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69 ASBESTOS Part II: Occupational Safety and Health Agency/National Ins~i tute for Occupational Safety and Health A. BACKGROUND AND CONTEXT le Describe the chemical and its usese Asbestos is a general term for a group of naturally occurring hydrated mineral silicates that separate into fibers. Asbestos minerals used commercially include chrysotile, amosite, croc idol ite, tremor ite 9 ac t ino lite, and anthophyl 1 i te ashes tos . Since asbestos is highly resistant to heat, has high tensile strength, and moderate to good chemical resistance, it has many uses. These include asbestos-cement pipe, asbestos paper, friction products, vinyI-asbestos floor tile, paints, coatings and sealants, and gaskets and packings. 2. Describe how the question of risk was elevated to the agency leve 1. By the late 1960s, extensive scienti f ic documen tat ion 1 ead to widespread awareness and concern regarding the dangers of asbestos to workers . The Qrganizat ion o f Chemica 1 and Atomic Workers (OCAW) union was publicly critical of what it perceived as flagrant industry violations of good incus trial hygiene practices, as indicated by the American Conference of Governmental and Industrial Hygienists standard of 12 fibers/cc. The asbestos issue had clearly come into the political limelight by 1970. During congressional discussions of the Occupational Safety and Health (OSlI) Act, asbestos was highlighted on both floors of Congress as a primary example o f the kind of hazardous exposure from which workers needed protection.
70 Asbestos was included in the initial promulgation o f Occupational Safety and Health Administration (OSHA) standards on May 29, 1971, a month after the agency came into existence. At that tire, an exposure limit was set at 12 fibers per cc or 2 million particles per cubic foot of air. A. petition for an emergency temporary s tankard to control concentrations of asbestos dus t at more stringent levels was submitted to the Secretary of Labor by the Industrial Union Department (luff) of the AFI`/CIO on November 5, 1971. As a result of that petition, an emergency temporary standard of 5 fibers per cc of air was published by OSAKA on December 7, l9JI. This was followed on January 12, 1972, by OSHA's publication in the Federal Register of a "notice of proposed rulemaking" ~ NPPM) for a permanent standard of 5 fibers per cc. On January 24, 1972, OSHA established an Advisory Committee on Asbestos Dust and charged its members to make recommendations with regard to the proposed standard. A criteria document on asbestos, which contained recommendations for a permanent asbestos standard, was submitted by the National Institute for Occupational Safety and Health (NIOSH) to OSHA on February I, 1972. NIOSH recommended a 2 fiber per cc permissible level of exposure, to become effec- tive two years after promulgation of a permanent standard. On February 25, 19729 OSHA's Advisory Committee on Asbestos Dust, by narrow margins endorsed the NIOSTI recorma-endation~. OSHA held public hearings during the period March 14-17, 1972, to receive data, views a and arguments from interested parties concerning the proposed asbestos standard. A "permanent" s tandard for occupa- tional exposure to ashes tos dus t was published in the Federal Register on June 7, 1972. The regulation es tablislled a permis- sible occupational exposure level of 5 fibers ~ longer than 5 micrometers) per cc of air, which was to be lowered to 2 fibers per cc after four years. Less than two months after promulgation of the s tandard, the BUD of the AFL/CID, along with other unions, filed suit (July 28, 1972) in the U. S a Court of Appeals challenging the regulation. Among other allegations, it charged that OSHA's decision to delay implementation of the two-fiber exposure limit for four years (unti 1 July 1, 1976 ~ violated "highes ~ degree of health protection" under section 6(b) (5) of the OSH Act. On April 15, 1974, a three-judge panel in the U.S. Court of Appeals for the District of Columbia ruled in the case, in effect, denying the IUD petition but ordered OSHA to: ~ Review the 1976 implementation date for the two-fiber exposure level requirement, suggesting that OSHA might require the two-fiber level In those sectors of the industry where it was already feasible to achieve; and
