Document V9Ozwrr3QM87n1jVr5QKRz6w

PPG INDUSTRIES, INC./ONE GATEWAY CENTER/PITTSBURGH. PENNSYLVANIA 15222/AREA 412/434-2585 2EB G. BELL. JR., Sc D.. Manager Environmental Health and Toxicology Chemical Division March 31, 1976 Docket Officer Docket H-033 . U.S. Department of Labor Room N-3620 200 Constitution Avenue, N.W. Washington, D.C. 20210 wT Dear Sir: PPG welcomes-the opportunity to comment on the Department of Labor's proposed standard on occupational exposure to asbestos which appeared on Thursday, October 9, 1975, Federal Register pages 47652 through 47665. PPG is a significant user of asbestos for the conventional application for its thermal insulation properties for high temperature steam and power generation, catalytic and thermal process units and for the prep aration of diaphragms in the production of chlorine and caustic by the electrolysis of brine, as well as other products in the construction and building trades. It should be noted that chlorine and caustic are presently restricted to either diaphragms or mercury cell facilities. We do not intend to comment here on the future of the mercury cell installation from both the EPA and 0SHA. There is a misconception that there are immediately available substitutes for diaphragm cells other than asbestos. Diaphragms of materials other than asbestos are in the early development stage and 0SHA should not be falsely lead to believe that substitutes are readily available, in widespread use, now or will be even in the very near future. At this point In time, asbestos is the only acceptable material for cell diaphragm construction and will be for years to come. PPG has employed substitute materials of construction wherever these have been feasible; however, asbestos is presently a must for diaphragms in the electrolysis of brine. We are also concerned that very stringent and burdensome requirements may make asbestos unavailable for diaphragms in the United States. Docket Officer March 31, 1976 Page 2 If the proposed standard impacts upon the producers of asbestos SO that they decide to discontinue its sale, then the production capacity of chlorine and caustic will be severely curtailed. Approximately 80 per cent of the U.S. production of chlorine and 80 percent of the sodium hydroxide is made in diaphragm cell facilities. Chlorine and caustic is the basic conmodity of PPG Industries Chemical Division's entire product lines. The total impact upon PPG in view that the production of chlorine by the mercury cell process is also under heavy pressure cannot and should not be underestimated. PPG Industries Chemical Division's entire assets with its 3,625 employees in four states would be adversely affected if standards are unjustifiably and unscientifically promulgated. We urge OSHA to weigh heavily the camifications upon the chlorine/caustic industry. In addition to our own facility and operations, the repercussions would impact upon the paper and aluminum industries that rely upon sodium hy droxide. The varied uses of chlorine are well known and will not be expanded here; however, we believe the evaluation of the economic and health impact must also include the consumers of chlorine including the past treatment of waste and water purification. The above discussion is intended to enlighten OSHA of the importance of asbestos in the production of chlorine and caustic. We have reviewed the standard and are aware of the deliberations for lowering of the permissible exposure to asbestos. It has been stated in the proposed standard that the lowering of the permissible level of the time weighted average to 0.5 fibers of asbestos per millimeter of air was based on "new medical and scientific evidence" which had become available since the last asbestos standard was promulgated in 1972. Attached is a scientific appraisal of this "new medical and scientific evidence" by Hans Weill, M .D. Also attached is Dr. Weill's curriculum vitae. Dr. Weill's appraisal states that the "new evidence" does not support lowering the standard below 2 fibers per milliliter of air. We agree with his analysis of the "new evidence"; his opinion in regard to it, and his recommendation that the 2 fiber per milliliter standard should be given a reasonable trial while further epidemiological inves tigation establishes its safety or lack of it. It has also been stated in the proposed standard "that in considering the controversial issue of carcinogenicity that OSHA is not only relying on the new evidence discussed above but leading scientific principles and opinions believed to reflect the research conclusions of international cancer experts which were developed since or not known to OSHA at the time the original standards were promulgated." The three principles cited were latency, individual susceptibility, and threshold limit. The first two principles have been well known and understood for many years. The latter principle threshold limit as applied to carcinogenic ity is understood by the public in relationship to cigarette smoking. Docket Officer March 31, 1976 Page 3 For example, the public has been educated to understand that a person must smoke a pack of cigarettes or more a day to appreciably increase his chances of getting lung cancer. The logic that NIOSH used in employ ing these three principles to recommend the 0.5 fiber per milliliter standard is not readily apparent and does not appear to have a rational basis. We also sense that certain members of the scientific community advocate no exposure to asbestos and if OSHA has in mind subsequent lowering of the permissible limit, they should determine the adverse economic impact upon the industry now as well as in the light of future reductions of the permissible exposure limit. It is submitted for the record that the Chemical Division of PPG has used asbestos in diaphragm cell circuits for over 40 years, and we have no cases of asbestosis and no known cases of mesathelioma. This informa tion cannot be ignored in OSHA's promulgation of the final standard. To our knowledge, there have not been any reports or evidence that asbestos used by the industry in diaphragm cell construction has resulted in any increased risk of the disease associated with asbestos. It is submitted by PPG that asbestos as used in the preparation of dia phragms should be regulated by a work practice procedure rather than a numerical value for airborne concentrations. PPG submits these specific comments on the proposed asbestos standard and recommends the following changes be adopted by the Department of Labor and reflected in the final permanent standard. Page 47660, Column 2 Definitions D "Asbestos" include* chryfotiie. mnoMtc. erocidoiiu. tremoiiu. nnihophvlliie. and actinollte. and every product containing any of these minerals. Comment (1): Page 47652, Column 3 provides the generic terms for the various forms of asbe3stos and certain ch, em.ica,l and, p.hys.ical, properties listed such as tensile strength, flexibility, heat and chemical resistance are parameters that cannot be used by the microscopists in the laboratory to identify the various forms based only on air samples. The existing standard required a field information memorandum #74-92 to differentiate the methods of analysis of fibrous forms (tremolite) in the presence of non-fibrous forms (talc). Subject Field Information Memorandum is attached. Recommendation: OSHA take cognizance of these deliberations and include as part of the definition of asbestos in relation to tremolite and talc. Docket Officer March 31, 1976 Page 4 Corrment(2): The definition of asbestos includes "every product containing any of these minerals", however, the standard does not reveal how this is determined. The use of "any" could be as restrictive as to mean even one fiber. Recommendation: There needs to be a lower limit of acceptable levels of these minerals in products otherwise there is no lower limit even for inherent impurities. The definition should be rewritten as follows: . . and every product that is likely to contain asbestos which in its use or preparation would result in exposure to the employee airborne levels in excess of the permissible limit.". Comment: The definition section fails to define such words as "contaminated" (h) (5) (6) and (7) and "uncontaminated" (i)(4) and (5) used in the proposed standard. Recommendation: Define "contaminated" as any visible evidence of asbestos fibers. Page 47660, Column 2 (b)(2) Asbestos Fibers <2' "Asbestos fiber" means a partialilnte form of asbestos, longer than 5 mtI crometers. with a len*lh-to-diamcter ratio of at least 3 to 1. and with a maxi* l mum dioxaelCLf 5 micrometers. Comment: This definition would infer that fibers 15 microns or greater are not important and should not be included in the determination for meeting the permissible exposure limit. A fiber 15 microns in length and 5 microns in diameter meets the requirement of 3 to 1 length to diameter criteria as well as being greater than 5 microns in length. A 