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FILE NAME Threshold Limit Values TLV DATE 1988 DOC TLV003 DOCUMENT DESCRIPTION Corporate Influence on Threshold Limit Values American Journal of Industrial Medicine 531-559 1988 Corporate Influence on Threshold Limit Values Barry I. Castleman SCD and Grace E. Ziem MD DrPH Investigations into the historical development of specific Threshold Limit Values TLVs for many substances have revealed serious shortcomings in the process followed by the American Conference of Governmental Industrial Hygienists Unpublished corporate communications were important in developing TLVs for 104 substances for 15 of these the TLV documentation was based solely on such information Efforts to obtain written copies of this unpublished material were mostly unsuccessful Case studies on the TLV Committee's handling of lead and seven carcinogens illustrate various aspects of corporate influence and interaction with the committee Corporate representatives listed officially as consultants since 1970 were given primary responsibility for developing TLVs on proprietary chemicals of the companies that employed them Dow DuPont It is concluded that an ongoing international effort is needed to develop scientifically based guidelines to replace the TLVs in a climate of openness and without manipulation by vested interests Key words unpublished corporate communications TLV committee carcinogen conflict of interest industrial experience OSHA standards INTRODUCTION The Threshold Limit Values TLVs published by the American Conference of Government Industrial Hygienists ACGIH have been widely adopted as workplace exposure standards The ACGIH values have been very influential over the past 40 years in Belgium West Germany Austria Italy The Netherlands Portugal Denmark Sweden Finland Norway Spain Switzerland the United Kingdom and Japan Toyama 1985 Vigliani et al 1977 In the developing countries as well the TLVs have been relied upon by governmental occupational health authorities Noweir 1986 However it has nonetheless been widely recognized that the TLVs for chemical substances are in most cases poorly supported by scientific evidence This is clear from even a casual review of the Documentation of the Threshold Limit Values and Biological Exposure Limits 5th Edition 1986 West Germany adopted the ACGIH values in 1955 and has been influenced by the ACGIH in setting exposure limits ever since But the German authorities upon review of the documentary adequacy of their MAKS concluded that less than 10 percent of the limits were based on sufficient The authors are independent consultants in occupational and environmental health Address reprint requests to Barry Castleman 1722 Linden Ave. Baltimore MD 21217 Accepted for publication September 14 1987 '1988 Alan R. Liss Inc. 532 Castleman and Ziem animal tests and field experience Henschler 1984 This finding based initially on a review of 150 substances has been more recently corroborated by review of 300 more substances on the German MAK list Henschler 1985 ACGIH's TLVs have been directly criticized by both industry and labor representatives for scientific inadequacy Henderson 1975 Samuels 1981 This report examines the historic role of industry in the development of the TLVs Role of Industry in TLV Process The American Conference of Governmental Industrial Hygienists established a Committee on Threshold Limits which issued annual reports starting in 1946. ACGIH was and continues to be a voluntary organization with no formal ties to the U.S. government despite its name Its members were initially federal state and local officials and within a few years academics and known industry consultants were also included From the beginning the TLVs were acknowledged to involve a balancing of health considerations and cost to industry Report 1948 Industry data were invited In order to understand this interaction it is necessary to appreciate the dependence of the TLV committee on information from industry especially prior to the 1970s In the United States government toxicologists and industrial hygienists of this era had very limited access to knowledge of effect relationships in industry There was no federal regulation of general industry workplace hazards until 1971 and state and local agencies were thinly staffed and minimally funded These agencies had little if any regulatory power and lacked laboratory and other technical resources so vital to the surveillance of hazards in industry At U.S. universities faculty occupational health professionals depended upon industry goodwill for research funding consulting and field experience and jobs for their students Government funding for occupational health research was virtually nonexistent Dr. John Knox medical officer for Turner and Newall an asbestos multinational corporation headquartered in Britain recorded his impressions in notes of a 1960 visit to his company's U.S. subsidiary Knox 1960 The legislative framework under which industries operate in the U.S.A. makes it difficult for me here to follow the lines of thought which prompt action over there in the matter of standards of industrial practice In many industries the employers seem so far in front of legislation as to have created a special code of practice for themselves It was well recognized that to the extent that data existed on exposures to toxic agents and ill health in industry they had been mostly developed by industry Industrial concerns in the U.S. were in no way compelled to share what they knew Under the chairmanship of toxicologist Herbert Stokinger the TLV committee first tried the approach of prodding industry by issuing a Notice of Intent to change some TLVs in 1964. A number of companies responded supplying data leading to 9 of 23 new additions that year Notice of Intent 1965 Stokinger wrote to the Manufacturing Chemists Association now Chemical Manufacturers Association Stokinger 1964 Corporate Influence on TLVs 533 This was particularly encouraging in view of the fact that the committee has never had a significant amount of voluntary contributions from indus- trial sources as long as I can recall 13 years despite annual exhortations welcoming such information By 1966 a committee of the Industrial Medical Association now American Occupational Medical Association expressed concern over the growing impact of the TLVs on industry At the same time it was acknowledged that industry had data on file and the means to develop more data that could contribute constructively to the establishment of realistic TLVs Golz et al 1966 Over the years Stokinger had had a number of meetings with industry groups at the Mellon Industrial Hygiene Foundation to discuss proposed changes in TLVs The TLV committee's 1968 Notice of Intent even invited industry data via the Industrial Hygiene Foundation Repository of Anonymous Occupational Health Data Committee 1968 However little if anything of value was ever obtained in this way Stokinger 1986-87 From the time the idea was first suggested the Industrial Medical Association had apprehensively observed that documents in a data repository might be subject to subpoena in damage suits Minutes 1967 In 1969 Stokinger described the lack of appropriate industrial hygiene data as the greatest problem facing the TLV Committee Describing the American chemical industry's contribution of data on new substances to the TLV committee'as pathetic Stokinger who was employed at the U.S. Public Health Service addressed industry's responsibility directly Stokinger 1969 The TLVS are industry's values . . industry has the sole responsibility to develop data on its own products government is not in a position to develop the facilities to handle the problem in total nor should it when reliable toxicologic consultants are now available Original emphasis Regarding chronic animal exposure data Stokinger commented Stokinger 1969 The data are in short supply because industries either do not develop term studies or if they do more often than not do not see fit to release the data in the open literature Various reasons are given for this legal protection of their products lack of staff time to put data in publishable form Whatever the reason the data are not forthcoming The following year 1970 the Occupational Safety and Health Act was passed by the U.S. Congress and virtually the entire 1968 list of TLVS became enforceable federal standards In future OSHA standards development the TLV committee could well have been expected to have a considerable influence In the chemical industry the Dow Chemical Company had developed some rapport with the TLV committee in the 1960s Dow had provided unpublished data on at least 5-10 products commented on the committee's documentation for specific TLVs and discussed work published by Dow toxicologists and others around the world In 1970 this relationship deepened with the enlistment of Dow toxicologist V.K. Rowe as a liaison member of the TLV committee and his worker Theodore 534 Castleman and Ziem TABLE I. TLV Documentation Assignments Substance trade name 2,4,5 T ethylene glycol vinyl chloride methyl bromide propylene glycol methyl ether Dowanol PM methyl chloride 1,2 dibromoethane ethylene dibromide 1,2 dichloroethane chlorostyrene methylene chloride 1,2,4 trichlorobenzene vinylidine chloride dicyclopentadiene clopidol Coyden tricyclohexyltin hydroxide Plictran chlorpyrifos Dursban picloram Tordon dimetholate 3,5 tolamide Zoalene dimethyl sulfate dibromopropyl phosphate Styrene chloroethyl ether 1,2,3 trichlorobenzene chloroform dipropylene glycol methyl ether Dowanol DPM ethanolamine trichloromethyl pyridine Serve crufomate Ruelene chlorodifluoromethane chromates methomyl Lannate perfluoroalkanes cyclopentane xylene a -diamine bromacil Hyvar X diuron Karmex dioxane calcium hydroxide cyclopentadiene dibromochloropropane cyanamide azodrin dicrotophos Bidrin phthalodinitrile isophthalonitrile dioxin Person assigned Rowe Torkelson Torkelson Torkelson Morgan Morgan and Torkelson Torkelson Morgan Torkelson Morgan Zavon Torkelson Year first assigned 1970 1971 1972 1972 1973 1973 1974 1974 1975 1975 continued Corporate Influence on TLVs 535 TABLE I. TLV Documentation Assignments Continued Substance trade name Person assigned phosgene toluene diamine hexamethyl phosphoramide formamide dimethyl sulfoxide dichloromonofluoromethane methylene bis chloroaniline MOCA tetramethylthiourea tetramethylthiourea hexachlorobutadiene amino 1,2,4 triazole Amitrol deodorized kerosene toluene concentrate acrylonitrile Morgan Morgan Zavon Torkelson Year first assigned 1975 1976 1976 1976 Torkelson as alternate industry liaison member Dupont industrial hygienist James Morgan joined the committee in 1972 and together with Torkelson he played an active role in the work of the committee for the rest of the 1970s and into the present decade Torkelson and Morgan became two of the four members of the new