71 Provide ~ longer period for the retention of personal and environmental monitoring records. (The standard, as pro- mulgated, provided for a three-year retention period. ~ In response to the court-remanded issues, OS'dA elected to initiate rulemaking. As indicated in the October 9, 1975 Federal Register notice: It is OSHA's belief that the record of the 1972 asbestos standard proceeding is inadequate to properly resolve the the two issues raised by the court's remand and that in the interest of achieving the best feasible occupational Wealth protect ion a new rulemaking proceeding should be initiated so that fresh and more detailed evidence may be developed regarding changes in industrial usage, compliance capabilities, and employee health practices which have oc- cured since the Standard 's promulgation over three years ago. In not taking any action earlier and then deciding to initiate a new rulemalcing, OSHA effectively prohibited application of the two-fiber standard prior to July 1, 1976. lrhe NPRM went beyond the court-remanded issues and addressed several others. In addition, it called for Lowering the standard of exposure to 0.5 fibers/cc with a ceiling of 5 fibers/cc for any period not exceeding 15 minutes. There was no discussion of when or if the proposed 0. 5-fiber standard would be feasible. Closing date for comments on the 1975 proposal was extended twice and ended up at April 9, 1976. In the meantime, on December 1, 1975, OSHA requested that NIOSH reevaluate the health effects data on asbestos. A revised criteria document '~as prepared and completed in December, 1976. The NIOSH recommendation stated that the asbestos standard should "be set at the lowest level detectable by available analytical techniques. " NIOSH defined this level as 0.1 fibers per cc. As far as could be determined, no further action was ever taken on the 1975 NPRM. Hearings were never held. 3. Under what statutes and agency jurisdiction does the chemical fall? That statutory tes ts governed the decis ion? The chemical falls under the jurisdiction of the Occupational Safety and Health Act of 1970. The t2 fibers/cc standard was promulgated under Section 6( a) as a "consensus s tandard" not requiring any rulemaking . The "emergency temporary s randard" 0 f fibers/cc was promulgated without rulemaking under Section 6( c) . The "permanent standard" of 5 fibers/cc ~ lowered to 2 fibers/cc after four years) was promulgated under Section 6~. Rulemaking is required for permanent standards, and the standard should be stringent enough to provide total worker protection f or 30 years of exposure to the extent feasible based on latest information. Section (20) calls for NIOSH to produce criteria documents with recommendations that protect the worker for 30 years based on health cons iderat ions a lone .
72 40 What was the decision schedule? Note any statutory or other action deadlines. Action - Initia1 promulgation of 05aA 12 fibers/Be standard Emergency temporary ~ tandard of 5 fibers/cc published as result of AFL/CID petition SPRY for "permanent'' 5 fibers/cc s tandart NIOSH submits Criteria Document to OSHA Fina 1 rut emaking f or 5 f ibers / c c standard which would be lowered to 2 fibers/cc on July 1, 1976 AFL/CID suit challenging four-year delay of 2 fiber/cc implementation Court remand to OSEA to review the 1976 2 fibers/cc implementation date OSHA initiates new rulemaking (NPRM) in response to court's remand NIOSH submits Criteria Document to OSHA C CRARACTERIZATION OF RISK ro HUMANS o (Sections B and C were combined.) 1. What health endpoints were evaluated? 1972 NIOSH Criteria Document May 29, 1971 Dec. 7, 1971 Jan. 12, 1972 Feb. I, 1972 June 1, 1972 July 2B, 1972 April 15, 1974 Oct. 9, 1975 Dec. 1, 1976 Primary emphasis was on asbestosis, with some consideration of bronchogenic cancer and mesothelioma . 1976 NIOSH Criteria Document Emphasis was on mesathelioma, lung and gastrointestinal cancers.
73 2. Mat were the key data available for review? (What additional data were sought? ~ 1972 NIOSH Criteria Document The British Occupational Hygiene Society (BOBS) study of asbes- tosis incidence in British factories was the chief document used in the development of the asbestos standard. Numerous epidemio- togic studies dealing witch lung cancer and mesorhelioma incidence were also reviewed. 1976 NIOSX Criteria Document Various epidemiologic studies for lung cancer, cancer of the G.I. tract, and me~othelioma were evaluated. References are listed on pp. 88-91 of the document. Also, a paper by Schneiderman ~ 1974) which critiqued two recent papers (McDonald, 1973, and Enterline _ al. 1973) was ir~f~luentiat. The two papers in question supported the idea of a threshold level for asbestos cancer induction. Schneiderman concluded that these data did not provide evidence for a threshold or for a "safe" level of exposure. 3. To performed the initial analysis? (What was their back- grount? Available analytical resources? ) 19 72 Criteria Document The initial analysis was performed by four NIOSH staff scientists. No data are available on their areas of expertise. 1916 Cri teria Document The analysis was performed by two staff scientists. One had training in epidemiology and toxicology. The other was trained in epidemiology and incus trial hygiene. The latter did the analytical chemistry analys is in the document. 4. To what extent were results presented quantitatively? What factors influenced the degree of quanti f ication? 1972 Criteria Document In the BOHS s tudy, data on 290 ashes tos workers were f itted to dose-response curve and the conclusion was drawn that an accumulated exposure of 100 fiber-years/cc (2 fiber~/ce for 50 years) would reduce early clinical signs of asbe~tosis to less than 12. The NIOSH standard was directly based on this study,