5 microns fiber diameter must be at least 15 microns in length to be recorded. A fiber 100 microns with a diameter of 2 microns meets the criteria. Recommendation: The definition of fiber be rewritten to include maximum fiber length and maximum fiber diameter to be counted. Page 47660, Column 2 (b)(3) Emergency <3> 'Emergency" mcnns an unforesee able and unexpected occurrence HXely to release airborne concentrntlons of asbes tos fibers In excess of 5 fibers per cubic centimeter of air. suen as. but not limited to. failure of equipment or control derlces. and rupture of containers. Comment: We again do not believe a material that has only chronic health effects should be termed an emergency. As written now, an excess of 5 fibers per cubic centimeter of air has no time factor so it is an absolute determination. This interpretation is more stringent tr.an the permissible exposure limit. Recomnendation: Change "emergency" to "severe exposure" and refer to the permissible exposure limit instead of the 5 fibers. Docket Officer March 31, 1970 Page 5 Page 47660, Column 3 1910.1001 (c)(1) Permissible Exposures <c> Permissible exposure to airborne ronccntrn/lon.t of asbestos fibers--(]) thour t tme-nriphled averaoe concentra tion. No employer mny be exposed to Bn 8-hour tlmc-welchled average nlrbome concentration of asbestos fibers In excess <-.f OS fiber per euhlr rrntlmrLrr (or 500.000 fibers per cubic meter) of air. ns determined on the basis of a 40-hour work week and by the method prescribed In paragraph 'e'<3) of this section Comment: This paragraph needs clarification. Recommendation: This sentence be changed by adding after "air"--"appropriate reduction in the permissible 8 hour TWA exposure must be made for employees who work more than 40 hours per week." Delete the present wording. Page 47660, Column 3 (c)(2) Ceiling Concentrations (2' Ceiltng concentration. No employee mny be exjwed to nlrbome concentra tions of asbestos fibers In excess of 6 fibers per cubic centimeter <or 5 million*, fibers per cubic meter) of air. as deter . mined over a period up minutes, by the method prescribed In paragraph Comment: There is no definite evidence that peak exposures are any more detrimental to health than the cumulative total dose in the range covered by this standard. To regulate on a basis of a sample collected for a period <e* <3> of this section less than 15 minutes has many potential reper cussions not the least is recordkeeping. The exact period when a level might be the highest on a minute-to-minute basis reguires more data points through sampling. Unless there is evidence to dem onstrate otherwise the ceiling concentration should be deleted. Recommendation: Delete ceiling concentration definition, or at least specify that for the purposes of compliance, a sample must be collected over a 15 minute continuous period of time. Page 47660, Column 3 (d) Regulated Areas id* Repainted areas. Any work area where a i>crson may be exposed to air borne conce ninrtTon* of a-sbcsUxs fibers Corcment (1): The proposed standard does not differentiate between "may" and "is likely to" hi excess of either of the limits Imposed bv paragraph *c) of this section shall be [(e) middle of paragraph!? (Irvlrnnlcd a reguintrd nrca. Only nu- thoilxrd persons may be allowed to enter such an m en. * Hni)\ ; pster of all persons Reconmendation (1): Change "may" to "is likely to" entering a regulated area sTiall be made and maintained. Comment (2): 0SHA has not appreciated the extreme difficulty and added burden plased upon industry at construction sites to maintain a daily roster. Recommendation (2): Daily rosters be required for installations which are erected for a period of one year or more. Docket Officer March 31, 1976 Page 6 Page 47661, Column 1 (e)(2)(ii) Frequency <U> If monitoring shows thnt nn em ployee's exposure is below both limits prescribed In paragraph (d of thls_sectlon, the monitoring shall be repealed every three months, except as otherwise p?STHl6<r'irr~paragraph (e'<2)<l> or (e) Comment: To require quarterly monitoring of employees in the exposure below the permissible limit is unwarranted and unjustified by medical evidence. (2) (ill). or <c> <3> <iv> Of this section. Recommendation: When the results of monitoring are below the permissible limit, monitoring should be reduced to annually. Page 47661 , Col umn 1 (e)(2)(iv) Change in Process (It) Whenever an employer has rrnson to believe that an employee's level of fioosurt has changed because of a change In production, process, controls, or oUier relevant factors, the employee shall be monitored as soon ax practicable, and thereafter paragraphs (e> <2> (!), ie> (2) (11). or <e<2KUI> shall apply. ` Comment: This section fails to recognize that changes can result in decrease exposures as well as increased exposures. Recommendation: Reword section "whenever an employer or the employee has reason to believe that the employee's level of exposure has increased because . . Page 47661, Column 1 (e)(4)(1) Employee Notification (4) Employee notification. (1) Within five (5) working days after the receipt of the measurement results, the employer shall notify each employee In writing of the results concerning the employee's exposure. Comment: "Notification of an employee within five working days after receipt of the measure ment results. . ." This paragraph requires that employees be notified within five days of all the results of monitoring not just those in the excess of the proposed standard. Recommendation: Reword "within five working days measurement results of overexposure, the employee ..." Page 47661, Column 2 (f)(2) Personal Protection Controls 2> Personal protection controls. Where engineering and work practice controls are not sufficient to reduce em ployee exposure to or below the permis sible exposure limits, they shall nonethe less be used to reduce exposure to the lowest possible level, and shall be sup plemented "By~The"use of respirators, in accordance with paragraph (g) of this section. Recommendation: Change "Possible" to practicable". Docket Officer March 31, 1976 Page 7 Page 47661 , Column 2 (f)(3) Particular Tools (3) l'articular tools. All lmnd-opcrntcri und power-operated tools which mny produce or release asbestos fibers in excels of the exposure limits pre scribed In paragraph <c> of this section, such as. but not limited to, saws, scorers, abrasive wheels, and drills, shall be pro vided with local exhaust ventilation sys tems. Recommendation: Reword all power tools used shall be equipped with local exhaust ventila tion for operations such as, but not limited to saws, scorers. . . All hand tools that cause, or are likely to cause, airborne levels in excess of the permissible exposure limits shall not be used without devices to control releases. Page 47661, Column 2 (f)(4)(i) Work Practices < 4' Work practices. (1) IVcf methods. Insofar as pracUcablc, asbestos shall be liniiUlrU, mixed, nppllcd, removed, cut. scored, or otherwise worked In a wet state sufficient to prevent the emission of airborne fibers In excess of the ex posure llmtLs prescribed In paragraph <c> of this section, unless the usefulness of the product would be dlmtniSTfpd thereby. Comment: Although we concur with the general wording, this paragraph needs several additional words inserted. Reconmendation: . . ., unless it can be demonstrated the usefulness of the product would be diminished thereby. Page 47661, Column 2 (f)(6) Mechanica1 Ventilation <6> Mechanical ventilation. When Comment: It is reasonable to require periodic mechanica) ventilation Ls used to control exposure, measurements which demon strate the effectiveness of the system to control the exposure, auch as capture velocity, duct velocity, or staUc pressure, shall be made at least every 3 montlrs. inspections and checks of mechanical ventilation systems that are used to control the exposures below the permissible level. If, however, such controls would not result in airborne concentra Measurements of the system's effective ness to control exposure shall also be made within 5 days of any change In tions in excess of the permissible exposure, the equipment need not be routinely checked. production, process, or control which might result in any change In employee exposure. The frequency of such checks not be required if their failure would not result in employee exposures in excess of the permissible exposure limit. Many employers provide mechanical ventilation as an added measure even where the permissible exposure limit is not exceeded. These installations where failure of mechanical ventilation would exceed the standard. This requirement will induce the employer to remove the mechanical ventilation rather than maintai it under the above stated conditions. Recommendation: Mechanical ventilation used to control employee exposures below the permissible exposure limit shall be checked after initial installation, alter ations and/or maintenance that is likely to result in