Health Committee at its meeting in Trail, B.C., in mid-July. The document, after review by you and members of the EHC, will be submitted to the Occupational Safety & Health Administration as the lead industry's policy position. We hope - indeed expect - that OSHA and NIOSH will give serious consideration to the lead producing and using industries' recommendations as they prepare their final criteria document. We have also submitted the paper to legal counsel (Debevoise, Plimpton, Lyons & Gates) for review and comment. Members of your environmental staff were either in attendance at Trail or have subsequently received the document. You may wish to talk with them about it. In any event, we would appreciate your comments as soon as possible. Sincerely, PER: lm Enclosure cc: Mr. J. F. Smith Dr. J. F. Cole Mr. J. L. Kimberley 1 J Philip E. Robinson Executive Vice President LI AC 37 90 Pb'SSB Lead Industries Association, inc. Zinc Institute, Inc. 292 Madison Avenue, New York, N.Y. 10017 (212) 679-6020 Philip E. Robinson jrcvtfv Viet Prtsidwit September 18, 1972 To Members of the Executive Committee of LIA Board of Directors Dear Mr. Strauss: SUBJECT: Draft - Environmental Health Committee - Policy Document The attached draft is for your review and comment and reflects the consensus of LIA's Environmental Health Committee at its meeting in Trail, B.C., in mid-July. The document, after review by you and members of the EHC, will be submitted to the Occupational Safety & Health Administration as the lead industry's policy position. We hope - indeed expect - that OSHA and NIOSH will give serious consideration to the lead producing and using industries' recommendations as they prepare their final criteria document. We have also submitted the paper to legal counsel (Debevoise, Plimpton, Lyons & Gates) for review and comment. Members of your environmental staff were either in attendance at Trail or have subsequently received the document. You may wish to talk with them about it. In any event, we would appreciate your comments as soon as possible. Sincerely, PER: lm Enclosure cc: Mr. J. F. Smith Dr. J. F. Cole Mr. J. L. Kimberley Philip E. Robinson Executive Vice President LI A03791 . -7 - * ' `` r*.'' * - * -A * - `1 ' ^* *, .T VI'98 Lead Industries Association, Inc. Zinc Institute, Inc. 292 Madison Avenue. New York, N.Y. 10017 (212) 679-6020 Philip E. Robinson Extcutrw Vic President September 18 , 1972 To Members of the Executive Committee of LIA Board of Directors Dear Mr. Kenny: SUBJECT: Draft - Environmental Health Committee - Policy Document The attached draft is for your review and comment and reflects the consensus of LlA's Environmental Health Committee at its meeting in Trail, B.C., in mid-July. The document, after review by you and members of the EHC, will be submitted to the Occupational Safety & Health Administration as the lead industry's policy position. We hope - indeed expect - that OSHA and NIOSH will give serious consideration to the lead producing and using industries' recommendations as they prepare their final criteria document. We have also submitted the paper to legal counsel (Debevoise, Plimpton, Lyons & Gates) for review and comment. Members of your environmental staff were either in attendance at Trail or have subsequently received the document. You may wish to talk with them about it. In any event, we would appreciate your comments as soon as possible. Sincerely, PER: lm Enclosure cc: Mr. J. F. Smith Dr. J. F. Cole Mr. J. L. Kimberley Philip E. Robinson Executive Vice President < LIA03792 A - v, jC ' v. FL'K Lead Industries Association, Inc. Zinc Institute, Inc. 292 Madison Avenue, New York, N.Y. 10017 Philip E. Robinson Exocutirw Vk Prtsidftt trX-- A-.y (212) 679-6020 September 18, 1972 To Members of the Executive Committee of LIA Board of Directors Dear Mr. Whitson: SUBJECT: Draft - Environmental Health Committee - Policy Document The attached draft is for your review and comment and reflects the consensus of LIA's Environmental Health Committee at its meeting in Trail, B.C., in mid-July, The document, after review by you and members of the EHC, will be submitted to the Occupational Safety & Health Administration as the lead industry's policy position. We hope - indeed expect r that OSHA and NIOSH will give serious consideration to the lead producing and using industries' recommendations as they prepare their final criteria document. We have also submitted the paper to legal counsel (Debevoise, Plimpton, Lyons & Gates) for review and comment. Members of your environmental staff were either in attendance at Trail or have subsequently received the document. You may wish to talk with them about it. In any event, we would appreciate your comments as soon as possible. Sincerely, PER: lm Enclosure cc: Mr. Dr. Mr. J. F. Smith J. F. Cole J. L. Kimberley Philip E. Robinson Executive Vice President Lead Industries Association, Inc. 292 Madison Avenue New York. N. Y. 10017 Telephone: (212) 532-2373 Environmental Health Department September 1, 1972 To: All Members of the LIA Environmental Health Committee Attendees of the LIA Environmental Health Committee Meeting on Occupational Health Exposures held at Trail, B.C.