74 assuming a 30-year wortclife; i.e., 3 fibers/cc for 30 years. Introducing a ''measure of prudence" factor to account for car- cinogenicity, the standard was towered to an average exposure of 2.0 fibers/cc. 1976 Criteria Document NIOSH concluded that ''evaluation of all available human data provides no evidence for a threshold or for a 'safe' level of asbestos exposure O " Consequently, it was decided that the standard should be set at the lowest level detectable by available analytical techniques. No quantitative risk assessment was performed. 5. How was uncertainty described in reaching final inter- pretations? Were crucial ass~p~ion~ made explicit? 1972 Criteria Document A cancer "safety factory' was introduced by causing the s tandard to be reduced from 3 fibersicc to 2 fibers/cc. No Justification was given for choosing such a factor, and no data on cancer health risk to workers was estimated based on the new standard. 1976 Criteria Document Uncertainty was not addressed. By 1976 NIOSH endorsed the non- threshold theory of cancer. The document states: There are data that show that the lower the exposure, the lower the risk of developing cancer. Excessive cancer risks have been demonstrated at all fiber concentrations studied to date. Evaluation of all available human data provides no evidence for a threshold or for a "cafe" level of asbestos exposure. 5. How were qualitative factors dealt with? In 1972, there were two schools of thought regarding research approaches toward the identification and characterization of ashes tos related di ceases . One school supported an epidemic logic protocol for determining asbestosis. The other focused on epidemiologic evidence of cancer. NIOSH gave most weight to the former approach in 1972. Cancer was considered to be an important ef fee t, Tut OSHA/NIOSH supported the idea of a threshold value for cance r . By 1976, cancer was considered to be the most important and serious ef feet . NIOSE supported the nonthresho Id theory of cancer a
75 7. What qualitative factors affected the weighting of data? Were such criteria explicit and in accord with anv general guide- lines? The question of thresholds was key to the weighting of data ~ see Q. C . 5 and Q . C .6 ~ . The threshold theory of cancer, maintained by NIOSH in 1972, was supported by a 1971 National Academy of Sciences (NAS ~ s tudy which stated that "the appearance of a gradient or effect suggests that there are levels of inhaled asbestos without detectable risk. " However, the Surgeon General of the United States twice ~ in 1968 and 1970) endorsed the nonthreshold concept for carcinogens. The nonthreshold theory of cancer, maintained by NIOSH in 1976, was stated as NIOSH policy in May 1975. At that time, Dr. Fairchild, the Director of NIOSH, quoted the Surgeon General's 1968 statement in order to justify slitting standards for carcinogens to the lowest feasible level. 8. Describe any internal, internal-advisory, and external scientific review of the initial analysis. What, if any, criticism was incurred? 1972 Criteria Document The initial document was completed by NIOSH s taff with input from selected outside sources. The document was reviewed externally by three research scientists and doctors familiar with asbestos- related diseases. The revised document was then reviewed by selected representatives of professional societies (e.g., American Occupational Medicine Association, American Industrial Hygiene Association). These reviewers were independently appointed by the societies they represented. The next level of review was an internal review by the Director of the Institute and other senior NIOSH s taf f . All comments from previous reviewers were organized into a table delineat ing which comments had been Hiccup ted and which rejected. lithe senior committee went over all the comments and the rationale for responding to them in a particular way. The ma jor criticism incurred dealt with NIOSH' s focusing on asbestosis data rather than on the data dealing with cancer. 19 7 6 Cri teria Document The review process was similar to that of the 1972 document. The 1976 document was based entirely on the premise that there was no safe level of exposure to asbestos. It has not been determined whether this position was critized during review. However, as of May 1975 the nonthreshold theory of cancer had been es tabli~hed NIOSH pal icy .