subcommittee on carcinogenic substances established in 1972 Minutes 1972 The minutes of the TLV committee in 1972-1976 show that primary responsibility for reviewing documentation in developing TLVs was borne by corporate representatives for major products of their own companies and new products about which little or nothing had been published Torkelson was well situated to know about the toxicity of Dow Chemical's halogenated hydrocarbons and pesticides Tordon Ruelene Dursban and Plictran By the same token Morgan would appear to have been well placed to know about DuPont's carcinogenic products dimethyl sulfate lead chromate Moca hexamethyl phosphoramide chlorofluorocarbons Freon products and pesticides Lannate Hyvar X and Karmex Dow and DuPont also had substantial economic reasons for wanting to influence the TLV committee on these and other products But these economic considerations were adverse to the free and full flow of information from the companies The 1970s would see government regulators charged with the protection of workers the environment and consumers very busy with some of the chemicals in Table I. The demonstration of vinyl chloride's carcinogenicity cast a shadow over a large number of halogenated hydrocarbons A reference point for regulators in every case would be the currently accepted limit for maximum human exposure namely workplace exposure And since most of OSHA's limits were from the aging 1968 list of TLVS regulators looked to the current TLV lists and designations of carcinogenicity by the TLV committee for guidance The chemical companies and trade associations contesting standards at OSHA the Environmental Protection Agency and the Consumer Product Safety Commission included Dow and DuPont High TLVs tended to reduce the costs of regulation to the chemical industry Moreover there were liability considerations in addition to regulatory ones Manufacturers of products involved in damage suits before juries readily resort to the claim that the use of the product was not expected to exceed the TLV and was thus 536 Castleman and Ziem considered safe The TLV defense offers manufacturers the plausible deniability that any harm sustained was foreseeable Where a manufacturer has evidence that the exposure involved was in fact below the TLV this may even be used to support a denial that the product caused health impairment Duplicity of corporate representatives clearly angered longtime Massachusetts occupational health official and TLV committee member Hervey Elkins who writing a letter of retirement to Chairman Stokinger in 1975 Elkins 1975 stated In looking over the new documentation I was taken aback by that for ethylene glycol the limit of 100 ppm was found intolerable by sedentary volunteers ina few minutes or seconds I believe that industry represen- tative recommended this figure In spite of his knowledge he seems to come up with some recommendations for TLVs that are way too high in my judgment The same can be said for most of the other industry representatives we have had In many cases they recommend a TLV much above the action levels used in their own plants By the time of Elkins complaint Dow Chemical had long been assigning internal corporate exposure limits for toxic substances Other firms including Rohm and Haas had also decided to adopt this practice Corporate workplace exposure limits have served as a managerial tool both for substances with assigned TLVs and others for which TLVs had not been adopted Faustenbach and Langner 1986 Regulatory and liability concerns appear to have deterred corporate management from publishing these lists and supporting rationales their obvious practical value and potential importance in preventing occupational disease MATERIALS AND METHODS The 1986 Documentation of the Threshold Limit Values and Biological Exposure Indices was reviewed for all chemical substances Where reference appeared in the text to unpublished communications and internal corporate reports etc. a determination was made as to whether such information had been important in setting the TLV or classifying the substance's carcinogenic status This was a matter of judge- ment based on the full text for each chemical substance listed Due to the wide variation in type and quantity of information used as a basis for the various TLVS rigid criteria could not be used it is presumed that different experts conducting such a review would come up with slightly different lists of TLVS for which unpublished corporate communications would be judged important The important communications can be generally described as animal data data from tests on human volunteer subjects and industrial experience Communications coming from corporations and trade associations are in many cases so identified in the Documentation However in many other cases only the names of individuals are published in the Documentation The institutional affiliations of these people at the times they sent information to the Committee on Threshold Limits have been investigated in various ways The sources checked included contemporary publications by the same people past directories of professional associations American Industrial Hygiene Association American Occupational Medical Corporate Influence on TLVs 537 Association ACGIH and retired members of the TLV committee contacted by telephone for their recollections Attempts were made in several ways to obtain copies of unpublished material cited in the Documentation The New Jersey Department of Health requested copies of specific references on 67 substances in 1985 from ACGIH and companies named in the Documentation for the purpose of developing chemical fact sheets later as a pattern of irretrievable unpublished corporate statements emerged the information was reanalyzed for this paper An examination was also made of the historic TLV Committee files at the National Institute for Occupational Safety and Health NIOSH in Cincinnati The surviving files kept there by United States government employees who had served on the TLV Committee covering years from the late 1950s through the 1970s contained a small number of letters and reports cited in the Documentation Though ACGIH has copies of TLV committee minutes for the last 10 years the Board of Directors would not grant access to them Kelly 1986-87 RESULTS For a total of 89 substances the 1986 TLV Documentation placed important reliance on unpublished corporate communications Table II Another 15 substances were assigned TLVS solely on the basis of unpublished corporate studies and reports Table III This investigation was able to locate written copies of far less than half of the above unpublished corporate material from the NIOSH files ACGIH and the corporations Of the 89 substances in the first group above corporate affiliation of the referenced source person was not published for 25. For the 15 TLVs based solely on unpublished corporate communications the companies providing information were all identified in the Documentation There was thus a total of 104 substances for which important or total reliance was placed on unpublished corporate communications This accounts for over one sixth of the number of less than 600 chemical substances listed in the 1986 Docu- mentation Of the 17 corporations asked for documentation they had provided to the TLV committee nine sent old documentation or commented on their work to the New Jersey Department of Health The unpublished documentation in most cases was unobtainable from the companies Table IV and the historic TLV committee records in NIOSH files There were no files available from ACGIH itself nor did former longtime committee members Stokinger Elkins have personal files on the chemicals Stokinger admits that some of the information was never conveyed in writing but came over the telephone Stokinger 1986-87 In any event most of these important unpublished corporate communications are now unobtainable in written form for independent scientific examination Industrial Experience The TLV committee's reliance upon unpublished corporate communications included reports of industrial experience on dozens of chemical substances The content of these reports rendered in the Documentation often appears in just the space of a sentence or two Table V The scientific community is left unable to determine whether there was more information originally conveyed and where there was no 538 Castleman and Ziem TABLE II TLVs for Which Unpublished Corporate Data was Important Substance acrylic acid acrylonitrile asphalt fumes benomyl benzene butyl acrylate butyl alcohol" butyl glycidyl ether caprolactam carbon disulfide catechol chlorinated camphene 60 chlorinated diphenyl oxide chloracetaldehyde chloracetyl chloride chlorodifluoromethane chlorostyrene chlorotoluene chlorpyrifos copper cyclopentadiene cyhexatin dibutyl phthalate dichlorodifluoromethane dichloroethylene dichlorofluoromethane 2,2 dichloropropionic acid dichlorotetrafluoroethane dicrotophos dicylopentadienyl iron diethyl phthalate diglycidyl ether dimethyl acetamide dimethylamine dimethylformamide dimethyl sulfate diphenylamine octyl phthalate endrin ethion ethylene dichloride" ethylenimine ethyl morpholine fenamiphos fonofos hydroquinone isonctyl alcohol isopharone isopropoxyethanol lead chromate manganese and compounds manganese tetroxide methacrylic acid methomyl methoxyphenol methyl butyl ketone methyl chloride methyl cyanoacrylate methylene cyclohexyl methylene bisphenyl isocyanate methylene chloride 4,4 methylene dianiline methyl isocyanate metribuzin monocrotophos paraquat piperazine dihydrochloride propionic acid quinone resorcinol rosin core solder pyrolysis products silicon tetrahydride silver and compounds sulfuryl fluoride aulprofos tetracthy lead tetramethyl leadfi tetrahydrofuranfi thioglycolic acid 1,2,4 trichlorobenzene trichlorofluoromethane 1,1,2 trichloro 1,2,2 trifluoroethane trimethyl phosphite tungsten compounds vinylcyclohexene dioxide xylidine zinc stearate Includes substances assigned carcinogenicity status Does not include papers presented at scientific conferences Corporate affiliation of correspondent not published in Documentation of TLVs Corporate Influence on TLYs 539 TABLE III Documentation of TLYs Solely by Unpublished Corporate Communications Substance butyl lactate Animal data acute Animal data subacute or chronic butylphenol x clopidol dinitolmide divinylbenzene X ethyl amyl x ketone hydroxypropyl x acrylate isophorone x diisocyanate isopropyl X aniline methyl acetylene- propadiene mixture nitrapyrin phenylphosphine tetrasodium pyrophosphate triphenyl amine x xylene ox diamine x 2 teratol x 2 teratol 30 da x 4 wks x 4 mos x 93 days x 90 day Human data x ---- ---- x x Source year Philips En- doven 1969 British Petroleum 1972 Dow 1977 Dow 1973 Dow 1977 Shell 1958 1965 Dow 1977 VeraChemie 1977 Dow 1964 Dow DuPonti 1970 1977 Kodak 1973 Dupont 1973 Sherwin- Williams 1978 Includes