-July 18-19, 1972 Gentlemen: Draft of the document- Industrial Inorganic Lead Poisoning--A Program for Prevention Enclosed is a draft of the recommended program for prevention of Industrial Inorganic Lead Poisoning as developed from the LIA En vironmental Health Committee Meeting on Occupational Lead Exposure held at Trail, B.C. on July 18-19, 1972. We have attempted to incorporate all of the results of the discussions at the Trail meet ing. We would appreciate receiving any comments relating to the draft within two weeks of the above date. Sincerely, 1 > D. R. Lynam Assistant Director Environmental Health ec Enc. L I A0379A N 737.01 INDUSTRIAL INORGANIC LEAD POISONING -- A PROGRAM FOR PREVENTION Recommended Occupational Health Practices for Industries Producing or Using Lead and Its Inorganic Compounds Lead Industries Association, Inc. August, 1972 LI AO 37 9 5 N 737.02 I. Biologic Monitoring The adoption of biologic standards to provide employee protection aul as com pliance standards under the Occupational Safety and Health Act is strongly endorsed. Biological indices of exposure to lead provide much more accurate estimates of lead absorption and possible hazard than do air concentrations. A review of a few of the important publications which describe biochemical tests for estimating the degree of lead absorption and the values likely to be found for varying levels of effects indicate general agreement. (A) R. A. Kehoe:* (1) Lead in Blood. Normal (or usual) - 0. 01 through 0. 04 mg/lOOgm. Abnormal but safe - 0.05 through 0. 07 mg/lOOgm. Potentially dangerous minimum - 0. 08 mg/lOOgm. (2) Lead in Urine Normal - 0. 02 to 0.10 through 0. 15 mg/liter. Dangerous - 0. 20 + mg/liter. (B) International Statement: 2 Categories of Lead Absorption. (The Values Given Below Will Not Necessarily Apply in Cases Where There is a Lowered Haemoglogin Concentration, or Where Chelating Agents, for Example EDTA, Have Been Used) Test A Normal B Acceptable C Excessive D Dangerous Blood lead . . Urinary lead Urinary ccpro- porphyrin Urinary d-aminolaevulinic acid <40 ug. / 100 ml. < 80 ug. /I. <150 ug. /I. <0.6 mg./ 100 ml. 40-80 ug. / 100 ml. 80-150 ug. /l. 150-500 ug./l. 0. 6-2mg. / 100 ml. 80-120 ug. / 100 ml. 150-250 ug. /I. 500-1, 500 ug. /I. >120 ug. / 100 ml. >250 ug. /L > 1,500 ug. /I 2-4mg. / 100 ml. >4 mg. / 100 ml. Blood and urinary lead determinations can be relied on only when carried out in laboratories experienced in the techniques. Even so, errors of + 10% may be ex pected. LIA0 3 7Q(, 2- - Urinary samples of specific gravity less than 1.010 are unreliable and should be rejected; 24-hour samples or repeated spot samples are desirable. A measurement of haemoglogin is important additional evidence; a lowered haemoglobin concentration is commonly found in lead poisoning and may be associated with category C or D. Punctate basophil counts, though still used, are less reliable than the tests shown in the Table, and are not advised. The four arbitrary categories are: (A) Absorption found in the "normal" population when there has been no occupa tional or abnormal exposure. (B) Increased absorption resulting from occupational or abnormal exposure which is occupationally acceptable. At these levels of lead absorption the mild symp toms listed below, which are common to a number of minor complaints, are not attribu table to lead. (C) Increased absorption from excessive occupational or other exposure which maybe associated with mild symptoms or signs (see below), or, rarely, with severe symptoms or signs. Even in the absence of symptoms and signs these levels of ab sorption are unacceptable because of the possibility of toxic episodes and long-term sequelae. (D) Dangerous absorption from occupational or other exposure in which mild, and severe, symptoms and also longterm sequelae are increasingly probable. The following is a list of signatories to the statement: Ronald E. Lane, University of Manchester. Donald Hunter, Guy's Hospital. D. Malcolm, C. E. S. Co. and University of Manchester. M. K. Williams, London School of Hygiene, Univer sity of London. T. G. F. Hudson, Imperial Smelting Co., and University of Bristol. R.C. Browne, University of Newcastle upon Tyne. R. I. McCallum, University of Newcastle. A. R. Thompson, Vauxhall Ltd. A. J. de Kresser, Vauxhall Ltd. R. L. Zielhuis, University of Amsterdam. K. Cramer, Univer sity of Goteberg. P. S. I. Barry, Associated Octel Co. A. Goldberg, Univer sity of Glosgow. T. Beritic, University of Zagreb. E. C. Vigliani, University of Milan. R. Truhaut, University of Paris. R. A. Kehoe, University of Cincinatti, U. S. A.. E. King. University of Manchester. 