76 9. How were issues raised in the re~riawks) accommodated? 1972 Criteria Document cancer "safety factor" was added after a standard was established Cased on ashestosis data. 1976 Criteria Document See Q. C O 8 10. Mat other issues arose concerning scientific late and their use? Br ie f ly de sc ribe di s sent ing opinions Industry was highly critical of the 1916 document. Representa- tives s tated that the NIOSH presented no dose-response information to demons bate that any exposure to ashes tos was unsafe. 11. Is the substance sub jec t deco Pas ~ or possible future regulatory actions ~ =_ ordinate with other agencies or programs? Asbestos is subject to possible regulatory action by EPA and Consumer Product Safety Commission. There was an ashes tos working group establ ished by flue Interagency Regulatory Liaison Group to coordinate activities under the Carter Administration, but this group was disbanded in September 1981. 1) o INTE RPRE'rATION I. What role did risk as sessment have in the f inal agency document where standards were established to control the chemical? The 1972 NIOSlI criteria document played a key role in supporting the final OSAKA rule establishing a permanent standard of 2 fibers/cc (FR, June 7, 1972) . As described in Q. A. 2, OSHA endorsed the NIOSH recommendation prior to issuing the rule. It is hard to determine the role the 1976 NIOSH criteria document played in supporting ache proposed rule establishing the 00 5-r'iber/cc standard (FR, Oct. 9, 1975) . It was published more than a year after the proposed OSHA rule and called for an even more stringent standard (O. 1 fibers/cc). No further action on the proposed rule was taken.
77 2. Were there variations--over tim ache f ina l ri sk as ses sment? There were variations over t ice, but there was apparent con- si~tency across agencies. In 1968 and 1970, the Surgeon General of the United States stated unequivocally that thresholds for carcinogens did not exist. In 1972, the NIOSH criteria document and an EPA rule for national emissions standards recommended or established exposure levels for asbestos consis tent with a threshold value for asbestos carcinogenesi~. In flay 1975, Dr. Fairchild, the Director of HIOSX, quoted the Surgeon General's 1968 statement in order to justify setting standards for carcinogens to the lowest feasible level. At that time EPA Interim Guidelines (EPA, 1976, Albert et al. 1971) called for the use of the linear nonthresho Id dose-response curve. These variations were significant to the f ina1 risk assessment as explained in previous questions. 3. To the extent there were issues/concerns about questions of science would the out come have been improved by coherent federal guide lines on care inogenic risk assessment, Federal guidelines could have established the scientific and policy bases for assessing cancer risk. Much of the confusion regarding statements about cancer thresholds, the use of data for asbestosis rather than cancer, and the use of a cancer "safety factor'' may have been reduced. Implicit assumptions regarding science and policy ques t ions may have become more evident. E. PERFORMANCE CONSIDERATIONS 1. Ab ility to obtain relevant scientific information Senior officials at NIOSH in 1972 stated that cancer studies published up until 1972 were inconclusive and ambiguous. Air sampling studies had been performed by different methods which made intercomparison difficult. In the view of one official there may have been good unpublished data at that time. However, he s Pa ted the t NIOSH adhered to a s trio t pa l icy regard ing new scientific information which may have precluded the use of this new data. The policy asserted that new information, which had not yet been published in open literature for public criticism, could Only be included in the criteria document if i t were peer reviewed. In the view of this senior official, scientists are often unwilling to allow such a peer review as it may spoil the opportunity to have their data published later. By 1976, the body of information was much more extensive and readily obtainable.
78 2 O Credibility of assessments, 1 ikelihood that interested parties would accept them as def initive . ., For the most part, industry was satisfied with a 5-fiber/cc standard as proposed by OSHA and as set by ACGTH g ant did not dwel ~ very much on health arguments. There was disagreement within industry with the argument that 2 fibers/cc was needed to protect the heal th o f workers O Some c [aimed that there was no evidence for hazard at low levels since current and recent incidences of disease resulted from past exposures at far higher concentrations. This opinion was given further support in an industry-sponsored study by McDonald (1973) who claimed to have evidence that only high exposure caused cancer. By 1975, however, the 2 f ibers/cc s tandard was widely accepted . ()n the other hand, labor was very dissatisfied with the proposal of 5 fibers/cc. Mention was made of the fact that the British Occupational Hygiene Society suggested a level of 2 for chrysotile but O. 2 for crocidolite which is known to be associated with mesotheliomaO The Textile Workers Union wanted a standard that used engine- ering controls and good handling practices to push toward zero exposure. The AFL/CID testified in favor of a more s tringer~t standard than NIOSH had proposed in 1972 which was perceived as essentially an asbestosis standard. AFL/CID pushed hard for a cancer standards The 1975 NPRI1 and the 1976 NIOSH criteria document were more in line with labor's viewpoint. On February 4, 1976, some 65 representatives from companies and trade associations representing manufacturers and processors of asbestos products in the United States participated in a meeting held in Washington, D.C. They overwhelmingly endorsed 2-fiber level as attainable by application of engineering tech- nolog~y. However, they stated the proposed O. 5 fiber level was unnecessary impracticable and lacked medical justifications What was the extent of diversity of policy orientations , represented within the assessment group itself? What was the degree to which interes e pressures could be exerted from outside the assessment croup? What was the responsiveness of _ the assessment to these diverse interes ts? The group that wrote the 1972 criteria document were all NIOSH personnel. However, they received input from individuals representing quite diverse opinions. Dr. Selikoff, who had prepared a brief for labor for its 1971 petition to OSlIA for an emergency temporary s tandard, contributed to the initial document. Industry oriented professions 1 societies g such as the ACGIH, were intruded to cogent later in the review process. The incorporation of a cancer safely factor into the standard was probably in part a response to pressure from labor groups.