decreased operating efficiency of the ventilation system or an increased exposure. Docket Officer March 31, 1976 Page 8 Page 47661, Column 3 (g)(1) Respiratory Protection <R> Respiratory protection. <1> Use. Respirators shMI be used where required under this section. Compliance with the j>ermlsslble exposure limits may not be achieved by the use of respirators, exrept: Comment: It is our position that intermittent work such as opening one bag of asbestos, hot patching one small area and other similar situations should be permitted to be accomplished using respirators. Recommendation: Add a section (iv) that permits intermittent use of respirators provided. The task cannot be accomplished as specified elsewhere in the standard. Further, the wording of this paragraph means that where engineering and work practices cannot lower the levels to or below the permissible exposures, then such situations by definitions constitutes an "emergency" such as interpretations would be inconsistent with the definition of emergency, (b)(3). An uncorrectable but known excess of the standard should not constitute an emergency. Page 47662, Column 1 (g)(2) Table 1 -- Selection of Respirators Cp U> 60 Unit* Uif applicable fxjmure limit prescribed Id paragraph (r) of lhl section Dp to JO lime* lhe applicable eipruur* limit prescribed In paragraph (c) of VhU section. (A) A high efficiency particular niter respirator with a full facepiece; or (D) Any supplied air respirator with a full fareplece; or (C) Any self contained breathing apparatus with a full face* piece. IAI Aliy air purlfjkug jc.-pwator IUi replaceable particulate niter; or (Bj Any ilngle use respirator with or with* out T&ive; or (C) Any supplied air respirator; or (D) Any self contained breathing apparatus 'High efficiency niter--P9 87 percent efficient against 0.3 micron alza dloctylphlhalate (DOP). Comment: High efficiency respirator filters are needed for toxic materials where the particle size is not the governing factor. The asbestos standard is concerned with only the large fibers and not submicron size fibers. High efficiency filters have an inherent disadvantage, that is, they are accompanied by higher resistance to breathing as a result of the increased pressure drop across the filter. With increased pressure drop across the filter, more important becomes the facial fit of the respirator. It would appear that high efficiency filters afford no more protection and possibly impose a greater risk of facial leakage than respirators of less pressure drop but with excellent filtering efficiencies for particulates regulated by this proposed standard. Docket Officer March 31, 1976 Page 9 There is no justification to require respirators for asbestos to meet the high efficiency filter criteria established in footnote (1) using dioctylphtholate. It seems contradicted for asbestos. Unless there is medical evidence that submicron asbestos particles are as hazardous to health as larger fibers, then this requirement should be deleted. Recommendation: The high efficiency respirators be deleted from this standard and that air purifying respirators be approved for use up to 200 times the applicable exposure limit. Change Table 1 to reflect this change. Page 47662, Column 1 (q)(3)(iv) Respiratory Program To the maximum extent passible, such em ployee shall be routed to anoUicr Job. or given the opportunity to transfer to a different naitinn wha.se duUts he 15 able to perform^ wtUi the inmc employer. Comment: The Department of Labor has required that no employee be transferred or rotated from one job to the other in that he not retain seniority, etc. In the same geographical arrn and with the same seniority, rtntus. and_rat_or pay he had Just prior lo sucTTlransler. It is PPG's position that 05HA has exceeded the jurisdiction of the Act as well as the intent of Congress when it begins to regulate items which are negotiable. Items such as described are union-management negotiated items and we do not feel that OSHA should or can dictate these to either the union or management. Recommendation: Insert a period after "perform" and delete remainder of the sentence. Page 47662, Column 2 (h)(4) Personal Protective Clothing 4) The employer shall assure that all protective clothing and equipment is re moved only In change rooms required by paragraph (1)0) of this section. Conment: If the exact wording of this section is enforced, it will be necessary that each time the employee removes his or her gloves, hard cap, apron, or respirator,'he must enter the change room. Recommendation: The employer shall require that all protective outer clothing are removed only in the change room. Docket Officer March 31, 1976 Page 10 Page 47662, Column 2 (h)(5) Personal Protective Clothing <5) The employer shall assure that no employee removes rnn^pminLrd dpoU>clivc clothing and equipment irom Uic elinnRC room. except for the purt>osc of cleaning. laundering, maintenance, or disposal. Comment: This section prohibits employees who enter the change room from reusing such items as gloves, respirators, hard cap, aprons and shoes without them being cleaned or laundered. We doubt that OSHA intended this interpretation, but we submit that this interpretation can be made. Recormendation: "Used or contaminated clothing left in the change room at the completion of a work shift can only be removed for the purposes. . ." Page 47662, Column 2 (h)(6) Contaminated Protective Clothing (6i conuimimrej^protective clothing nnd cermpuii'ni snail be placed in lm- permeable closed containers. Recommendation: Insert "or covered" after "closed" ' Page 47662, Column 2 (i)(1) Hygiene Facilities -- Change Rooms Ml Hygiene facilities and practices. 1> Chance rooms. Where employee* wear protective cloUilng and equipment, Comment: There are places of employment where protective clothing is provided because of clean change rooms equipped with stor age facilities for street clothes And sepa rate storage faclliUcs for protective negotiated contract with representatives of the Union. Where this is done and the exposure cloUilng and equipment shall be pro vided. limit of the standard is met, such facilities should be exempt from this requirement. Further, employers who provide additional protective clothing should not be penali zed by the standard where the employer has done more than is reguired because of such actions. Recommendation: Limit change room requirements where the permissible exposure limits are exceeded. Docket Officer March 31, 1976 Page 11 Page 47662, Column 2 (i ) (3) Lavatories " (3) Lavatories. Employers working In regulated arms shrill be required to wash hands, fare, and forennma prior to drink ing. eating, or smoking. The employer shall provide an adequate number of Invatorlcs for Oils purpose which shall meet Uic requirements of I 1910.141 id>ii) and <a> of uus part. Comment: According to the present language of section (d)(1) and (2), lavatories and wash facilities must be located inside the change room since eating etc. is not per mitted in a regulated area. Although we do not strongly object to the restriction of eating, chewing or smoking in regulated areas, there is no documented evidence to our knowledge that ingestion of asbest&s constitutes a hazard. Animals fed asbestos in large quantities over their normal life span did not suffer health impairment. Recommendation: Reword section to reflect this rationale. Page 47663, Column 3 (n)(3) Mechanical Ventilation (31 Mechanical ventilation measure ments. When mechanical ventilation Is used as an engineering control, the em Comment: Regular measurements of mechanical ventilation and the retention of records for ployer shall maintain a record of the measurements demonstrating the effec tiveness of such ventilation, as required three (3) years is without justification and adds to the administrative burden of the by paragraph (f)(6) of tills section. employer. The only justification for these records-is that the Department of Labor has realized that 05HA inspections of facilities using asbestos will only occur about every three years. Since mechanical ventilation especially for portable and semi-portable devices are more subject to changes in efficiency than installed general ventilation, this requirement for recordkeeping is noninfor- mative. The required quarterly checks will provide at least four past records for which OSHA can review. This should be more than adequate. Recommendation: The three years retention of records be reduced to one year. Alternate recommendation: "The records of mechanical ventilation installed to meet the permissible limits of this standard shall be retained for one year." Docket Officer March 31, 1976 Page 12 Page 47663, Column 3 (n)(5) Daily Roster Records -<3T TTOTfrM. Each rosier required by paragraph <d> of this srctlfln shall be maintained for at least 40 years or for the duration of the personnel s employ ment plus 20 years, whichever period Is longer. Comment: The accumulation