an industrial hygiene bulletin by Shell Chemical Corporation claiming no systemic effects in workers exposed to concentrations above the TLV recommended by the company way exists to look up the original source and resolve questions about the basis of statements published in the Documentation including methodology utilized and whether the statement was based on any study or mercly an impression Because of the weight given to these reports and the great value of studies industry could perform on the workers exposed to these agents special attention to these communications is warranted The information provided by companies and published by ACGIH in the Documentation raises obvious and fundamental questions What exactly did Dow's routine medical examinations and any analysis performed on them show to establish that no evidence of exposure occurred at the reported concentrations of methyl chloride What tests were conducted and what analysis was carried out by Dow What was the scientific content and methodology of the unpublished negative mortality studies on acrylonitrile benzene dimethyl sulfate and ethylenimine What were 540 Castleman and Ziem TABLE IV Requests of Data from Corporations Corporation Number of Chemicals Results Dow Hooker Hercules Crown Zellerbach FMC Rohm and Haas Cyanamid DuPont 33 No information received 2 The company provided a report for one chlorotoluene of the two requested chemicals Study methods and results were described animal study For one chemical chlorinated camphene Hercules stated they had sold the operation to Nor and stated any toxicologic information must now come from Nor Hercules did not say they no longer had the information Nor stated they no longer produced it and that much of the correspondence and reports had been discarded For the other chemical Rosin core solder pyrolysis products the study was provided with detailed methods and results However inflammation and hyperemia in multiple organs for both controls and exposed animals causes one to wonder about inadvertent exposure of controls The Documentation states industrial experience has been good over the years Crown Zellerbach's correspondence describes 3 yr experience manufacturing the chemical catechol with only few mild toxic reactions CZ notes no physical abnormalities . . . noted by observation not stated whether all workers had physical exams or in multichannel blood tests type frequency other methods unspecified While catechol is an irritant there is no mention of the use of symptom questionnaires or lung function tests in this 1975 communication 12 No information received carbofuran Significant material sent describing study methods and results for animal studies on both chemicals Study report noted Squamous metaplasia of nasal mucosa thought secondary to irritation ethyl acrylate This effect not voted in Documentation The company provided information on one phorate of the two chemicals requested This was an inhalation study level unspecified for 8 hr involving 12 animals observed for 7 days after exposure The report merely says there was no evidence that they were affected in any way There is no mention of whether pathologic studies or biologic monitoring were conducted let alone reporting of such findings The criteria for no effects were unspecified Some information not always complete was sent for all 7 chemicals The Documentation states that there were no complaints of illness and no abnormal liver function tests in employees exposed at roughly half the TLV for several years dimethyl formamide The information provided by the company to NJDOH does not appear to be a reference upon which such a statement could have been based the original basis for the statement not be located An epidemiological study of 143 workers exposed to dimethyl sulfate showed that few deaths from respiratory cancer occurred among them while employed by DuPont The work force was not broken down in terms of either time elapsed from onset of exposure or duration of exposure to DMS No follow of employees and retirees was done continued Corporate Influence on TLYS 541 TABLE IV Requests of Data from Corporations Continued Corporation Number of Chemicals Results Western Electric Sherwin Williams Mobil Oil Ethyl C Koppers Eastman Kodak Union Carbide Shell Oil B.F. Goodrich No data were provided to substantiate Zapp's communication 1970 to the ACGIH that methylene bis cyclohexylisocyanate was less toxic on inhalation than TDI Dupont's subacute study on dogs found to have no skin irritation or sensitization effects unlike results . . previously reported tetrahydrofuran was given greater credence than the published positive studies by the TLV committee because of the greater number of animals involved The DuPont study used 4 dogs A day study of phenylphosphine contained adequate discussion of methods and results DuPont's study of mxylene a"diamine found generally mild sensitization in all 10 guinea pigs tested This is mentioned in the Documentation as evidence of sensitization without noting that all animals were affected The Documentation refers to a subacute study by DuPont in 6 rats as one which caused no fatalities dicyclopentadienyl iron The Documentation omits data showing that in addition to irritability and weight loss all 6 rats showed testicular atrophy It is unclear whether these effects were ever communicated to the TLV committee report was obtained from the company but not in the TLV files Western Electric did not provide the correspondence for isophorone but it was obtained from the TLV committee files and consisted of five sentences noting two symptom complaints urinanalysis and kidney function checks No methods discription was given nor was the number of employees noted nor whether questionnaires were used or if they waited for employees to complain No medical surveillance data was provided even in summary form No response to request for information xylene a diamine Epidemiologic study conducted on employees for eye effects only with exposure levels evaluated study methods described Unclear whether study was ever published trimethyl phosphite No response to request seeking information tetraethyl lead The Documentation states that a survey of 180 men employed in work involving resorcinol revealed that none complained of irritation or discomfort at exposure levels of 10 ppm The company provided no information about any study but merely sent a safety data sheet on the chemical No discussion of methods was provided in Koppers letter to the TLV committee which was located in the committee's files Letters on animal studies were located for 2 chemicals o chlorotoluene triphenylamine Observations on workers could not be located for the other 2 dibutyl phthalate di- octyl phthalate No response to request for information Shell no longer makes the 3 chemicals and states that correspondence concerning them is no longer available The Documentation states observations in the rubber industry have revealed no adverse effects from many years of inhalation of zinc stearate dust The company had discarded the correspondence but stated that there was no organized study of workers exposed to zinc stearate 542 Castleman and Ziem TABLE V. Unpublished Industrial Experience Cited in TLV Documentation acrylonitrile asphalt fumes benzene butyl alcohol butyl lactate caprolactam carbofuran carbon disulfide catechol chlorinated camphene toxaphene chlorodifluoromethane chlorotoluene dibutylphthalate diethylphthalate octylphthalate octylphthalate diglycidyl ether dimethylformamide dimethylsulfdimaethytlsuelfate diphenylamine endrin ethylene dichloride ethylenimine hydroquinone Monsanto 1981 epidemiology negative on carcinogenic effects Hammond Humble Oil opinion of industrial hygienists that conditions were satisfactory at 10 mg Ott et al Dow 1975 epidemiology revealed no excess mortality Banks Shell Chemical Company hygienist reports that many years of industrial experience at 100 ppm have resulted in no difficulties Turner British Petroleum 1972 reported that 7 ppm was not found to be objectionable or injurious Ferguson Allied Chemical 1972 reports on 143 workers some of whom were exposed up to 17 years to vapor concentration as high as 5-10 ppm without any evidence of damage to health Tobin FMC Corporation undated given as source Workers exposed to concentrations approaching 0.1 mg per day have not shown any effects Calhoun American Viscose 1968 reports no cases of carbon disulfide poisoning since 1942 when exposures averaged below 2.5 ppm Crown Zellerbach 1975 referenced as reporting industrial experience has been good under adequately controlled conditions Hercules Inc. 1969 reports that review of records of 137 employees some exposed up to eighteen years failed to reveal any adverse effects that could be associated with toxaphene Reinhardt DuPont undated reports that cardiac arrythmias are not considered a possibility under currently recommended industrial hygiene practices Hopton Hooker Chemical 1962 reports that no cases or dermatitis or poisoning from this compound had been encountered Raleigh Kodak undated reports workers exposed to 1 p6pm of mixed phthalates had no phthainlthaeit r belos od and had no peripheral polyneuritis White Shell Chemical Company 1962 recommends a ceiling limit of 0.5 ppm on the basis of a effect level in animal studies and industrial experience TWA 0.1 ppm DuPont undated reports no complaints of illness and no abnormal liver function tests at about one half the TLV DuPont 1972 epidemiology covering a period of 15 years and an update in 1976 show no excess of lung cancer in exposed workers Dernehl Union Carbide 1967 cites industrial experience in recommending a satisfactory operating level On this basis the same value was selected as the TLV 10 mg Jager Shell no medical effects seen with 233 workers comparing them before and after 10 years exposure to endrin and related pesticides body weight blood pressure WBCs and SREs Fassett Kodak 1964 Experience in one plant indicated that concentrations in the range of 25 to 50 ppm were safe for prolonged exposure Dow report of BASF 1973 epidemiological study revealed no evidence of carcinogenicity in 144 workers some of whom had 40 years experience Fassett Kodak undated reports that clinical and environmental studies of workers confirm that no systemic effects arise at the TLV continued Corporate Influence on TLVs 543 TABLE V. Unpublished Industrial Experience Cited in TLV Documentation Continued manganese and compounds methyl butyl ketone methyl chloride methylene bisphenyl isocyanate 4,4 methylene dianiline monocrotophos paraquat propionic acid resorcinol tetraethyl lead tetramethyl lead trimethyl phosphite tungsten compounds vinyl cyclohexene dioxide zinc stearate Whitman Bethlehem Steel 1976 reports no cases of manganism in workers exposed for years to 1 to 5 mg of manganese dioxide dust Raleigh Tennessee Eastman Co. 1976 reports no history