3 (C) National Academy of Sciences: L I AC 379 7 -3- TABLE 4-11 Levd and Types of Effects of Inorganic Lead Salts as Related to Estimates of Various Levdi of Absocptioa-Reoart and' Remote K> 00 Type of Effects Level 1: No Demonstrable in vivo Effect Level II: Minimal Subdinical Metabolic Effect Level III: Compensatory Biologic Mechanisms Invoked Level IV: Acute Lead Poisoning Mild Severe Level V: Late Effects of Chronic or Recmr- Mmia| Metabolic (accumuUtion and excretion of heme precursors) Changing ALAD4 Functional injury: Hematopoiesis None Kidney (renal tubular function) None * Slight increase in urinary ALA may be present ALA, UCP, FEP ALA. UCP. FEP progressively increased increased 5- to 100 fold Increased if exceaarre exposure recent. but may not be aacreased if excesdve exposure remote None known None known Shortened red-cell lifespan, reticulocy- tosis(t) (revttsible) ? Shortened red-cell life-span and reticulocy tosis with or without anemia (reversible) Amino- Fanconi aciduria, syn- glycosuria drome (i)(re- (revere- veisible) ible) Anemia (i) (revenibic) Chronic nephropathy* (permanent) ft, < i r t ' ra : "4> Ar 1 *' `i1 ` ' + V t/<' Central nervous system Peripheral nerves None None Clinical effects None Index of level of recent or current ab sorption: VOK> Blood lead, eg/100 gof whole blood Urine lead (adults only). *ig/liter <40 - None known None known None known 1 * Nonspecific mild symptoms (may be due in part to coexisting diseases) Mild injury (??? reversibie) Rare Colic, irritability. vomiting Severe injury Severe injury* (perraanent) (permanent) Rare Impaired conduction (wrist, foot drop usually improve dowty, but may be Ataxia, rtnpor, coma. convulsions permanent) Mental deficiency (may be profound). seizure disorder. renal intuffioeacy (gout) (perma nent) 40-60 <80 50-100+ <130 >80 >80 With anemia. intercurrent disease: 50-100+ >130 >130 (May be lea ki revere linear) May be normal Spontaneous excretion may be normal ( See p. 106 for discussion of changing levels of ALAD. *CaEDTA mobilization test in duonic nephropathy is positive; may or may not be positive in permanent central nervous system injury. Ll A0379b 4- - Elkins4 and more recently Williams, et al. ^ have reported on the correlation of airborne concentrations of lead with biochemical levels. Elkins concluded that a urinary lead concentration of 0.20 mg/liter would, on the average, correspond to an air lead concentration of 0.20 mg/m^. Williams reported correlation coefficients for lead in air and various biochemical tests as follows: blood lead (0.90), urinary lead (0.82), urinary coproporphyrins (0. 82), urinary dALA (delta-amino-levulinic acid) 0.68. Williams also reported on the correlations of all possible pairs of biochemical results, which indicated that blood lead and urinary lead were highly correlated (0.90), dALA and blood lead (0. 68), etc. However, the important consideration is not how well various parameters (biochemical tests) correlate with air lead levels or with each other, but what parameters correlate best with the prevention of lead poisoning. All of the problems and inadequacies of air sampling, which are discussed in the next sec tion, are also present in any correlation of biochemical parameters with air levels. An important consideration is whether multiple biochemical tests provide assessment of lead absorption or whether more frequent samples for one specific bio chemical test would provide the most efficient assessment of lead absorption. For example, assume that the results as reported by Williams on the correlations are accurate. Therefore, the use of blood lead and urinary lead results, which are highly correlated (0.90), would most likely not result in an increase in the ability to evaluate lead absorption, and more frequent sampling by one or the other may be more mean ingful. It is believed that lead in blood provides the most reliable index of lead absorp tion and the use of lead in blood determinations is recommended as the primary biologi cal standard. The interpretation of blood lead concentrations should take into consideration several factors not related to lead exposure which may effect the actual value obtained. O The following, from the National Academy of Sciences' "Airborne Lead in Perspective" describes these factors: The following factors must be taken into account in interpreting a given blood lead concentration: Proper collection of whole blood sample and reliability of laboratory performing the analysis, hematocrit value, current or recent ad ministration of chelating agents that temporarily decrease blood lead content, presence of hemolytic anemia, and period since termination of undue