Document dYJ3O5O1DjMjOv6NqV3OB65v5

22682 Federal Register / Vol. 51, No. 119 / Friday, June 20, 1986 / Rules and Regulations API,. 448 U.S. at 855]. Because OSHA has efforts are concentrated on perfecting 144). These employers, therefore, would found the 0.2 f/cc level technologically the more reliable engineering and work be required hot only to measure total . feasible the Agency designated the. . . practice controls to control down to the asbestos fiber levels, but also to lower proposed limit as the new PEL. PEL rather than deflecting such efforts measure and analyze by fiber type. The Thenext point made by proponents of by requiring widespread respirator iise. difficulties in making these distinctions a 0.5 f/cc PEL Is that a sizeable portion OSHA also notes that the requirement in a timely manner as well as the of the excess risk of asbestos-related that some protective activities be uncertain capability of the reference disease is caused by smoking and instituted below the.0.2 f/cc level at the sampling and analytic method to should be deducted from the projected action level of 0.1 f/cc, is expected to reliably distinguish fiber types would asbestos risk. Accordingly, it is stated, a result in reductions in exposure for make fiber type differentials infeasible 0.5 level will more than adequately employees exposed between 0.1 and 0.2 to comply with for many industries (Tr. protect employees from the resulting f/cc. 6/21. p. 84; Exs. 90-173, 90-181 j. pure asbestos excess risk (Ex. 326, p. I- Another issue discussed in the As stated above, the health evidence 26). OSHA does not agree. As stated proposal was the need to promulgate concerning fiber differential, suggests, more fully in the section on significant different PEL'S for different types of but does not compel setting a lower PEL of risk (Section VI), the available asbestos fibers. As discussed in Section for crocidolite exposures. However, evidence shows no causal relationship between mesothelioma and gastrointestinal cancer and smoking. The evidence on the relationship between asbestosis and smoking is limited. Lung cancer risk is Influenced by smoking, but both non-smoking and smoking asbestos workers have the. samerelative lung cancer risk, compared to non asbestos-exposed workers. OSHA also believes that the IV (Health Effects), epidemiologic data suggest that exposure to amphiboles, particularly crocidolite, is associated with a higher risk of mortality from mesothelioma than is exposure to chrysotile. The United Kingdom and the Province of Ontario have both promulgated lower PEL'S for crocidolite than for other types of asbestos minerals, based on these data (Exs. 84379,-84-223). OSHA believes the difficulties of routinely distinguishing by fiber type, the fact that the dominant exposure potential is expected to be to chrysotile and the weakness of the evidence concerning fiber type, all support OSHA's decision to set a single PEI. based primarily on feasibility considerations for all fiber types. Ceiling Limit Agency's mandate under the Act Comments that OSHA received on requires that OSHA protect the: smoking this issue recommended against the worker as well as the non-smoking promulgation of different PEL's for the worker. Therefore OSHA believes that different forms of asbestos. For its risk estimates, which included excess example, NIOSH (Tr. 6/21), ORC (Ex. risk for smoking workers properly are 123-A), and AIA/NA (Ex. 328) did not the basis for OSHA's determinations of believe that the scientific evidence when excess asbestos:related risk is no. warranted Hub approach. OSHA agrees longer significant with this assessment of the evidence. Other participants urged OSHA to Although a differential risk by fiber type choose a PEL less than 0.2 f/cc. They for mesothelioma is suggested by the based their recommendations mainly on human studies, no differential risk is what levels are. technologically feasible. evident for lung cancer. In addition, For'example, the AFL-CIO urged that animal inhalation and injection studies OSHA choose 0.1 f/cc as the PEL . suggest that chrysotile, and not the because'it is the lowest level feasible to amphiboles, pose the greatest hazard. achieve. However, as discussed in the As discussed in Section IV. a number of section on technological feasibility, mechanisms have been proposed to . OSHA projected that if a. 0.1 f/cc level explain these human and animal results. were chosen, in a large number of OSHA has found that these results and operations most workers would have to the scientific community's current level wear respirators to be in compliance . of understanding of the mechanisms (See Section VII). .. leading to asbestos-related disease are Although OSHA expects that a insufficient to justify the establishment modest level of technological of different PEL's for the different development for. asbestos control and an asbestos minerals. Accordingly, in the improvement in the application.of the revised rule, the Agency has retained effectiveness of currently available best the concept of the existing asbestos. controls will occur, OSHA does not find,' . standard'that one PEL be established for on this record, evidence of a possible all types of asbestos minerals. technological breakthrough which would An additional reason to set'a single render the 6.1 f/cc level technologically PEL for all fiber types is OSHA's finding feasible in most operations. that it would be highly impractical to This final standard does not designate a ceiling limit for exposure to asbestos. This differs from the April proposal which would have retained the previous requirement in the standard of a ceiling limit of 10 f/cc to be met through engineering and work practice controls (49 FR14123). Although the existing standard's ceiling limit of 10 f/cc did not include a time period, OSHA had administratively interpreted this provision as prescribing 10 f/.cc over a 15 minute period; OSHA's decision not to designate a ceiling limit in the regulatory text is based on several considerations. First it is noted that the sizeable reduction in the time weighted average PEL affected by this revision i.e., from 2.0 f/cc to 0.2 f/cc, effectively reduces the de facto ceiling limit from the 10 f/cc level to 6.4 f/cc. This figure results from multiplying the new PEL of 0.2 f/cc by 32, the number of 15 minute periods in a workday. Therefore should an employer expose an employee-above 6:4 f/cc for over 15 minutes, he will be violating the 0.2 f/cc "TWA PEL, even if that employee has no asbestos exposure for.the remainder of that day. Similarly a 15 minute excursion over . 3.2 f/cc would constitute a time Further, this rulemaking has again require employers to distinguish among weighted average exposure over the pointed out the inherent limitations of fiber types in their measurement action level of 0.1 f/cc and would reliance on respirators to meet the PEL, programs. Most exposures jn working require the employer to institute particularly for full shift use.'OSHA with new asbestos materials are to monitoring, medical surveillance and believes that where, as here, the. . . . chrysotile, although crocidolite may also training programs. OSHA believes marginal reduction in exposure levels be present in smaller quantities (Tr. 7/9, therefore, that even without designating would.be quite small, i.e. 0.2 f/cc vs. 0.1 p. 259-280). Removal, repair and a specific ceiling level this standard f/cc, employee protection will be more abatement activities often involve effectively protects employees against reliable if employer resources and mixed fiber exposures (Tr. 6/19, p. I- short term very high exposures. GLEASON-000930