of muscular weakness parathesia loss of coordination or clinical evidence of neuropathy in 37 employees engaged for 3 years in the manufacture of methyl butyl ketone Dow undated reports that a routine periodic medical program did not identify evidence of overexposure to methyl chloride at concentrations averaging 30 ppm Imperial Chemical Industries 1962 reports no cases of skin irritation during early industrial experience handling this compound Dow 1977 reports no morbidity findings for exposures ranging from 0.03 to 0.4 ppm over 26 years Shell Chemical undated reports no decrease in field workers cholinesterase concentrations following exposure Gage Imperial Chemical Industries 1968 is cited as reporting that no serious injury or illness resulted from eight years agricultural use of paraquat Dow 1977 reports that at reported exposure levels no irritation was noted Medical reports include mild eye redness and one case of mild cough and asthmatic response Koppers Company 1974 reports that none of 180 men exposed to 10 ppm complained of irritation or discomfort Linch DuPont 1968 reports that exposures averaging about 20 over the TLVs produce average urinary lead concentrations not significantly elevated above a high normal no values above 0.15 mg Ethyl Corporation undated reports that 3/4 of the TLV for tetraethy lead is a rough guideline for an allowable TLV Mobil Chemical Co. 1980 reports no ocular changes among 179 workers with exposures reported Plant exposure data could be interpreted to indicate that concentrations of 1 ppm certainly and very likely 2 to 4 ppm are without significant adverse effect TLV raised from 0.5 to 2 ppm in 1982 Dernehl Union Carbide 1966 reports that long industrial experience has indicated workers exposed to solely tingsten and its insoluble compounds do not develop pneumoconiosis Dernehl Union Carbide 1973 referenced as source In the U.S. industrial experience over the past 10 to 20 years has been good B.F. Goodrich Rubber Co. undated referenced as source Observations in the rubber industry have revealed no adverse effects from many years inhalation of zinc stearate dust no concentrations given the parameters and data underlying Hercules unpublished communication to the effect that a review of employee medical records failed to reveal any adverse affects that could be associated with toxaphene Similar questions arise over the nature and quality of industrial experience relied upon by the TLV Committee for 32 other chemical substances see Table V An even larger number of TLV substances were assigned exposure limits after significant reliance on unpublished corporate communications about animal experiments 544 Castleman and Ziem In this survey a TLV Documentation reference was counted as published even if it was from a manufacturer's safety data sheet or an unsupported statement published in a text by a corporate health professional The brevity age and obscurity of such documentation raises serious questions of reliability despite the fact of such references being published Manufactureres safety data sheets while briefly noting chemicals health ef fects or lack of effects are not generally useful as primary sources for detailing the scientific basis of health effects statements Safety data sheets are not written to convey the important data underlying statements like no health problems have been attributed to the use of this agent in industry or it is an irritant but not a sensitizer Yet TLVs are still based on such statements by manufacturers on safety data sheets issued in the 1950s e.g. ethyl ketone methylamine nitromethane The use of corporate safety data sheets of even recent vintage is inappropriate for documenting TLVs Some reports of no adverse industrial experience in the 1986 Documentation originally appeared in classical texts but were unsubstantiated by data and are now very old In the case of morpholine the text refers to the 1963 edition of Patty's toxicology text as a basis for saying that no chronic effects have been reported The primary source cited was a 1948 review on morpholine issued by the American Petroleum Institute Patty's text was in large part written by industry professionals and some of the statements appearing in the text though unexplained there went on to be cited as the basis for TLVs Patty himself reported on ethyl acetate concentrations he had measured during a period of several months during which time no adverse symptoms or illnesses were observed Patty who was an industrial hygienist at General Motors did not explain whether the observations made were those of physicians himself or other medically untrained management officials supervisors foremen personnel managers TLVs for Carcinogens The case studies of six carcinogenic materials will be considered next in order to examine in some detail the work of the TLV committee in this important area These summaries illustrate a number of ways in which the committee was informed and influenced by industrial parties Some of the materials on the first lists of MACs as they were called in the early years were known or suspected of being human carcinogens These agents included asbestos 1946 arsenic 1947 and chromates 1950 Threshold limits for these materials appear not to have been based on their carcinogenic effects however Arsenic In the case of arsenic and its compounds the 1947 value was 100 mThe following year Hill and Faning produced strong epidemiological evidence of a lung and skin cancer hazard in a factory making sodium arsenite sheep Hill and Faning 1948 Median room air concentrations of arsenic measured in the chemical plant were 71 254 373 and 696 gm Average urinary arsenic concentrations of the workers were in the range of 0.09 to 0.24 liter Perry et al 1948 For reasons not explained at the time the threshold limit for arsenic was raised in 1948 from 100 to 500 m In the first published documentation of the TLVS in 1962 the subsequent experience of the American Smelting and Refining Company Corporate Influence on TLVs 545 was cited as supporting 500 mThe source of this information was the company medical director Pinto 1961 Documentation 1962 In acknowledging Pinto's confidential report Stokinger replied It was surprising to see what a clean bill of health you were able to produce in view of the many implications of arsenic and lung cancer Stokinger 1961 Pinto's work was published in 1963 showing that both employees exposed to arsenic and employees with arsenic exposure had a greater incidence of lung cancer than males in the state of Washington The exposed group had urinary arsenic levels of 0.82 liter and the unexposed smelter employees had urinary arsenic burdens averaging 0.13 liter Pinto and Bennett 1963 Pinto later conceded that the latter group in this controversial report was in fact exposed to low arsenic levels but denied a suggestion published by the Occupational Safety and Health Administration OSHA that there had been reporting of lung cancer cases in the 1963 study Pinto and Nelson 1976 The National Institute for Occupational Safety and Health evaluated Pinto's 1963 report as showing an increase in lung cancer mortality contrary to the conclusions of the authors Inorganic 1975 A 1974 mortality study on the workers at the same Asarco copper smelter confirmed their lung cancer hazard Milham and Strong 1974 In 1975 OSHA responded to mounting reports of lung cancer in arsenicexposed workers by proposing a reduction in the workplace standard for arsenic from 500 to 4 m The original standards was 500 because the 1968 TLV values for most substances were adopted en masse as enforceable standards with the passage of the Occupational Safety and Health Act of 1970 The Threshold Limits Committee of ACGIH followed by adopting two TLVs for arsenic trioxide in 1977 50 mat smelters and 250 min smelting environments This aroused bitter resentment at NIOSH and OSHA where the actions of the TLV Committee were seen as aiding the industry challenges to the government standard The government researchers and regulators were especially piqued at Dr. Stokinger who was then Chairman of the TLV Committee while drawing a government salary at NIOSH Referring to the actions of the TLV Committee on arsenic OSHA said The detailed basis for arriving at these levels is not clear on the record Occupational Exposure 1978 OSHA's final standard for inorganic arsenic issued in 1978 was 10 mof air averaged over an hr period Occupational Exposure 1978 The TLV Committee first listed arsenic trioxide production as a human carcinogen in Appendix A of the TLV booklet in 1975. In 1980 arsenic trioxide production was reclassified as a suspect human carcinogen and numerical TLVs for this process and for insoluble arsenic compounds were completely eliminated Asbestos The TLV adopted by ACGIH in 1946 to 1970 for asbestos was based upon the tentative recommendations of a Public Health Service study published in 1938 Dreessen et al 1938 The P.H.S. survey showed that workers exposed to more than 5 million particles per cubic foot MPPCF of total dust in the air of asbestos plants clearly developed asbestosis But the P.H.S. survey also found early to moderate asbestosis in workers with less than 50 MPPCF of cumulative exposure The P.H.S. findings and those of an earlier medical survey by Pennsylvania 546 Castleman and Ziem labor authorities strongly indicated that workers eventually would develop asbestosis from exposures under 5 MPPCF Fulton et al 1935 Lung cancer among asbestos workers was first reported in the 1930s and by 1939 German state insurance carriers were compensating lung cancer in combination with even slight asbestosis as an occupational disease Baader 1939 Pathologists around the world continued to contribute data and comments on the coincidence of those two diseases through the 1940s In 1949 the British government published powerful confirmatory statistical evidence in 235 deaths in which asbestosis had played a role fully 31 13.2 percent also involved cancer of the lung or pleura Annual Report 1949 The old 5 MPPCF threshold was never regarded as safe by leading asbestos industry consultants Drs Leroy Gardner Arthur Vorwald and Anthony Lanza A similar lack of faith in this TLV as an index of safety was expressed publicly and privately in the 1940s 1950s and 1960s by executives and health professionals of the leading asbestos companies in the United States and the United Kingdom as well as health authorities in these and other countries Castleman 1986 In 1964 the old TLV for asbestos was repeatedly criticized by government and industry speakers at a widely publicized conference on asbestos held by the New York Academy of Sciences Ann N.Y. 1965 By this time it was evident that nearly half of all asbestos insulation workers whose average exposure was of the same order of magnitude as the TLV were dying from occupational cancer and asbestosis The ACGIH Threshold Limits Committee