of records of employee entry into regulated areas is an unnecessary burden upon the employee since regulated areas may be desegregated because of the "potential" exposure risk to employees and not because of the "actual" exposure. This data is uninformative without documentation of the levels of exposure. Where operations ore not permanent, such as removal of asbestos installation, the regulated area will be temporary. It is, however, important to retain airborne measurement records and only list those employees who are not routinely assigned to the regulated area. A summary of these should be permitted to reduce the enormous files that will be accumulated. Recommendation: Summary of the employees daily roster are required for employees who are not routinely assigned to the regulated area. Page 47663, Column 3 (n)(6) Record Availability (6' Arnilablhtv. <0 All records re quired to be maintained by this sccUon shall be made available, upon request, to Comment: The employer should be required to inform the employee of "actual overexposures" the Assistant Secretary and the Director for examination and copying. in writing, however, we object to the standard requiring the employer to inform the employee of all measurements including those below the permissible exposure. We also object because of the "potential" large number of requests for copying of records. It should be adequate to make the employee's own monitoring records available for examination and copying of his or -her own records at a reasonable cost. Change "representatives"to "representative" (singular). Recoimendation: Employee exposure . . . for examination of his or her own records. Copies of these records upon written request and nominal costs incurred by the employer shall be accomplished for employees, former employees and their designated representative. Page 47664, Column 1 (o)(l) Observation and Monitoring (o) Observation of rnonitorino. <1> Employee observation. The employer shall give employees or their representa tives an opportunity to onserve nny measuring or monitoring of Uirlr expo sure to asbestos fibers conducted pursu ant to this section. Comment: The employer shall include as part of the training program basic instructions of the monitoring program. The employee or his duly designated representative will be permitted to observe monitoring procedures where there is reason to suspect the procedures used by the employer are not proper. It is more important since most measurements will be personal sampling where the employees' cooperation is required. Although Docket Officer March 31, 1976 Page 13 participation in a medical surveillance program may be optional, cooperation of the employee in programs to determine his or her exposure should not be optional. Recommendation: Paragraph (o)(1) should be rewritten. "As part of the training program, each affected employee under this standard shall have explained and demonstrated the monitoring and analysis of air sampling for asbestos. It is obvious after a review of the proposed standard that the tenor and direction of OSHA is to subsequently lower the permissible exposure limit. This direction is apparent when specific sections of the proposed regulation imply that a single .exposure to asbestos above the permissible limit requires special precautions.^ PPG again emphasizes that the Department of Labor should not promulgate unnecessary restrictive regulations for which the risk/benefits have not been fully evaluated. The impact upon the production of chlorine and caustic and other operations of this proposed standard should be thoroughly appreciated. /elm Attachment Statement by Hans Weill, M. D. , on Rules on Occupational F'tposurc to Asbestos proposed by OSIIA (Docket No. i 1-0 3 3) By way of introduction, I am Professor of Medicine at Tulane University School of Medicine and direct a large interdisciplinary program in the investigation of occupational lung diseases. These research activities involve all varieties of inhalants including mineral and organic dusts and chemical vapors and gases. The goal of our program is to provide the scientific basis for the prevention of occupational lung disorders. Specific aims are to establish, whenever possible, causal relatioriships between environmental conditions and a definable biologic response, dose-response relationships, and threshold levels of exposure below which the adverse effect dees not occur. As an independent university-based research unit, our work is in large part supported through competitive federal funding mechanisms, including the NIH and NIOSH. Published results of our investi gations are available for peer review in the scientific literature. Because of the appropriate interest of responsible industry in protecting the health of their workers, a portion of our research activities has also been funded from industry sources. Our investigative interest in the health effects of asbestos exposure dates back approximately six years with a significant portion of this research having been accomplished with the collaboration of the Medical Research Council Pnnunoconios i s Unit in Britain. 2 I would like to make clear my role in submitting these comments on the proposed new standard for occupational exposure to asbestos. I was asked to prepare an objective, scientific .assessment of the literature cited by OSHA in support of its proposed standard change by the Asbestos Informa tion Association of North America. I accepted this consultative task because I firmly believe that industry, in order to meet its occupational health respon sibilities , must have available to them outside advice from academic and other sources. It is my objective in the following discussion to provide scientifically-hascd and dispassionate judgments on the issues raised and in no way assume an advocacy or adversary position. i There should be no doubt or confusion concerning the reasons or indeed justification for the setting of occupational health standards by regu latory agencies: these standards are set to protect workers exposed to environmental hazards in the work place. The standard-setting process should begin with a scientific data base providing quantitative information on the relationship between the environmental exposures and any associated hen 1th effects. Without data for both sides of tins equation for a particular health hazard, resulting information is incomplete in terms of the important function of setting standards for safe levels of occupational exposures. Al though these requirements have now been recognized by both government and non-governmental scientists, the fund of hard data of tins type which is 3 available is clearly limited. This deficiency docs not, of course, justify delay in the setting of standards vising the best available quantitative information, however incomplete. Nor docs our limited knowledge justify abdicating the role of science which is rationally applied to the problems of occupational health. Such a negative approach may be employed to support either extreme of little or no control on the one hand and unrealistically stringent control on the other, and is self-defeating and certainly counter productive. It is often forgotten that standards, like science, are not written in concrete and as scientific evidence provides more information on dose-response relationships, the standard setting process must be responsive by means of regulatory action in either direction. It is clearly stat- t cd in the published OSHA proposal that the lowering of the permissible level of eight-hour time-weighted average exposure to 0. 5 asbestos fibers per milliliter is based upon new medical and scientific evidence which has become available since the last asbestos standard was promulgated in 1972. My sub sequent remarks will focus on this "new evidence". There should be little debate concerning the causal association between occupational exposure to asbestos dust and certain adverse health effects, including but perhaps not limited to asbestosis, hronchogcnic carcinoma of the lung, mesothelioma of the pleural and peritoneal surfaces, and gastrointestinal neoplasms. Most references cited by OSIIA, dating 4 back to 1907, do not relate to the central issue, that being at what level (if any) of exposure do such effects fail to occur. Documenting that these health effects have occurred in workers who have had years of exposure to asbestos dust without relating measurement or reasonable estimates of past exposures to these effects has been of great importance, but docs not materially assist bn the standard setting process. It is respectfully suggested that the great majority of the 42 references cited in the proposal must be classified in this way. Because of the emphasis placed by the writers of this proposal on a few, mainly unpublished, recent reports, these will be reviewed in i some detail. Few studies have received as much attention and imputed importance in this standard setting