exposure. Long-term continuous administration cf a chelating agent, such as D-penicilla mine, suppresses blood lead content to the normal range during the diuresis of lead, and intermittent chelation therapy is associated with fluctuating blood lead content. Marked changes in the mass erf circulating red blood cells may influ ence wholeblood lead content, in that 90% or more of the lead in blood is attached to the red cells. In persons with moderate to severe anemia, clinical evalua tion of the significance of a given blood lead content may be facilitated by correc ting the observed concentration to the approximate value that would be expected if the patient's packed red cell volume (hematocrit) were within the normal range. The relevance of such corrections must, however, be assessed further through LIAT3799 5- - the use of other indices of lead absorption and adverse effects (e. g., response to chelating agents and dALA excretion). Subjects whose high-level exposure has terminated several months to several years previously may still have evi dence of increased body lead burden, as measured by the CaEDTA mobilization test and blood lead concentrations that are minimally to moderately Increased. Recommendations A. The frequency of obtaining blood specimens from employees for lead analysis depend on the severity of exposure. Blood samples must be taken for lead analysis at least quarterly from employees exposed to lead in air levels near the TLV (1. e., 150 pg/W* and greater), but not less often than every six months for any worker exposed to lead. B. Urinary dALA should be determined quarterly as a screening test. A find ing of 2mg/l or greater would indicate the necessity of making a blood lead determina tion. There is some indication that lead workers exhibiting a urinary dALA of 3mg/l have little margin of safety. Such workers should be referred to a physician. C. All blood lead determinations must be corrected for the number of circula ting red cells. Such a correction may be regarded as an additional safety factor for workers who have a deficient number of red cells. Hematocrit or hemoglobin determina tions provide a good basis for the correction providing the blood sample is fresh, and in the case of hematocrit, unclotted. Calculations may be made as follows: Hematocrit: Corrected Blood Lead = observed blood lead hematocrit normal for age observed hematocrit X and sex Hemoglobin: Corrected Blood Lead _ observed blood lead_____ ^ 100% hemoglobin for age, observed hemoglobin (%) sex, and location If the above determinations cannot be carried out on fresh blood samples, then an iron determination may be made and corrected as follows: Corrected Blood Lead - observed blood lead ^ normal blood Fe for age, sex, observed blood Fe and location This latter test will be somewhat more expensive and subject to greater error than either the hematocrit or hemoglobin determinations. D. A corrected blood lead concentration of 80 pg/lOOG should be recognized LI AC 3E0C -6 - as the Biological Limit Value for compliance purposes. E. The following actions should be taken depending on the corrected blood lead concentration found. These actions recognize that there may be a normal analy tical error of j_10 pg/lOOG in blood lead determinations in these ranges. Corrected Blood Pb Level Action 70 pg/lOOG (1) Repeated analysis of Pb in blood. (2) Investigation of employees work habits to deter mine cause of excessive absorption. 80 pg/lOOG (3) Reduction of employee exposure. (4) Medical review. 100 |^/100G (5) Immediate reduction of exposure by "administra tive means until corrected blood lead concentra-* v~ tion is reduced to below 70 pg/lOOG or until phy sician authorizes a higher exposure. F. Because it has been shown that blood lead determinations are subject to gross errors, these determinations should be performed only by experienced labora tories with proven ability. II. Airborne Levels The American National Standards Institute (ANSI) Standard 2.23.11 - 1969, "Standard for Acceptable Concentrations of Lead and Its Organic Compounds, " recom mends an acceptable time-weighted average concentration for lead of 200 pg/m3. The Threshold Limit Value (TLV) for lead, which the American Conference of Governmental Industrial Hygienists (ACGTH) has adopted, is 200pg/m3. However, lead was placed on the intended change list in 1971. If after two years on the intended change list, no evidence comes to light that questions its appropriateness, a value of 150 pg/nr* will be adopted. The reduction in the TLV by the ACGIH has resulted primarily from the work of Williams, et al. 3 The Documentation for the TLV for Lead states: In an extremely thorough study of atmospheric lead exposures and biochemical criteria, Williams et al. found amoung 39 battery workers in Eng land high correlation coefficients between air concentrations and blood lead (r = 0. 