had included asbestos industry con- sultants from its earliest years Industrial hygienist Manfred Bowditch who was on the Committee in 1946 and 1947 was then also trying to fulfill contracts the Saranac Laboratory had made with the asbestos industry Castleman 1986 Bowditch's deceased predecessor at Saranac Leroy Gardner had performed studies in confidence for asbestos manufacturers and the manufacturers wanted to publish some of the results not the animal studies showing asbestos causing lung cancer however Dr. Arthur Vorwald the next director of the Saranac Laboratory accommodated asbestos industry sponsors with his publication of Gardner's cancer related research in 1951 Castleman 1986 Vorwald et al 1951 and Vorwald 1948 That year he joined the Threshold Limits Committee on which he served until 1956 During these years Vorwald evaluated at least 30 cases of suspected and proven asbestosis and cancer many of which were the subject of compensation claims for companies in the United States and Canada He also conducted a confidential animal inhalation study which appears to have confirmed asbestos carcinogenicity in the early 1950s however this was never discussed in Vorwald's publications Castleman 1986 Vorwald 1952 Dr. Paul Gross at the Industrial Hygiene Foundation since 1971 Industrial Health Foundation became a member of the Threshold Limits Committee from 1964 198G3ross consulting work on asbestos included case pathology reviews for Manville in the 1950s and confidential animal research on brake drum dust for Manville in the 1960s Castleman 1986 As a member of a U.S. Public Health Service committee in 1969 Gross secretly provided draft copies of a report to three asbestos companies Dr. Robert deTreville President of the Industrial Hygiene Foundation inviting comment explained W will attempt to see that needed corrections are introduced by Dr. Paul Gross a member of the Committee deTreville 1969 In 1976 Gross resigned from a committee of the National Academy Corporate Influence on TLVs 547 of Sciences amid charges of improperly sharing information with a company he consulted for - the issue was health effects of asbestos in drinking water Wade 1976 Upon joining the Threshold Limits Committee Gross became chairman of the subcommittee on insoluble respirable dusts Minutes 1965 ACGIH's Threshold Limits Committee briefly considered having a separate more stringent TLV for the crocidolite variety of asbestos A 1968 Notice of Intent was circulated so that connected individuals principally but others also may have an opportunity to help shape the deliberations of the Committee prior to its published recommendation of tentative changes in the 1967 Threshold Limits List Commenters were asked to write either to Dr. Stokinger at the Public Health Service or to the Repository of Anonymous Occupational Health Data in care of Dr. Treville at the Industrial Hygiene Foundation Committee 1968 Revisions under consideration . . proposed for 1968 List of TLVs included the following for asbestos A limit of 5 MPPCF based on impinger samples counted by field technics sic is satisfactory to control exposures to most forms of asbestos Crocidolite however has been shown to produce in addition to the asbestotic inflammation also mesothelioma Since no safe limit can be established for this form of asbestos at this time until more definite data are obtained it is recommended that workers exposed to crocidolite be equipped with supplied helmets This idea of stringently controlling exposure to crocidolite asbestos dust was dropped before the publication of the 1968 book of TLVs Over the next few years the ACGIH published notices of intent to lower the TLV for all varieties of asbestos and change the method of analysis to phase contrast microscopy but the formally adopted value remained 5 MPPCF through 1970 Finally in 1974 ACGIH listed an adopted TLV of 5 cc for asbestos using phase contrast microscopy two yr after OSHA had established a standard at that level through formal rulemaking In 1980 ACGIH lowered its TLV for chrysotile asbestos the most abundant variety to 2 cc and set lower limits for crocidolite and amosite By this time government standards for chrysotile had been in effect at the 2 cc level for 4 yr in the United States and 11 yr in Britain The TLV for crocidolite asbestos only 0.2 cc is equal to the current 1986 OSHA asbestos standard for all types of asbestos No notice of intended change for asbestos has been published by ACGIH since 1980 It is noteworthy that despite the comparatively slow process governments must follow in developing standards under their laws and despite the reluctance of conservative governments to regulate industry in the 1980s ACGIH has lagged behind both OSHA and the British government in lowering limits for workplace exposure to the leading recognized cause of occupational cancer Vinyl Chloride Upon the recommendation of Dr. Robert Scala at Esso the TLV committee proposed lowering the limit for vinyl chloride gas to 50 ppm from 500 ppm McFarland 1965 This was largely based on animal tests published by Torkelson in 1961 where effects were noted at 100 ppm and a TLV of 50 ppm was recommended 548 Castleman and Ziem Torkelson et al 1961 Following the circulation of the committee's 1966 Notice of Intent Chairman Stokinger was invited to the Industrial Hygiene Foundation IHF in early 1966 to discuss the proposed changes in the TLV list There he met with 50 representatives of companies with membership in IHF in Pittsburgh Stokinger was told that industrial experience suggests that 50 ppm may be too low Report 1966 Consequently the proposed change of vinyl chloride's TLV was put off on suggestion of Dr. Torkelson that the Committee await further accumulating experience Stokinger 1966 The committee lowered the TLV to 200 ppm in 1971 based on unpublished Dow findings of liver dysfunction in workers exposed to 300 ppm vinyl chloride combined with 5 ppm vinylidine chloride Documentation 1971 Dow representatives maintain that the company reduced its internal employee exposure limit to 50 ppm in 1961 but in practice this limit was knowingly exceeded as Dow first reported the above data in 1968 Documentation 1971 Paustenbach and Langner 1986 The first U.S. workplace standard for vinyl chloride was 500 ppm the 1968 TLV It was revealed in 1974 that vinyl chloride workers had died from angiosarcoma of the liver and that similar turnors had been produced in experimental animals at 50 and 250 ppm OSHA issued a proposed standard for vinyl chloride specifying that exposures be below detectability using instrumentation sensitive to 1 ppm But official U.S. government statements that the safety of the gas had not been demonstrated at any level were publicly denounced by Stokinger as irrational and unfortunate in a letter to the National Cancer Institute In an interview with the New York Times Stokinger went on to say that there was ample and increasing evidence that there are threshold levels for carcinogens below which there is little risk Official 1974 OSHA issued a 1 ppm standard for vinyl chloride later in 1974 and the U.S. industry not only met that goal but promptly resumed its growth PVC 1976 In the meantime the TLV committee had taken on members from industry including Torkelson of Dow Chemical a major manufacturer of vinyl chloride Torkelson had primary responsibility for TLVs for vinyl chloride and a number of other volume halogenated hydrocarbons starting in 1971 Minutes and Agenda 1970-1976 It was not until 1977 that the committee issued a new TLV for vinyl chloride 5 ppm which still stands The TLV for vinyl chloride was thus set at one tenth the concentration carcinogenic to animals for a proven human carcinogen This conflicts with the current TLV committee claim that safety factors of 100 to 1,000 have traditionally been used to determine TLVs for carcinogens Identification 1986 Dimethyl Sulfate The TLV for this vapor used as a war gas in World War I was originally set at 1 ppm in 1946. German reports in the late 1960s showed that DMS was carcinogenic in rats and probably also in workers and the Germans lowered their MAK for this vapor to 0.01 ppm in 1971 as animal studies revealed serious lung damage at 0.5 ppm Henschler 1975 The TLV committee had published its first listing of carcinogens as an appendix to the TLV booklet in 1971 consisting of only nine entries mostly dye intermediates In early 1972 the committee's annual Notice of Intended Changes informed readers that this list was being expanded with separate groupings of human and experimen- Corporate Influence on TLVs 549 tal carcinogens The listing of DMS in the former category prompted inquiries from five chemical companies Stokinger replied to them sending copies of underlined articles and saying sufficient number of human cancers of the lung have been observed to make it highly probable that dimethyl sulfate is a carcinogen for man Stokinger 1972 A few months later DuPont provided Stokinger with a copy of a letter from a doctor at BASF a German manufacturer of dimethyl sulfate The writer pointed out that the German MAK list denoted dimethyl sulfate as an experimental animal carcinogen but not a human carcinogen Morgan J.F. 1972 The next month DuPont sent Stokinger an epidemiological report which formed the basis of our conclusion that dimethyl sulfate is not known to have produced human cancers among potentially exposed persons Stokinger was asked to limit distribution of the study to persons having a need to see it Morgan J.F. 1972 The DuPont study examined employee lung and larnyx cancer rates at three plants where DMS had been handled However usable data identifying the employees exposed to DMS before 1961 were available for only one plant During 19321970 97 wage roll workers and 46 salaried employees had worked at some time in the DMS area There were two deaths each from lung and larynx cancer among the DMS workers between 1956-1970 with retirees and employees clearly not fol- lowed up When OSHA issued an Emergency Temporary Standard for carcinogens in 1973 Stokinger argued for a distinction to be made between known human carcino- gens and others on the OSHA list Writing as Chairman of the TLV committee Stokinger relied on the unpublished DuPont report to assert that no excess of respiratory cancers had occurred among DMS workers Manufacturing exposure control was completely effective without the requirement for pressurized suits . . Stokinger cited other unpublished reports from DuPont and Dow to argue that two of these companies products covered by the OSHA standard MOCA ethylenimine also were not human carcinogens Stokinger 1973 The TLV committee member with responsibility for DMS in the period 1972 1976 was James Morgan of DuPont sole U.S. manufacturer of DMS Minutes and Agenda 1970-1976 The committee assigned a TLV of 0.1 ppm in 1977 ten times the limit previously accepted in Germany Benzene