process than the epidemiologic investi gation of a cohort of workers employed in an asbestos textile plant in the industrial midlands of England. However, it is with some dismay that our British colleagues view the current use of their data, which is in many ways incomplete, by scientists and regulatory agencies in the U.S. Certain facts seem indisputable. The initial report published by Professor Doll in 1955 demonstrated a clear excess in respiratory cancer and pulmonary fibrosis in workers who had previous exposure for 20 or more years in this plant (1A). Follow-up of mortality data published in 1968 provided evidence that workers having their initial exposure since the asbestos regulations 5 took effect in 1933 had a decrease in lung cancer and asbestosis mortality and even suggested that the hazard of bronchial carcinoma had been elimin ated in this population (13). It was clearly stated, however, that longer follow-up was necessary and "the data arc insufficient to estimate the extent of the risk winch may remain". While the improved health status of the more recently cxpqscd workers was encouraging, limited dust exposure data presented indicated that this cohort had been exposed to average levels of asbestos dust which were often higher than current U.S. or U. K. standards. The most recent update on the mortality experience of this cohort was presented at the International Congress on Occupational Health, .held in Brighton, England, in September, 1975 (30). Tins continued follow-up for an appropriately longer period of time revealed a modest excess of respiratory cancer in the working population first employed since 1933. Perhaps of greatest interest was that even in a sub-cohort comprising 255 men and 93 women entering the industry for the first time since 1951 and having more than 10 years exposure, five deaths from respiratory cancer were observed in individuals with more than 15 years since first exposure. The expected number would be 1.86, an excess which was statistically significant at p = .04. This risk was found to be greatest in those individuals having more than 20 years' exposure. Importantly, while it was indicated that major dust control measures were completed in this plant in the late 1950's, no specific 6 dust c.vposuro data wf-ro presented nor were claims made in regard to the utility of these results in setting safe standards or in generating doscresponse relationships between asbestos exposure and risk of developing respiratory cancer. Because of the importance placed on this study and the recent orally presented (but not published) report, and the requircments outlined above for the scientific basis of rationally promulgated occupational health standards, I undertook a visit to this plant during the week of January 12, 1976, with the hope of obtaining specific dust exposure data during the period since 1951, with the view of correlating level of exposure to asbestos dust 4 with the demonstrated mortality results. Exceptional cooperation by the medical director, industrial hygienist, and management of this plant resulted in their providing extensive exposure information for this cohort, which formed the basis for the following comments. Dust data between 1951 and I960 arc based on sampling using the Casclla Thermal Precipitator giving particles per milliliter, and since 1961 arc based on static or area sampling using the membrane filter method and providing fibers per milli liter. For the decade prior to 1961 (when fiber counts first became avail able), the particle counts were converted to fiber levels. Using these data, an individual exposure estimate was r econstructed for each member of the mortality cohort for the period 1951 through 197-4, using yearly average data obtained for each job site in order to provide cumulative exposure during the total work time in this plant for all of those employees entering the industry since 1951 and having ten years or more exposure. While my purpose is to summarize and highlight relevant aspects of this information, fuller exposition of the data can be obtained by requesting direct testimony from plant officials, ^possibly for the hearings to be held on this proposed standard. It should also be noted that concurrent with my receipt of these data, the identical information was supplied to Dr. John Gilson, Director of the Medical Research Council Pneumoconiosis Unit in South Wales, who is concerned with the British Occupational Hygiene Society (BOHS) standard (see below) and Professor Richard Doll of the Oxford Epidemiology Unit, the 4 author of the mortality papers. The current U. K. chrysotile-asbestos standard was published by the Department of Employment in 1970 with the permissible continuous expos ure level being 2 fibers per milliliter . For intermittent exposure up to 12 fibers per milliliter the action required by the factory inspectorate is depend ent upon the level and duration of the exposure. Exposure data from the study plant clearly indicate decreasing fiber levels during the 1960's so that in many job areas in the plant dust levels after 1970 were at or near the stand ard of 2 fibers per ml. It is fair to state that the goal of reaching this standard is being achieved in this factory. However, fiber counts between 1961 and 8 197Z reveal mean values in some job areas ranging as high as 26 fibers per ml., with standard deviations close to that number, indicating that some individual counts would have to have been many times the current standard in either country. Again, it must be emphasized that in the main these very high values were obtained prior to the 1969 asbestos regulations (U. K. ). However, in carding And several other job sites, more recent sampling data continued to show some average values of 4, 5 and 6 fibers per ml., with standard deviations around the mean again indicating individual fiber counts at higher levels. Among those individuals first exposed to asbestos dust in this I plant since 1951, ten have now been certified by the Pneumoconiosis Medical Panel as having asbestosis. The minimum exposure period of this group was 10 years, maximum 18 years, mean of 14 years; and the cumulative mean group exposure was 170 fiber-years per ml. All of these workers were men and entered the plant between 1951 and 1956. Their individual cumulative exposure calculations ranged from 66 to 280 fiber years per ml. Six individuals in the cohort first employed since 1951 have died of respiratory cancer, five of these whose time from initial exposure to death was greater than 15 years. These persons were all cigarette smokers whose year of first exposure ranged from 1952 until 1956. In each of these six individuals, the average yearly exposure to asbestos while employed exceeded 9 4 fibers per ml. Asbestosis was indicated on the death certificate in two of these six respiratory cancer deaths, but obviously this in no way indicates the absence of histologic (or radiographic) evidence of dust-related pulmonaryfibrosis in the remaining four. While the concept of a cumulative exposure calculation is probably deficient in that it ignores the residence time of fiber in the lungs and concen tration of airborne fiber, the current U. K. asbestos standard is based on the premise that a cumulative exposure of 100 fiber-years per ml. over a working lifetime constitutes an acceptable risk in terms of adverse health effects. In this regard, it should be noted that approximately one-third of the post-1951 4 cohort has had cumulative exposures exceeding this amount in what has been considerably less than a "working lifetime". Maintenance workers in this plant (and in the rest of the world) have had intermittent High exposures continuing to the present time. In this plant, this is documented by recent dust data obtained between carding machines grouped within an enclosure where ordinarily production workers are not stationed. Some of these fiber counts arc in the 20's and 30's but with mean values generally below 10 fibers per ml. Finally, the exposure analyses reveal an interesting group of 58 workers in the weaving department whose nverage exposures have usually been 2 fibers per ml. or below. Cumulative individual exposures .in this 10 sub-population have brcn below 75 fiber years per ml. in workers first exposed since 1951. It is of interest that in this population, there have been no eases of certified ashestosis or lung cancer, encouraging preliminary evidence in regard to the safety of a 2 fiber per ml. average exposure. There have been no eases of mesothelioma in the post-1951 cohort of this plant. The conclusions to be drawn from the biologic and exposure data from this asbestos textile plant since 1951 are reasonably straightforward. It is probable that an excess risk for the development of respiratory cancer exists in the post-1951 cohort being studied by the Oxford group. The numbers are small and Professor Doll indicated to me in January, 1976, that this excess has not yet been firmly established. In addition, asbestosis has appeared in members of this cohort. In this population, asbestos exposures during the past 20 or more years have on average clearly exceeded the current 2 fibers per ml. standard and these studies in no way invalidate that standard in regard to its adequacy in protecting from asbestos-related health effects. The use of this report (30) in supporting a change from a standard (2 fiber per ml. ) which has not yet become operational in the U.S. to 0. 