9); urinary lead (r = 0. 82); urinary coproporphyrins (r = 0. 82) and urinaiy dALA (r = 0. 68). Lower correlations were found for punctate (stippled) baso philic count (r = 0. 45) and percent hemoglobin (r = 0. 09). Furthermore, they observed that in every case the upper 95% confidence limit considerably ex- LIAC^POl -7 - yfr- ceeded the safe limits, when the air limit is 0.2 mg/m**, but approximates it when the air limit is 0.15 mg/m**. In view of these more recent data using improved biochemical indica tors of response to lead exposure, although originating in Great Britain, but clearly showing that the TLV of 0.2 mg/m** has little or no safety factor for some workers, a TLV of 0.15 mg/m** as lead is recommended as a standard for exposure to inorganic lead dusts and fume. The appropriateness of reducing the TLV for lead on the above basis is ques tioned. The blood lead concentration predicted from air lead concentrations of 150 ^g/m** and 200 ^g/m** were calculated from a regression equation utilizing 39 pairs of air lead and blood lead values. Also the 95% confidence for blood lead at these two air lead con centrations were calculated from these values. The blood lead concentration predicted from the regression equation describing the regression of blood lead on air lead for an air lead of 200 pg/m** was 70 pg/lOOml with 95% confidence limits (expressed for single determinations) of 48 and 92 ^g/lOOml. The blood lead concentration predicted for an air lead of 150 pg/m** was 60 ^/100ml with 95% confidence limits of 38 and 82 pg/lOOml. The basis for the suggested reduction in the TLV from 200 Kg/m** to 150 pg/m** is that the upper 95% confidence limits for blood lead and other biochemical parameters at an air lead of 150 pg/m** do not exceed the "safe limits" for the biochemical tests while the upper 95% confidence limits at an air lead of 200 pg/m** do exceed the "safe limits'*. The data do not justify a reduction for a number of reasons: (1) Confidence limits are dependent on the degree of scatter of the data points so that a large amount of scatter results in a wide confidence band. (2) Confidence limits are dependent on the number of samples taken. An ex periment involving a small number of samples will provide a wider confidence band than an experiment which includes a large number of samples. (3) Confidence limits vary (increase) with magnitude from the mean value (of x). The narrowest confidence band is at the mean value of air lead which appears from the plot of the data to be much less than 0. 20 pg/m^. Therefore, the confidence limits at 0.20 pg/m** are much wider than at the mean air lead value which was approximately O 0.10 to 0.12 iJg/m . In the article, the values in Table 5 listed as means are actually predicted values, not mean values. (4) The confidence limits are for a single determination rather than for the regression line. The confidence band is much wider for a single determination than for the regression line. (5) The results are heavily influenced by plastic department employees where the lead in air concentrations were 9 and 12 pg/m . If this clump of low points is LiAC3P 0 2 -8- omitted it is doubtful that the regression of blood lead on air lead is significant. Further, examination of the data points shows that there were no cases in which the blood lead was higher than 80 pg/m? when the air lead was less than 200 ng/m**. It is apparent, then, that these data do not justify a reduction in the TLV. If anything, they support the 200 pg/m^ figure. 2 An air level of 200 pg/m is adequate to protect the health of the worker if air is the only source of unusual exposure to lead. However, an air lead level should be used only to determine whether biological sampling is required and not as a compliance standard. There are many weaknesses in relying strictly on an air value as a fixed re quirement such as: (A) A standard for lead in air alone does not take into consideration the poten tial exposure from ingestion. Variation in personal hygiene habits of employees may lead to large variations in lead absorption which cannot be detected by air sampling. In a controlled human exposure experiment Kehoe found that exposure to lead in air at a concentration of 150 pg/m^ (8 hrs/dav, 5 days/week for 22 months) produced a blood-lead concentration considerably less than predicted by Williams et al. During this ex posure period the mean stable blood lead concentration was 42 pg/lOOG with a single peak mean concentration (during the 17th month) of 56 pg/m^. It is possible that this subject did not exhibit a higher blood lead level because ingestion, common in plant en vironments, was not a factor in the controlled laboratory inhalation chamber. (B) Air samples do not represent the amount of lead actually absorbed into the body because