The TLV for benzene was adjusted downward from 100 ppm in 1946 50 ppm in 1947 35 ppm in 1948 to 25 ppm in 1957. The TLV committee adopted 25 ppm as a ceiling exposure limit in 1963. An industry consensus standard of 10 ppm with daily min peaks of 50 ppm was issued in 1969 by the American National Standards Institute Consequently 10 ppm was the first benzene limit adopted by OSHA NIOSH 1974 British industry and government writers urged Stokinger to abandon the 25 ppm ceiling in favor of a 10 ppm average value as early as 1966 King 1970 Stokinger 1966 The TLV committee first proposed this change in 1968 but deferred its adoption until 1977 Hueper had assessed benzene as almost certainly a proven cause of leukemia in 1942 Hueper 1942 The German MAK commission had listed benzene in 1971 among nine human carcinogens for which zero concentration values are given 550 Castleman and Ziem because the objectionable concentration is not yet known Morgan L. 1972 Benzene was classified by the TLV committee as a suspected human carcinogen in 1975 The 1986 Documentation contains no references less old than 1977 and relies on one report whose findings were reversed in 1977. That year OSHA issued an emergency temporary standard and proposed a permanent standard of 1 ppm for benzene An adverse Supreme Court ruling in 1980 based on the record of the benzene standard issued in 1978 prompted OSHA to conduct quantitative cancer risk assessment and again propose a 1 ppm limit in 1985 The 1986 Documentation refers to unpublished work by Ott in 1975 as showing no excess mortality among benzene workers However Ott concluded that this same cohort of Dow Chemical employees demonstrated a significant excess of myelogenous leukemia prompting Dow to announce a new corporate ceiling limit of 10 ppm in 1977 Benzene 1977 Ott et al 1978 Dow epidemiologists have now seen 4 deaths from myelogenous leukemia in this work force versus 0.9 expected a fifth worker with leukemia was listed as dying with pneumonia Bond et al 1986 Infante at OSHA notes that average benzene exposure of these workers was 5.5 ppm Infante 1987 Similarly the 1986 Documentation makes no mention of related chromosomal abnormalities among Dow workers exposed to benzene concentrations below 10 ppm Infante and White 1983 These findings were withheld by Dow during the OSHA benzene hearings in 1977 prompting the researcher involved to quit in 1978 in order to release his results Because of the company's delay in releasing these findings the researcher denounced Dow as unethical and immoral Picciano 1979 Scott 1978 The TLV committee which adopted a companion short exposure limit of 25 ppm to go with the 10 ppm average for benzene in 1980 is discarding the short- term limit in 1987. Exposure at even 10 ppm for eight min is illegal under the OSHA benzene standard published September 11 1987. The standard requires that exposures average no more than 1 ppm with min peaks no more than 5 ppm The committee's position in 1987 thus resembles that of the American Petroleum Institute in its 1978 court challenge to the overturned benzene standard The past decade of benzene toxicology research has not been incorporated into the TLV Documentation The research and policy at Dow Chemical whose senior toxicologist was an active member of the TLV committee if known to the committee have been disregarded without mention Acrylonitrile Following the reports of positive animal studies by inhalation and ingestion as well as positive epidemiological findings OSHA regulated acrylonitrile as a carcinogen in 1978. Acrylonitrile was also classed by ACGIH as a human carcinogen in 1978. Following the publication of an inconclusive epidemiological study in Britain and the receipt of epidemiological communications to the TLV committee from Monsanto Company in 1981 acrylonitrile was reclassified under industrial substances suspect of carcinogenic potential for man The Monsanto conclusions were quoted by the TLV committee no published study is yet available for scrutiny by the scientific community Corporate Influence on TLVs 551 Ethylenimine When OSHA proposed to regulate this compound as a carcinogen in 1973 Dow's Dr. D.J. Kilian provided the basis for the TLV committee observation that despite this chemical's toxic and carcinogenic effects in animal studies industrial experience has been good The entire basis for this was the following second report of a telephone conversation between two major manufacturers Kilian 1973 Today I talked by telephone to Dr. Theiss medical Director of Badische Anilin and Fabrik in Germany the only other major manufacturing site of ethylenimine and he stated that they had just finished an epidemiological study of 144 of their EI workmen The exposure time on some was 40 years and they found no evidence that EI was a human carcinogen Dr. Kilian also wrote that he and Dr. Theiss planned to combine their companies experience in a medical publication in the near future It does not appear that any study was subsequently published Ethylenimine was removed from the TLV booklet's appendix list of experimental carcinogens after 1974 presumably upon the recommendation of the subcommittee on carcinogens which included Torkelson of Dow Chemical sole U.S. producer of the material Carcinogens in General The TLV committee has now stated its intent to formally evaluate chemicals classified as carcinogens by other organizations but not ACGIH Spirtas et al 1986 ACGIH has published a table listing the carcinogenic status of more than 300 substances according to five national and international organizations Identification 1986 The most appropriate comparison is with the list of the German Research Society maximum workplace concentrations MAK Commission The ACGIH classifies 11 materials in the aforementioned table as human carcinogens the MAK Commission's total is 17. The ACGIH classifies 40 other entries as suspected human carcinogens the corresponding MAK commission totals are 42 compounds proven carcinogenic in animal experimentation only and 61 more justifiably suspected of having carcinogenic potential Identification 1986 Maxi- mum 1984 The TLV committee avoided listing animal carcinogens of major industrial importance including trichloroethylene and dioxane These and other unnamed compounds were exempted by the Committee Guidelines for Classification of Experimental Animal Carcinogens published in 1976. The guidelines are unique in that they set maximum carcinogenic dosages above which no practical importance is attributed for positive animal experiments Lead Because of their enormous significance in occupational health and the manner in which their TLVs emerged the story of inorganic and organic lead compounds could hardly be overlooked in this review Inorganic Lead From 1946 through 1956 the TLV for lead and its inorganic compounds was 0.15 mg This followed earlier recommendations of the U.S. Public Health 552 Castleman and Ziem Service and an American Public Health Association committee on lead Later editions Documentation of the industries observed that this limit proved difficult to achieve in many mg Explaining the 1957 decision to raise the lead TLV to 0.20 the first edition of the Documentation said Long industrial experience with the 0.15 mg limit however showed that. . lead absorption as measured by urinalysis were sic not indicative of harmful exposure No reference for this was given The 1966 Documentation went on to describe the blood lead concentration of 80 micrograms per 100 ml as normal and noted that repeated exposures above 0.20 mg could cause higher blood lead burdens indicative of incipient lead poisoning Pressure for lowering the TLV developed in November 1968 when an inter- national commission on occupational health recommended 0.15 mg In preparation for discussions with industry the TLV committee summarized recent developments on lead toxicity and reviewed the Basis of Present TLV Under this last heading were three items all unpublished corporate communications from Bowditch Lead Industries Association Dooley Texaco and Nelson Asarco Review 1970 Neither Stokinger nor Elkins can now recall what information was provided by these individuals over 30 years ago and no primary written documentation has been found in Stokinger's old files at NIOSH On May 1 1970 a meeting was held by TLV committee members Stokinger and Frederick with representatives of the automotive and lead industries state health officials and others Industrial representatives said they used blood lead analyses for health control measures and urged that air sampling be advised only as an engineering guide General Motors hygienist Vincent Castrop acknowledged that his company used 0.15 mg as its guideline Stokinger 1970 The TLV committee then readopted the former value of 0.15 mg which has unchanged since 1973. A short min exposure limit of 0.45 mg remained mwas also adoptedin 1976 later to be discardedin 1986. The current Documenta- tion includes an attack on NIOSH for a standard of 0.10 mg recommending rejects the OSHA standard of 0.05 mg promulgatedin 1978 Organic Lead Compounds When tetraethyl lead was introduced as a gasoline additive in the 1920s lead poisoning was a major product of the industry About 80 of the workers at DuPont's New Jersey production facility were believed to have been lead poisoned and the plant was known to workers as the House of the Butterflies because of the hallucinations afflicting employees there DuPont was accused of suppressing information from the press even in cases where workmen were hospitalized and died from lead poisoning Rosner and Markowitz 1985 Tetraethyl lead TEL and tetramethyl lead TML were given TLVs of 0.075 mg in 1963 and 1967 respectively The main basis for the tetraethyl lead TLV consisted of statements by industry representatives that this limit was observed by Ethyl Corporation without apparent ill effects on the workers Documentation 1966 Publication of the second of these TLVs brought forth a Confidential letter of protest in 1967 from Dr. Robert Kehoe the lead industry's foremost medical expert its consultant and a defender of the tetraethyl lead industry since the 1920s Rosner and Markowitz 1985 Kehoe urged that both TLVs be discarded with the least possible fanfare His Dear Herb letter concluded Kehoe 1967 Corporate Influence on TLVs 553 would not take the risk of subjecting a group of men to working conditions represented by this atmospheric standard for any reason whatever and yet this level is being adopted on a worldwide basis and I have little doubt that it will be applied literally by someone sometime as being authoritative It is not so applied in any part of the industry at present Kehoe invited Stokinger to be his lunch guest at the Queen City Club a private club in Cincinnati catering primarily to businessmen Kehoe 1967 Stokinger accepted and recalls that Kehoe pontificated without supplying any data Stokinger