5 fibers per ml. must be considered at best invalid and at worst misleading. Often not recognized, particularly in the U.S., is the fact that the current British asbestos standard of 2 fibers Per ml. is not based on the Doll mortality studios discussed previously. Tlic standard is the result of a recommendation by the British Occupational Hygiene Society (DOHS) publishcd in 1968 (in). Tins standard of 2 fillers per ml. for chrysotilc asbestos was suggested by the BOIIS subcommittee on asbestos after review of morbidity data provided by Dr. John Knox, medical director of this same British asbestos textile plant. While both clinical and radiographic informa tion was considered in assessing the asbestosis risk, the earliest indicator of disease (upon which the standard is based primarily) is the finding of inspiratory rales on auscultation of the lungs. This standard was reviewed by the BOILS committee and their findings published in 1973 (ZA). They concluded that no change in the standard shoidd be recommended at that I time but there should be continuing review. Approximatcly one year prior to this published review of the asbestos standard in Britain, an article authored by the current chief medical officer of this British plant, Dr. Lewinsohn, precipitated considerable controversy, primarily emanating from this side of the Atlantic (14). Jt was suggested that this "new informa tion" indicated a greater prevalence of radiographic changes of asbestosis than the previous work by Dr. Knox had documented. The arguments are complex, if not confusing, but certain points should be mentioned. The experimental classification used in determining radiological change in the Lewinsohn paper resvdts in significant differences from those published in tlic BOILS report. The interpretation of the observed radiological abnormal 12 ities with respect to their significance to asbestosis was not attempted in the Lewinsohn paper. liquating the lowest category of radiographic change with the disease, asbestosis, is obviously of questionable merit and as previously indicated, the x-ray appearance was not the primary basis for the establish ment of the BOHS standard. In view of the described dust exposure levels in this plant since 1951, the controversy concerning differences in interpreta tion of morbidity data is less relevant in assessing the safety of a Z fiber per ml. average exposure standard. The BOHS subcommittee has for the past several months been reviewing the asbestos standard in the U. K. Updated dust exposure 'data similar to those described previously are being correlated with the various in$dicators of a biologic response in exposed workers, including clinical, radiographic and physiologic information. A recent meeting of this subcommittee (mid-January, 1976) failed to result in even a preliminary position concerning the asbestos standard and it appears that it will be some months before a report to the full BOHS standards committee will be completed. It is only after the BOHS committee has approved the final report that it will become generally available. Considerable attention has also been directed toward the report of an investigation by NIOSII presented at the Conference on Occupational Carcin ogenesis, New York Academy of Sciences, in March, 1975 (41). This Study entitled "Morbidity and Mortality among Hard Rock Miners exposed to an 13 Asbcstiform Mineral", lias been cited by OSILA. in support of their proposed change in the standard for occupational exposure to asbestos. The studypurports to show that a population of miners who have been exposed to non commercial amphibolc fibers (cummingtonitc, gruncritc), in low concentra tions and with the preponderance of fibers shorter than 5 microns in length, have experienced an excess of respiratory cancer associated with this exposure. Widespread critical comment concerning this study, its design and interpretation of results, lias resulted in two major substantive revisions by the authors since the OSHA citation. Among workers having achieved a minimum of five years under * ground gold mining experience by I960, ten deaths due to malignant neo plasms of the respiratory system were observed with an expected of 2.7. Two of these tumors did not involve the lung, being classified as carcinoma of the maxillary sinus and mediastinum, locations not previously related to occupational asbestos exposure. In two additional tumors of the lung, it was not specified whether these lesions were primary or secondary in the lung. In the remaining six, a primary malignant neoplasm of the bronchus and lung was specified. The possibility must be considered that a definite excess of primary respiratory cancer in this population has not been demon strated. Perhaps of greater importance is the fact that this population has been exposed to a number of potentially carcinogenic materials. In the early drafts of their paper, it was stated that arsenic levels of 5 to 6 14 micrograms per cubic meter were measured in tins mine in 1974. Although the authors preclude the possibility that arsenic (a known carcinogenic material) may have played a role in any excess respiratory cancer risk, a NIOSH investigator added to the list of authors in the last draft presented a separate paper on inorganic arsenic at the same New York Academy of Sciences meeting in March with the following statement included in the published abstract of this report: "the only quantitative epidemiological study, reported in 1974, revealed a dose-response demonstrating an increased lung cancer mortality risk at arsenic concentrations above 1 microgram per cubic meter, calculated as the average occupational exposure over a 4Q-ycar work life". The conclusions of these NIOSH investigators in this same meeting seemed contradictory, and it is diffi cult to understand why specific reference to the arsenic levels have been deleted from the final gold mine study draft. ' Two of these same NIOSH investigators have previously pointed out the pulmonary carcinogenic effect of radon daughter exposures in the uranium mining industry (3A). Dr. Wagoner also authored a paper entitled "Unusual Cancer Mortality among a Group of Underground Metal Miners" published in the New England Journal of Medicine in 1963 showing a respira tory cancer excess of a magnitude similar to that claimed in the gold mine study (4A). No ctiologic factor was firmly established, although trace metals, 15 arsenic, and radioactivity were mentioned as possible causes for tins observed mortality experience. In a 1971 monopraph published jointly by the National Institute for Environmental Health Sciences (NIKHS) and NJOStI, reference is made to the underground hard rock mining experience reported in 1963 with the conclusion that although radon daughter exposure levels were low in 1958, previous exposures were probably significantly higher due to poorer ventilation in past years (5A). Certainly, this same explanation for significant radon daughter exposure levels in the past could also have been applied to the gold mine study but for some reason was not. It is also very curious that in none of the three drafts of the gold mine study was there reference to the 1963 metal mining publication although the current study 4 claims to show excess respiratory cancer mortality which the same author had already described in metal mining more than ten years previously. The causal factors may have been different in the two mines, but this is by no means proven. Additional confusing factors concerning the gold mine study should be noted. The initial draft contained morbidity information concerning the prevalence of radiographic changes thought to be consistent with pneumo coniosis. The final draft has dropped this aspect of the report. In the second draft of this paper, the authors state "These samples indicated an airborne silica concentration of 3.3 to 7.2 milligrams per cubic meter. 16 both of which exceed the TLV for silica". These airborne silica data arc excluded from the last draft. Tins is of partievdar interest since the .authors claim that a statistically significant excess in non-malignant respiratory disease was noted in this cohort. In the earlier draft, this excess i9 entirely explained by a diagnosis of "silicosis" in four of these miners. It would be difficult to associate the finding of silicosis at death with past expos ures to small asbestos fibers. This subject is further confused when in the last draft the term "pncumoconiotic disease" is substituted for silicosis as the cause of death in the non-malignant respiratory disease category. Smoking analysis, which was included in earlier drafts, is no longer present in the pre-publication or last draft. Additionally, the single paper which was presented orally at the conference was divided into two papers after the second draft, the additional paper now entitled "Asbestos Fiber Exposures in a Hard Rock Gold Mine". It describes the amphibole fiber measurements indicating an average concentration of 0. 