of differences in particle sizes and solubilities. Air samples currently used by OSHA for compliance purposes do not take into account the significant effect of particle size on lung deposition nor do they take into consideration the effect of chemical composition and solubility of lead on the absorption of lead from either the lung or the alimentary tract. (C) Air samples represent only a small sample or an aliquot of the total volume of air inhaled by an individual. There are many difficulties in obtaining a sample which represents an individual's time-weighted average exposure and a sample of 3 to 4 hours is not indicative of an individual's overall exposure. There are wide fluctuations in airborne concentrations of lead in the workplace and a sample of short duration will most likely not be representative of an individual's exposure. Roach has held that fluctuations in airborne concentrations of a pollutant on a time scale of less than 1/10 of the biological half-life of that pollutant are unimportant for practical purposes. 8 Short sampling periods measure fluctuations In airborne concentrations, which may be on the high or low side of the actual exposure, but these high and low fluctuations are unimportant for compounds like lead, which has a long biological half-life. Roach, using a biological half-life of six months for lead, recommended a sampling timeof ten work shifts. v. (D) Short term air sampling with low flow rates, as is the case with personaltype air samplers, is subject to rather large errors. Contamination of a small sample \_1 -9- is much more serious than in a large one since that contamination will be multiplied several times to arrive at the final concentration figure. Further, the position of the sampling head of the personal-type air sampler is critical. Chatterjee, et al. found a 22% difference in the lead in air concentration measured simultaneously 5 inches apart vertically on chests of exposed lead workers. 9 In the particular case cited, the mean concentration found in the upper position was 181 pg/rn while the mean concen tration found at the lower position was 225 pg/m3. If this test were being used as the basis for a citation it is obvious that, depending on the position of the air sampler, the plant environment would both be in compliance and in violation of a standard of 200 pg/m3. For the above reasons it is obvious that air samples and particularly air samples obtained through the use of personal-type air samplers, should not be used for compliance purposes. Because of the ingestion factor a lead-in-air standard can fail to protect a worker. On the contrary, biological monitoring provides an index of exposure to all sources of lead. Recommendations A. Air sampling should be used only for these purposes: (a) to indicate the necessity to institute biological monitoring. (b) to indicate areas in which engineering controls should be instituted and to evaluate the effectiveness of these procedures. B. If, despite the inadequacies of air standards for compliance purposes, an air lead standard is adopted, no citation should be issued for exceeding this standard unless the blood lead concentrations exceed the biological limit value (80 pg/lOOG). C. Attention should be directed to the use of size selective sampling for lead in air and to the various compounds of lead so as to provide a more reasonable esti mate of the "absorbable" portion of airborne lead. HI. Recommended Industrial Practice A. Controls (1) Feasible Engineering Controls Engineering controls may include isolation, enclosure, local exhaust ventila tion and shall be the primary means of reducing lead exposure. (2) Specifications Under Which Personal Protection Devices Should Be Required The use of personal protection equipment shall be required in the following circumstances: (a) During the time period necessary to install the engineering controls and to institute the work practices required to reduce exposure when necessary. (b) In work situations in which engineering control methods and work practices are either technically not feasible or feasible to an extent insufficient to reduce LI A C3 6 3A - 10 - the exposure to or below required limits. Respirators used shall be approved by the US Bureau of Mines for "dusts and fumes not significantly more toxic than lead "and used in accordance with the procedures outlined in the Respira tory Protective Devices Manual. (3) Work Practices and Procedures (a) Adequate washing facilities must be provided. (b) Double lockers, so as to separate contaminated from uncontaminated cloth ing, must be provided. (c) Lunchroom facilities must be separate from lead processing areas. (d) Shower facilities must be separate from lead processing areas. (e) Dust suppression compounds or water should be used in dusty areas to minimize airborne dust. (f) Dry sweeping should be avoided by the use of vacuum sweeping when feasible. (g) Clothing control is an integral part of exposure control. 