was aware that Kehoe had become a wealthy man over decades as the principal U.S. industry expert on lead poisoning Though Kehoe presumably represented industrial interests in this matter no firms were specifically named Stokinger 1986-87 The most influential members of the TLV committee rejected the idea of dropping the limits for TEL and TML and instead cautiously challenged the responsible industries to produce some response data In its January 1968 Notice of Intent the committee wrote that a downward revision of the TLVs for both lead alkyls was being considered No new proposed limits were given Committee 1968 At least one manufacturer of these compounds found that operations involving each of these chemicals exceeded even the current TLV of 0.075 mg But organic lead air concentrations averaging as high as 0.121 m for TEL and 0.179 mg for TML reportedly corresponded to average urinary lead concentrations not significantly above a high normal - meaning less than 0.15 mg The source of this encouraging news was A.L. Linch whose employer never noted in the Docu- mentation was DuPont The date of this communication to the TLV committee chairman is recorded as April 1 1968 The TLV committee held its semiannual meeting over the next two days April 2-3 1968 and decided to raise the TLVS to 0.10 mg for TEL and 0.15 mg for TML Stokinger 1968 These limits were formally adopted in 1970 and remain the same to this day No written communication from Linch to Stokinger has been found and given the rapid sequence of events here the cited report from Linch appears to have been a telephone call Stokinger 1986-87 It has been proposed recently that OSHA try to adopt current TLVs to update the exposure limits for hundreds of substances While this would yield stricter limits for many substances whose OSHA limits are still the 1968 TLVs the opposite would result for the lead alkyls This is especially worrisome in view of the fact that the OSHA standard for organic lead compounds is now more permissive than that for the inorganic lead compounds which are less toxic this anomaly will be worsened if OSHA adopts the current TLVs for the lead alkyls Blas of TLV Committee Membership Dr. Hector Blejer resigning from the committee in 1980 after 10 years as a member protested what he called an increasingly stronger industry bias . . particularly among almost all the Committee consultants and among the members who consult privately for private industry Blejer went on to blame this industry bias and repeated unnecessary disagreements with NIOSH and OSHA for having made the TLV committee and ACGIH appear NIOSH OSHA and labor Blejer 1980 554 Castleman and Ziem To its discredit the committee has long turned a blind eye to conflicts of interest both overt and subtle Health and safety professionals tend to view policy issues from a spectrum of opinions from those who would resolve the benefit of doubt in assuring the fullest worker protection to those who are more sensitive to corporate financial priorities where health and safety is in practice regarded as an expenditure to be controlled as much as possible It is no accident that professionals with the latter point of view are more likely to consult for or be employed by corporations and those closer to the former viewpoint are more likely to be independent of corporate funding perhaps working in government or for labor unions public interest groups etc. The TLV committee never acknowledged this reality or attempted to achieve a balance between corporate- and affiliated health professionals Only occasional token efforts were made to get a union industrial hygienist on the TLV committee There the union person could expect to be marginalized at least as badly as was Dr. Blejer a NIOSH expert on lead arsenic cadmium and asbestos by the sheer force of numbers and adversaries with vastly superior technical resources The TLV committee never offered unions and other strong advocates of worker protection a chance to participate on a fully equal basis The occasional token offers for participation in effect only gave unions the choice of participating in an unequally balanced arena and depleting their resources with little chance of being heard - or of no participation at all CONCLUSIONS AND RECOMMENDATIONS While earlier reviews of the TLVs themselves have been critical the process of TLV development has not been critically examined in the past The unavailiabity of unpublished corporate documentation precludes scientific scrutiny of the primary basis for nearly one sixth of the documented TLVs At the same time the TLV committee's uncritical acceptance of industry assertions based on scant unpublished data raises yet greater concern The documentation of TLVs for their own companies products by industry members of the TLV committee constitutes a major conflict of interest This happened on a large scale in the 1970s with the Dow Chemical representative primarily responsible for TLV development for major Dow products vinyl chloride vinylidine chloride chloroform methyl chloride ethylene dichloride ethylene dibromide trichlorobenzene dioxane ethanolamine dipropylene oxide methyl ether styrene ethylene dibromochloropropane Tordon Ruelene Dursban and Plictran and the DuPont representative doing the same for major DuPont products dimethyl sulfate MOCA lead chromate formamide dichloromonofluoromethane Lannate Karmex and Hyvar X Chemical Week 1975 Minutes and Agenda 1970 1976 The listing of dominant corporate TLV committee members as consultants and the issuance of statements to the effect that they did not officially vote on the TLVs were deceptive Lee 1987 The concealment of industry influence on the TLVS is a serious matter quite apart from the exercisofe that influence itself Aside from the participation of employed health professionals the TLV committee has extended full membership to time industry consultants as early as 1951 Dr. Arthur Vorwald of the Saranac Laboratory To this day TLV Corporate Influence on TLVs 555 committee members can and do earn a substantial fraction of their incomes as industrial consultants while publishing only their university affiliations in the TLV booklet ACGIH has no policy either restricting TLV committee membership in such cases or requiring public disclosure of consulting work for financially interested parties Similarly there is no policy restricting the chemicals assigned to TLV committee members because of conflicts of interest through employment consulting and research grants Kelly 1986-87 The TLV committee's lack of adequate resources is evident from its finances As part of the ACGIH a volunteer organization the committee now has an annual budget of 30,000 most of which goes for travel and lodging expenses to conduct meetings Kelly 1986-87 The members of the committee must rely on whatever technical resources and support services are available to them as individuals computer searches libraries research assistants clerical assistants and borne by them and their employers for their unpaid committee work e.g. distance telephone calls Over the years this has meant that committee members have had to work on TLVs on their own time and their own expense with their own resources unassisted As a result documentation on many chemicals seems to have been prepared with minimal review of the literature The TLVs have nonetheless been widely represented and accepted as scientifically based limits that would protect virtually all workers from health impairment over a lifetime of exposure on the job Lee 1987 The TLVs are assumed by many to be first world first class guidelines for worker protection The consequences of such misplaced confidence in the TLVs are profound and global The credibility of the ACGIH limits as scientifically independently and verifiably determined persists as an obstacle to a better standard of worker protection Industrial hygienists need clear instruction regarding the limited nature of the TLVs Hygienists too often assume or convey to workers that exposure below the TLV can be regarded as safe They need training which would enable them to assess more adequately the scientific grounds upon which the TLVs are based They also need increased training in eliciting and evaluating worker complaints of illness during field inspections This approach should replace the technician approach of simply cranking out numbers with monitoring comparing them to a table and then assuming all is well if exposures measured are less than the TLVs OSHA is now considering adopting current TLVs to replace its exposure limits from the 1968 TLV list Z table While for some chemicals this may represent an improvement it is clear that we cannot assume that the current TLVs are scientific or adequate Since more rigorous and thorough documentation has been done for the chemicals for which NIOSH recommends specific maximum exposure levels OSHA should adopt NIOSH levels where these are stricter than those of the ACGIH Finally since many chemicals have not been assessed by NIOSH and others need updating OSHA should consider the adoption of TLVS or NIOSH values as a stopgap measure not a substitute for ongoing rigorous assessment of chemical exposure values With the more recent emergence of better trained and equipped groups issuing workplace exposure limits and supporting documentation in North America Europe and elsewhere it now seems appropriate for an international effort to be mounted to gradually replace the TLVS This can be done under the auspices of an internationally respected organization with the participation of leading experts from around the world with sufficient financing Corporations with their own internal lists of occu- 556 Castleman and Ziem pational exposure limits can contribute to this process by publishing these lists and supporting data without further delay Openness of the process is essential as is the exclusion of financially interested parties from having leverage in the deliberations Policies regarding disclosure of income and conflicts of interest must be accepted by the participants so that the highest level of credibility maintained Policies regarding making any use of and maintaining public repositories for unpublished documentation will also be needed Public access to minutes of meetings should be assured and provided for Yet even a panel of the best technical experts would not overcome all obstacles inherent to the process of setting worker exposure limits There are implicit assumptions in any process of establishing some acceptable level of chemical insult to which humans may be exposed Many scientists reject safe exposure levels for carcinogens and certain reproductive hazards The concept of safe exposure limits for other chemicals is less often questioned however even though scientists are unable in practice to determine safe exposures They can only determine levels below which their limited measurement tools are