36 fibers per ml. greater than 5 micron in length, and an average total fiber concentration of 4. 82 fibers per nil., with 94% of the fibers being less than 5 microns in length. The conclusions of this second paper, however, include broad statements concerning the health effects of tins exposure, none of which are supported or even dealt with in the results reported in the manuscript. 17 Jt can be appreciated from the above that there is little or no evidence presented to support an association between the fibrous dust exposure in this gold mine and an excess risk for the development of respiratory cancer in a cohort of past mining employees. These workers have been exposed to a number of potential carcinogenic agents and indeed an excess mortality risk for respiratory cancer in metal mining had prev iously been demonstrated by the NIOSH group. The exposures to these other potential inhalants, particularly radon daughters and arsenic, have been inadequately characterized in this cohort, particularly in the last draft. Information from previous drafts suggests that at least for arsenic, the exposures may have exceeded those levels suggested separately by one of the authors to be associated with an excess respiratory cancer risk. In view of these comments, it is difficult to understand OSHA's justifica tion for citing this study in support of its proposed asbestos standard change. I would like to turn now to a briefer summary of the additional "new evidence" cited by OSI1A in support of the proposed standard change. A cancer risk was again noted in a cohort of insulation workers being followed by Selikoff (16). This review is essentially an update of previously presented data but docs not relate the mortality experience with information concerning past asbestos dust exposure. As with most of the other studies available, no information upon which numerical standards of asbestos exposure can be IS based is forthcoming in this latest report presented at the International Conference on Biological Effects of Asbestos, in Lyon, France, in 1972. At this same meeting. Dr. Selikoff's group again confirmed the interaction between asbestos exposure and cigarette smoking and the risk of developing carcinoma of the lung (20). It was suggested that this risk may also extend to asbestosis but again in the absence of exposure information, it is difficult to justify the inclusion of this report in the literature purporting to support the asbestos standard change. Also made available in the recent past is a paper reporting the presence of asbestosis, lung cancer, and mesothelioma in a cohort of workers who have had past exposure in an amosite insulation manvufacturing operation (lft). It is clearly stated that "no information is available concerning dust levels in this plant" and this interesting study is hardly useful in the setting of safe asbestos standards. A study of insulation workers in Belfast, published in 1971, confirmed the New York insulation experience and found excess mortality in asbestos-exposed insulators for the specific causes of lung fibrosis, lung cancer, mesothelioma, and gastro intestinal malignancy (26). Of interest is that the lung cancer cases had associated pulmonary fibrosis (asbestosis) while those individuals who died of mesothelioma did not. This result speaks to the controversy concerning whether a she s tos-r clat ed lung cancer is associated with a level of exposure which has also resulted in pulmonary fibrosis. Again, in the absence of 19 exposure informotion, this report docs not help in the standard-setting process. A report by Entcrlino in 1972 (17) reveals that in workers engaged in the manufacture of asbestos products who have had mixed fiber exposures that maintenance men had a greater risk of developing respiratory cancer than production workers, presumably because of high intermittent exposures. It was also pointed,out that men in maintenance jobs may have had a higher crocidolitc exposure and that this type fiber may be more carcinogenic than chrysotile. That crocidolite exposure at similar total asbestos dust levels may be more hazardous in regard to the development of asbestosis was recently reported at the Fourth International Symposium on Particles and Vapors, in Edinburgh, in September, 1975 (6A). Little relevance to occupa- I tional standard setting is gleaned from these reports except that they suggest the possibility that, as in the U. K. , there should perhaps be a different occupa tional standard for crocidolite fiber than there is for chrysotile. . Three reports are cited in the OSHA proposal which draw attention to the health effects associated with past employment in dockyard and ship yard workers (35, 39, 40). No dust exposure information is available in these studies and the comments made above in regard to requirements for standard-setting apply equally to these reports. Fletcher (40) suggested that a better association existed between malignancy and pleural plaques than with pulmonary fibrosis. 20 A number of cited references concern themselves with tlie associa tion between asbestos exposure and the risk for the development of pleural or peritoneal mesothelioma (21, 22, 23, 25, 32, 33, 3-1, 37, 38). As no environmental dust data arc reported in any of these studies, dose-response relationships can to date not be established for these malignant tumors. Considerable crediUshould be given to Wagner (21) for recognizing and reporting this association in I960. These tumors have been reported in cases where the exposure had been occupational but also where contact had been in the household or in the vicinity of an industrial or mining asbestos source. It sho\ild be recognized, however, that these non-occupational sources of exposure arc not necessarily low but probably of tlie "intermittent high level" type, perhaps similar to those exposures exper ienced by individuals in factory maintenance jobs. In the absence of more precise information, the demonstration of these associations does not help in setting safe levels of asbestos exposure. Certainly, there is no scien tific basis for concluding that household or other non-occupational exposures have been in the range of 2 fibers per ml. or less. Ncwhousc and Berry (25) reported on a statistical model designed to predict future mesothelioma rates in a' cohort of workers previously employed in an asbestos textile factory near London. Past exposures had been admittedly high prior to the closing of the plant in 1968. Dust levels, however, were not available and this 21 interesting paper presented at the Brighton meeting in late 1075 again does not help us in setting standards. Webster (32) reported a differing risk for the development of mesothelioma in South African residents in regard to two deposits of crocidolitc asbestos (Cape and Transvaal). He suggests the possibility of an additional mineral in the Cape crocidolite area which had the higher mcsnthclioma rate but other evidence suggests that the differing structure of fibers from these two sources may prove to be the explanation for these differing biologic effects. Greenberg and Lloyd Davies (33) point out that two-thirds of their cases of mesothelioma registered by the Employment Medical Advisory Service in Britain had a recognizable past exposure to asbestos. I ' ` Two reports are cited in the proposal suggesting an association between asbestos exposure and laryngeal carcinoma (27, 28), This asso ciation, while requiring confirmation, is certainly not surprising in view of the potential for fiber deposition in the upper respiratory tract. Its relevance to the changing of an asbestos occupational standard is unclear. Edge (!?) emphasizes tho.proscnce of pleural plaques in Asbestosexposed men who ultimately developed the described health effects associated with this exposure. No quantitative environmental information is available. Anderson (15) reports radiographic abnormalities consistent with asbestosassociated effects in a group of household members of workers in the 22 amositc plant previously discussed. Both pleural and parenchymal changes were found but the association of these radiographic abnormal ities with asbestos exposure must be studied further and the x-ray readings should be confirmed. Assuming the changes to be present, the past level and intermittency of exposure in these households is completely unknown. Considerable asbestos dust must have been brought to the homes by workers returning from a factory without significant dust control, since the same New York group of investigators have recently found evidence of significant asbestos fiber accumulation in these homes up to the present time. An interesting and provocative paper presented at Brighton by Nicholson (19) reviews the factors involved in arriving at a threshold limit value (TLV), particularly the limitations of this approach. While this review or editorial provides stimulus for further scientific and philosophical discussion concerning the standard setting process, it docs not claim to present evidence supporting the proposed change in the asbestos standard to an average of 0. 