1. Steps must be taken to prevent contamination of workers' homes and families by contaminated clothing. 2. Protective over clothing should be provided for use in jobs where clothing contamination by lead is a significant factor. (h) Smoking, eating and drinking in lead processing plants shall be prohibited except in specified "clean" areas. Smoking materials and foodstuffs shall not be brought into lead processing areas. (i) Employees must practice careful personal hygiene. Careful washing of hands and fingernails prior to eating and showering after the work shift are important components of exposure reduction. B. Medical Aspects (1) Medical Examinations (a) Preemployment - All prospective employees who will be exposed to lead shall have a preemployment medical examination. Special tests shall include a blood lead determination and a urinary dALA determination. (b) Periodic - All employees exposed to lead shall have a medical review at least annually. The content of the medical review shall be at the discretion of the physician but should include a review of blood lead and urinary dALA re cords. medical records and. If Indicated, a personal interview. Detailed phy sical examinations should be undertaken if warranted by the medical review. (c) Special - See part I., Biological Monitoring Recommendation V. LlA03f05 11 - (2) Treatment Medical treatment for lead poisoning should not be necessary if the practices outlined in this document are followed. However, the following recommnedations re garding treatment are made: (a) No treatment should be undertaken unless specific symptoms of lead poi soning are present. (b) Intravenous EDTA is the recommended means of therapy when treatment is indicated. (c) The prophylactic use of oral EDTA and milk, sometimes called "preventive medicine" is strongly discouraged on the grounds that both are ineffective and that prolonged use of EDTA may have adverse consequences. C. Recordkeeping Accurate medical and biological monitoring records of employees exposed to lead shall be maintained by the employer. These records should be retained by the employer for at least 20 years or for the working life of the employee. D. Warning Labels Caution labels shall be affixed to raw materials and products containing lead compounds when the material changes ownership and when inhalation or ingestion of fumes, dust or powders could result in dangerous absorption during use. The labels should state: CAUTION CONTAINS LEAD AVOID INGESTING AND BREATHING FUMES AND DUST FOR PROLONGED PERIODS If a description of symptoms resulting from overexposure to lead is required, it is recommended that the following wording be used: Effect of Overexposure: Prolonged excessive absorption of inorganic lead by ingestion or inhalation of dust and fume may cause abdominal pain or what is sometimes referred to as "lead colic, " metallic taste in mouth, loss of weight, pains in the muscles, muscular weakness, constipation and nausea. The sim ilarity of these symptoms with those of other illnesses require that excessive absorption of lead be verified by medical examination and analyses of biological specimens. Skin or Eye Contact: For inorganic lead compounds, absorption through the skin is of no practical importance. Emergency First Aid Procedures: Unimportant for lead. LI AC 3606 - 12 - REFERENCES 1 Kehoe, R. A.: Occupational lead poisoning 2 - Chemical signs of the absorption of lead. J. Occup. Med. 14:5, 390-396, 1972. 2 Lane, R. E. etal: Diagnosis of inorganic lead poisoning: A statement. Brit. Med. J., pg. 501, Nov. 23, 1968. 3 National Academy of Sciences: Airborne Lead in Perspective. National Academy of Sciences, Washington, D.C., 1972. 4 Elkins, H.B.: Chemistry of Industrial Toxicology. Wiley and Sons, New York, 1969. 5 Williams, M. K., King, E. , and Walford, J.: An investigation of lead absorption in an electric accumulator factory with the use of personal samples. Brit. J. Indust. Med. 26:202-216, 1969. 6 American Conference of Governmental Industrial Hygienists: Lead (TLV Document ation for LEAD - final revision included with letter from H. E. Stokinger to J. F. Cole, August 13, 1972.) 7 Kehoe, R. A.: The metabolism of lead in man in health and disease - The Harben Lectures, I960, J. Roy. Inst. Pub. Health Hyg., pgs. 1-81, 1961. 8 Roach, S. A.: A more rational basis for air sampling program. Amer. Indust. Hyg. Assoc. J., pgs. 1-12, Jan. -Feb., 1966. 9 Chatterjee, B. B., et al: The location of personal sampler filter heads. Amer. Indust. Hyg. J., pgs. 643-645, Nov.-Dec., 1969. 10 American Industrial Hygiene Association, American Conference of Governmental Industrial Hygienists: Respiratory Protective Devices Manual, AIHA, ACGIH, 1963. LI/S03807