unable to detect effects in a finite and often very limited number of workers Thus the very concept of safe exposures to any chemical is inherently unscientific Indeed the term threshold limit embodies this unproven and probably unprovable concept that there is some known level of exposure which does not adversely affect the organism Discarding the term threshold limit is a necessary first step in correcting this false ideology of the past Rather the numerical values for exposure limits selected as acceptable by one social group scientists for another social group workers is very much a political as well as a scientific process The Norwegian Administrative Norms for example explicitly acknowledge that the chemical exposure limits reflect economic as well as medical and technical considerations The Norwegian authorities consider that while writing the documentation for chemicals is ideally a scientific process the setting of numerical limits is a political process It is time that we all openly acknowledge the political nature of decisions by unexposed scientists and regulators regarding maximum levels of chemicals to which other humans can knowingly be exposed The decision process therefore must not only be freed from undue corporate influence it must also include substantial participation by representatives of exposed persons REFERENCES Ann NY Acad Sci 1 7615965 Annual Report of the Chief Inspector of Factories for the Year 1947 1949 London HM Stationery Ofc PP 79 81 Baader EW 1939 Asbestosis Deut Med Woch 407 408 Benzene Ceiling Level Lowered to 10 PPM July 14 1977 Dow Today No. 41 Dow Chemical Pub Relations Dept. Blejer HP June 5 1980 Letter to Col. VL Carter Chairman TLV committee Bond GG McLaren EA Baldwin CL Cook RR 1986 An update of mortality among chemical workers exposed to benzene Br J Ind Med 685 691 Castleman BI 1986 Asbestos Medical and Legal Aspects 2nd Ed Clifton N.J Prentice Law & Business Chemical Week 1976 Buyers Guide Issue Oct. 29 1975 New York McGraw Corporate Influence on TLVs 557 Committee on Threshold Limits of the American Conference of Governmental Industrial Hygienists 1968 Notice of Intent NIOSH files 3 pp Criteria for a Recommended Standard Occupational Exposure to Benzene 1974 NIOSH pp 68 69 de Treville R Sept. 10 1969 To IHF Fibrous Dust Study Sponsors Memorandum Documentation of Threshold Limit Values 1962 A.C.G.I.H. Cincinnati pp 10 11 Documentation of Threshold Limit values 2d Ed 1966 A.C.G.1.H. Cincinnati pp 184 185 Documentation of the Threshold Limit Values 3rd Ed 1971 A.C.G.L.H. Cincinnati pp 277 Dreessen WC Dallavalle JM Edwards TI Miller JW Sayer RR Easom HF Trice MF 1938 A Study of Asbestosis in the Asbestos Textile Industry Pub Health Bull No 241. Washington Elkins HB May 24 1975 Letter to H. Stokinger NIOSH files Fulton WB et al 1935 Asbestosis Pennsylvania Dept. of Labor and Ind Harrisburg Golz HH Culver BD Hardy HL Miller LH Raleigh RL Roush G Tusing TW 1966 Report of an investigation of threshold limit values and their usage J Occup Med 280 283 Henderson R 1975 U.S. experience with occupational safety and health legislation industry view Ann Occup Hyg 335 338 Henschler D July 31 1975 Senate Commission of the German Research Society on the Testing of Toxic Workplace materials Letter to H. Stokinger and enclosed Toxicological Occupational Medicine Documentation on dimethyl sulfate NIOSH files Henschler D 1984 Exposure limits history philosophy future developments Ann Occup Hyg 79 92 Henschler D 1985 Personal communication to G. Ziem Hill RH Faning EL 1948 Studies in the incidence of cancer in a factory handling inorganic compounds of arsenic Br J Ind Med 1 6 Hueper WC 1942 Occupational Tumors and Allied Diseases Springfield Illinois Charles Thomas pp 594 599 Identification and Classification of Carcinogens 1986 Appendix to Documentation of Threshold Limit Values and Biological Exposure Indexes 5th Ed Cincinnati A.C.G.I.H. pp 86 to 86 Infante PF 1987 Personal communication to B. Castleman Infante PF White MC 1983 Benzene epidemiologic observations of leukemia by cell type and adverse health effects associated with level exposure Environ Health Perspectives 75 82 Inorganic Arsenic Proposed Exposure Standard Jan. 21 1975 Occupational Safety and Health Admin Fed Register 3392 3404 Kehoe R. Oct. 11 1967 Kettering Laboratory Univ of Cincinnati Letter to H. Stokinger NIOSH files Kelly WD 1986-87 Executive Secretary A.C.G.I.H. Letter of Jan. 21 1987 and other personal communications to B. Castleman Kilian DJ Oct. 17 1973 Dow Chemical Co. Letter to H. Stokinger NIOSH files King B Aug. 11 1970 National Occup Hyg Services Ltd. U.K. Letter to H. Stokinger NIOSH files Knox JF 1960 Report of visit by Dr. J.F. Knox to Keasbey & Mattison Company August 4 15960 Turner and Newall document 2 pp Lee JS 1987 A letter from the chair of ACGIH Appl Ind Hyg P7 MacFarland HN October 25 1965 Hazelton Laboratories Inc. Letter to H. Stokinger NIOSH files Maximum Concentrations at the Workplace and Biological Tolerance Values for Working Materials 1984 Deutsche Forschungsgemeinschaft Verlag Chemie Weinheim Milham S Strong T 1974 Human arsenic exposure in relation to a copper smelter Environ Res 176 182 Minutes of Meeting of the Threshold Limits Committee ACGIH March 11-12 1965 Washington NIOSH files Minutes of Meeting of the Threshold Limits Committee ACGIH March 30-31 1967 NIOSH files 7 Minutes of Meeting of the Threshold Limits Committee for Chemical Substances in the Workroom Environment ACGIH Nov. 16 117972 NIOSH files Minutes and Agenda notices of the TLV committee meetings April 1-2 and Nov. 19-20 1970 April 8 a9nd Nov. 18 119971 April 13 and Nov. 16-17 1972 May 3 a4nd Nov. 1-2 1973 April 16 1a7nd Nov. 20 211974 May 6 a7nd Nov. 25-26 1975 April 28 2a9nd Dec. 6-7 1976 NIOSH files 558 Castleman and Ziem Morgan JF 1972 DuPont Letter to H. Stokinger June 6 1972 with attached copy of letter from D.H. Zeller BASF Ludwigshaven to Dr. J. Zapp DuPont April 13 1972. Morgan JF letter to H. Stokinger June 6 1972 with report of Pell S. An Epidemiological Study of Dimethyl Sulfate and Cancer of the Respiratory System 4 pp NIOSH files Morgan L 1972 Chief Med Officer International Nickel Ltd. Letter to E. Mastromatteo Ontario Dept. of Health April 17 1972. NIOSH files Date confirmed by Dr. Henschler Jan. 20 1987 Notice of Intent 1965 Jan. 7 1965 NIOSH files Noweir MH 1986 Occupational health in developing countries with special reference to Egypt Am J Ind Med 9 125 141 Occupational Exposure to Inorganic Arsenic Final Standard 1978 Occup Safety and Health Admin Fed Register 19584 19631 Official Assails National Cancer Institute Apr. 6 1974 New York Times Ott MG Townsend JC Fishbeck WA Langner RA 1978 Mortality among individuals occupationally exposed to benzene Arch Env Health 3 10 Paustenbach D Langner R 1986 Corporate occupational exposure limits the current state of affairs Am Ind Hyg AssocJ 809 818 Perry K Bowler RG Buckell HM Druett HA Shilling RSF 1948 Studies in the incidence of cancer in a factory handling inorganic compounds of arsenic II Clinical and Environmental Investiga- tions Br J Ind Med 6-15 Picciano D 1979 Cytogenic study of workers exposed to benzene Environ Res Pinto SS March 23 1961 Letter to H.E. Stokinger NIOSH files Pinto SS Bennett BM 1963 Effect of arsenic trioxide exposure on mortality 583-591 33 Arch 38 Environ Health Pinto SS Nelson KW 1976 Arsenic toxicology and industrial exposure Ann Rev Pharm Tox 95 100 PVC Rolls Out of Jeopardy into Jubilation Sept. 15 1976 Chem Week Report of the Committee on Threshold Limits Mar. 27-30 1948 Trans of the Tenth Annual Meeting of the American Conference on Governmental Industrial Hygienists Boston pp 29 31 Report of a Discussional on Threshold Limit Values held at Mellon Institute on February 1-2 1966 Confidential draft March 1966. NIOSH files 2 pp Review of TLV for Inorganic Lead 11 1970 AIHA Meeting NIOSH files Rosner D Markowitz G 1985 A Gift of God The public health controversy over leaded gasoline during the 1920's Am J Pub Health 344 352 Samuels SW 1981 The international context of carcinogen regulation benzidine Banbury Report 9 Quantification of Occupational Cancer New York Cold Spring Harbor Laboratory pp 497- 512 Scott R June 11 1978 Danger of level benzene reported Washington Post Spirtas R Steinberg M Wands RC Weisburger EK 1986 Identification and classification of carcino gens Amer J Pub Health 1232 1235 Stokinger HE March 2 1961 Letter to SS Pinto Asarco Not to be sent to files NIOSH files Stokinger HE April 1 1964 Letter to FG Stephenson Manufacturing Chemists Association NIOSH files Stokinger HE May 3 1966 Letter to RJ Sherwood Esso U.K. NIOSH files Stokinger HE March 8 1966 Letter to WA Knapp Allied Chemical Corp. NIOSH files Stokinger HE 1969 Current problems of setting occupational exposure standards Arch Environ Health 277-281 Stokinger HE Feb. 16 1972 Letter to Emil E. Christofano Hercules Inc. cc Standard Oil ICI America and Mallinckrodt Chemical representatives NIOSH files Stokinger HE June 11 1973 Letter to John Stender OSHA Administrator U.S. Dept. of Labor NIOSH files Stokinger HE 1986-87 Personal communication to B. Castleman Note Frequent reference is made to the Documentation of Threshold Limit Values and Biological Exposure Indices 5th Ed American Conference of Governmental Industrial Hygienists Cincinnati 1986. Also cited are the various annual TLV booklets published by the ACGIH No citations are given for such references either in the text or bibliography Many of the annual lists of TLV's and historic articles on TLV's have been republished in Threshold Limit Discussion and Thirty Year Index with Recommendations Ann A.C.G.I.H. Vol 9 Cincinnati 1984 Corporate Influence on TLYS 559 Stokinger HE May 19 1970 formal meeting for review of the TLV for inorganic lead NIOSH files Stokinger HE April 1968 TLV committee changes in the list for 1968. NIOSH files Torkelson TR Dyen F Rowe VK 1961 The toxicity of vinyl chloride as determined by repeated exposure of laboratory animals Amer Ind Hyg Assoc 3 354-361 Toyama T 1985 Permissible and control limits at places of work in Japan Amer J Ind Med 87 89 Vigliani E et al 1977 Methods Used in Western European Countries for Establishing Maximum Permissible Levels of Harmful Agents in the Working Environment Fondazione Carlo Erba Milan Vorwald AJ Durkan TM Pratt PC 1951 Experimental studies of asbestosis Arch Ind Hyg Occup Med 1-43 Vorwald AJ May 7 1952 First Interim Report Asbestosis and Pulmonary Cancer To Quebec Asbestos Mining Assoc Saranac Laboratory Saranac Lake N.Y. Vorwald Archives Armed Forces Institute of Pathology Washington D.C. Vorwald AJ 1948 Saranac Laboratory Letter to Dr. A.J. Lanza Metropolitan Life Insurance Co. Dec. 6 1948 and letter from Lanza to Vorwald Dec. 14 1948. Obtained from files of Manville Corp. by the U.S. Justice Dept. Wade N 1976 NAS committee on asbestos discovery of a special relationship Science 661 664