79 It appears that there was little policy diversity among the groups that prepared the l9 76 NIOSE document . 4. What were the time and resources necessary to complete the risk as sessment? 1972 Criteria Document In the opinion of one of the major architects of the document, 10-15 person years were needed in just the preparation and review. However, the criteria document covered more areas than a normal risk assessment. Guidance was given in air sampling methodology, medical surveillance requirements, labeling, protective equipment and clothing, and work prac tices . 1976 Criteria Document In the opinion of one of the authors of the document, perhaps 1-1/ 2 person years were needed to camp le te the document . Th is document was not as extensive as the 1972 document and basically dealt with a review of the health effects, sampling methods, and the proposed s tandard . 5. Responsiveness of assessment agenda to public concerns . . . ~ ~ Interest group concerns, 2rotesslona. . concerns, and emergence of new sc lent i f ic informa ~ ion. ~ . This question has been answered in Questions A .2, E.2, and E.3. 6. Ability o f the risk assessment to identify research needs . A consensus of opinion among interviewed NIOSH personnel was that the risk assessment did s simulate research to some degree, but that the chemical was of such universal interest that the influence was probably minor. 7. Extent to which risk assessment impeded or facilitated regulat ion The 1979 criteria document probably facilitated regulation by supporting the premise that there was a safe level of exposure and calculating what that exposure would be. It is difficult to determine the impact of the 1976 criteria document, since the proposed 1975 OSHA rule was not made f inal .
80 80 Were related risk assessments consistent? See Q. I).2. 9. Extent to which there is an explicit distinction between weight. accorded to scientific factors and policy factors. Lee asbestos example is a good one to i llu~trate the lack of distinction That can occur between scientific factors arid policy factors. In 1972, NIOSH did not accept the premise that any level of exposure to a carcinogen was unsafe. An NAS study in 1971 supported this conclusion. A contrary opinion was voiced twice by ache Surgeon General of the United States in 1968 and 1970. He Stated that since there is no threshold level for a carcinogen, any level must be deemed to be unsafe. Indeed, OSlIA, in 1971, referred to the Surgeon General ' ~ statement when promulgating its consensus standards. There is no documentation as to why NIOSH chose the NAS view over that of the Surgeon General. By 1976, NIOSH had changed its position, Treating cancers as non~hreshold subs tances a In f act, Dr. Fairchi id of NIOSH justified this position in 1975 by quoting from the 1968 Surgeon General' ~ statements lOo Mode and frequency of communication between assessors and regulators a There was frequent communication between OSHA and NTOSlI during promulgation of the asbestos standards. OSHA officials were invited to peer review meetings, and a record of all review comments and responses was submitted to OSAKA as part of the of f ic ial record .
81 SOME: IMPORTANT REFERENCE S CITED Albert, R. E., R. Train, and E. Anderson. 1977. Rationale developed by EPA for the assessment of care inogenic risks. J. National Cancer Inst. 58 :1537-1541. BOBS (British Occupational Hygiene Society). 1970. 1969 Standard for asbestos dust concentration for use with the asbestos regulations. Department of Employment and Productivity, Her Majesty's Factory Inspectorate. Technical Note 13. Enterline, P. E. and V. Henderson. 1973. Types of asbestos and respiratory cancer in the asbestos industry. Arch. Environ. Health 27:312. EPA (Environmental Protection Agency). 1976. Health risk and economic impact assessments of suspected carcinogens: interim procedures ant guidelines. Federal Register 41: 21402-21405. McDonald, A. I)., 1). Wagner, and G. Eyssen. 1913. Primary malignant mestothelial tumors in Canada, 1960-1968. Cancer 31:869. NAS (National Academy of Sciences) . 19 71. Asbe~tos--The need for and feasibility of air pollution controls. Schneiderman, M. A. 1974. Digestive sys tem cancer among persons subjected to occupational inhalation of asbestos particles. A literature review with emphasis on dose response. Environ. Health Pers. 9:307.