5 fibers per ml. 1 agree with the statement in Dr. Nichol son's summary: "in the case of asbestos, current exposures can only be described crudely at any level of exposure, and health effects are only known for past high, but ill-defined, exposures." Finally, in another thoughtful paper cited by OSIIA, Berry (11) stresses the importance of acceptable risk as balanced by the benefits of using the particular material 23 for which the standard is being considered. He uses as an illustration the promulgation of the 1968 I301IS standard of 2 fibers per ml. (10). The remainder of the references cited in the OSHA proposal including an article hy Jane Brody in the New York Times must be considered irrelevant to the current standard setting procedure and hardly requires fur ther discussion. Finally, it seems to me that there are two major alternatives pres ently available in the setting of an occupational standard for asbestos expos ure. Tho first depends upon the premise that the adverse health effects demonstrated ;n workers have resulted from high but poorly quantitated # levels of asbestos dust. Where such information is available, doseresponse relationships have indicated that for mortality from malignant disease (7A) and for asbestosis (8A, 9A), these risks were associated with levels of exposure considerably higher than the current or proposed asbestos standards. That a working population has not had long-term exposure to even current standard levels of exposure has already been emphasized. In the absence of such' epidemiologic data, one can hardly find convincing evidence on which to base present further lowering of the asbestos standard. Nor can these non-existent data invalidate the 1976 standard of 2 fibers per ml. Because no population has been available whose working lifetime exposure hn s averaged 2 fibers per nil. , one cannot finally conclude at this time that this level is "safe" in regard to all health effects recognized to be associated with asbestos exposure, in all exposed individuals. However, it is also impossible to state that the proposed average exposure of 0. 5 fibers per ml. for a working lifetime is free of these health hazards. However, the limited information available from studies on both sides of the Atlantic, which attempt to define doseresponse r clationships, is encouraging in regard to a 2 fiber per ml. standard. The other alternative depends upon the following argument. Occu pational exposure to asbestos at some level has been shown to be associated t with a carcinogenic risk. Since a safe threshold level of exposure cannot be scientifically proven at this time, the standard must require that all exposures be at or below the lowest technologically feasible level. The implications of this approach, vis a vis the multitude of carcinogenic materials in our environment, arc far-reaching and must be faced. Those who favor this alternative must vigorously support a uniform approach and defend the resulting consequences on life in our society. I favor the first alternative as being prudent and protective of the worker's health in light of the best available current scientific information. The 2 fiber per ml. standard, which is to take effect in this country in mid-1976, has not yet become a reality in either the U.S. or U. K. This standard should be given 25 a reasonable trial while further epidemiologic investigation establishes its safety or lack of it. In conclusion, I wish to indicate that I am pleased to have had the opportunity to comment on the OSHA proposal for a new asbestos occupational exposure. In view of the importance attached to the most recent report on the British studies, I would like to emphasize and again draw attention to the new exposure information which I have sum marized earlier in this statement. It is in light of these past exposures that the biologic d.ata must be interpreted. # Re for oners References with numerals only (1-42) arc those cited in the OS I LA proposal. 1A through 9A follow: Doll, R. Mortality from lung cancer in asbestos workers, Brit. J. Indust. Med. , 12:81, 1955 BOHS Review of the hygiene standard for chrysotile asbestos dust, Ann. Occup. Ilyg. 16:7, 1973 Wagoner, J.K., Archer, V. E. , Lundin, F. E. , Iloladay, D. A. , and Lloyd, J. W. , Radiation as the cause of lung cancer among uranium miners, N.E.J.M. 273:181, 1965 Wagpner, J. K. , Miller, R. W. , Lundin, F. E. , Franmen, J. F. Haij, M. E. , Unusual cancer mortality among a group of. underground metal miners, N. E. J. M. 269:284, 1963 4 and Lundin, F. E. , Wagoner, J. K. , and Archer, V.E., Radon daughter exposure and respiratory cancer; quantitative and temporal aspects, NIOSH and N1LHS Joint Monograph No. 1, 1971 Weill, H. , Rossitcr, C. E. , Waggcnspack, C. , Jones, R. N. and Ziskind, M. M, : Differences in lung effects resulting from chrysotile and crocidolitc exposure. Fourth International Symposium on Inhaled Particles and Vapours, In press, 1975 McDonald, J. C. , McDonald, A. D. , Gibbs, G. W. , Siemiatycki, J. and Rossitcr, C. E. , Mortality in the chrysotile asbestos mines .and mills of Quebec, Arch. Environ. Health, 22:677, 1971 Weill, II., Rossitcr, C. , Ziskind, M. , Waggcnspack, C. : Lung function consequence of exposure in asbestos cement products manufacturing plants. Arch, of Environ. Health, 30:88-97, 1975 Weill, H. , waggcnspack, C. , Rossitcr, C. , Bailey, W., Ziskind, M. Radiographic and physiologic patterns among workers engaged in the manufacture of asbestos cement products: a preliminary report. J. of Occupational Med., 15:248, 1973. CURRICULUM VITAE I Ians Weill, M. I). Education Tulane University, 1051-54, B.A., June, 1955 Tulane Universi ty School of Medicine, 1D54-5B, M. D. , June, 1958 Post-Graduate Medical Training ' Intern, Mt. Sinai Hospital, New York City, 1958-59 Resident, Chari ty Hospi tal of Louisiana, New Orleans, Tulane Medical Unit, . 1959-GO * Research Fellow, Department of Medicine and Pulmonary Laboratory, Tulane University School of Medicine, 1960-61 Chief Resident, Charity Hospital of Louisiana, New Orleans, Tulane Medical Unit, 1961-62 Teaching and Research Appointments Instructor in Medicine, Pulmonary Diseases Section and Pulmonary Laboratory, Tulane University School of Medicine, 1962-64 Assistant Professor of Medicine, Tulane University School of Medicine, " 1964-67 Associate Professor of Medicine, Tulane University School of Medicine, ' 1967-71 Professor of Medicine, Tulane University School of Medicine, 1971-present Director, Specialized Center of Research (SCOR) in Occupational Respiratory Disease, NHLI, 1972- Hospital Appointments Visiting Physician, Charity Hospital of Louisiana at New Orleans, Tulane Unit Chief, Pul/nonary f unction Laboratory, Veterans Administration Hospital, ' New Orleans, 1083-present Consultant in Pulmonary Diseases and Medicine, USPHS Hospital, New Orleans, 1964-present I Hans Weill, M. D. - CV cont'd Honor!! and Societies Phi Beta Kappa, 1 9 S5 Alpha Omega. Alpha, 1958 American Thoracic Society, 1962 Orleans Parish Medical Society, 1963 Diplomatc, American Board of Internal Medicine, 1965 _ Fellow, American College of Chest Physicians, 1965; Governor for La. , 1970 Fellow, American College of Physicians. 1967 ' Certified in Pol -'vn !)i ?u s o s, American Board of Infernal Medicine, American Federation for CUnical Ftrscarch, 1967 Southern Society for Clinical Investigation, 1969 Chairman, Post-Graduate Course, Pulmonary Function in Health and Disease, 1970-72 Fellow, Royal Society of Medicine, 1971 1966 New York Academy of Sciences, 1971 Society for Occupational and Environmental Health, 1972 Councilor-at-large, American Thoracic Society, 1973 - President-elect, Amcricart Thoracic Society, 1975 Consultan"t and C"" "om>---m---i-t--t-e- e" As' sig" nments Member, Task Force on Environmental Lung Diseases, National Heart and Lung Institute, NIH, 1972 ' Consultant, National Institute of Occupational Safety and Health, TDI Criteria Document, 1973, Phosgene Criteria Document, 1975 Planning Committee, Occupational Lung Disease post-graduate course. Annual Meeting of American Thoracic Society, 1973 - Program Committee, American Lung Association, 1973 Fa cul ty Ad ui so: y Committee, Tulane University School of Medicine, 1973 - Secretary-Treasurer, New Orleans Academy of Internal Medicine, 1973 -