Regulations (Preambles to Final Rules) - Table of Contents Regulations (Preambles to Final Rules) - Table of Contents
• Record Type: Occupational Exposure to Asbestos, Tremolite, Anthophyllite and Actinolite [1988]
• Section: 6
• Title: Section 6 - VI. The Process for Promulgating the Excursion Limit

VI. THE PROCESS FOR PROMULGATING THE EXCURSION LIMIT

As the foregoing discussion indicates, the Public Citizen Court explicitly rejected OSHA's reliance in the EtO standard on the need for a "dose-rate effect" to justify an excursion limit. OSHA based its determination in the revised asbestos standards on the same rationale. The Agency hereby withdraws the determination. Instead, OSHA has made a new determination based on appropriate criteria and a review of the rulemaking record concerning whether and what excursion limit should be required in the revised asbestos standards.

Table X shows the results of OSHA's analysis.

 TABLE X-RELIABLE QUANTITATION LIMITS FOR SHORT-TERM
 ASBESTOS SAMPLING USING THE OSHA REFERENCE METHOD

          [fiber density of 100 f/mm(2)]

__________________________________________________
                   |            |
     Flow rate     |  Sampling  |  Lower limit of
    (liters/min)   |    time    |  quantification
                   |            |    (fibers/cc)
___________________|____________|_________________
                   |            |
For 25 mm filters: |            |
                   |            |
     2.5           |       15   |         1.05
                   |            |
     2.0           |       15   |         1.31
                   |            |
     1.6           |       15   |         1.63
                   |            |
     1.0           |       15   |         2.61
                   |            |
     0.5           |       15   |         5.23
                   |            |
     2.5           |       30   |          .51
                   |            |
     2.0           |       30   |          .65
                   |            |
     1.6           |       30   |          .82
                   |            |
     1.0           |       30   |         1.31
                   |            |
     0.5           |       30   |         2.61
                   |            |
For 37 mm filters: |            |

     2.5           |       15   |         2.32
                   |            |
     2.0           |       15   |         2.91
                   |            |
     1.6           |       15   |         3.63
                   |            |
     1.0           |       15   |         5.81
                   |            |
     2.5           |       30   |         1.16
                   |            |
     2.0           |       30   |         1.45
                   |            |
     1.6           |       30   |         1.82
                   |            |
     1.0           |       30   |         2.91
                   |            |
___________________|____________|________________


OSHA's previous STEL determination did not apply the criteria which the Court held must compel the issuance of a short term limit. However, these criteria; feasibility of the limit and further reduction of significant risk were raised by OSHA in its proposal (see 49 FR 14116, 14122), and were the subjects of data and comment submitted to the record as well as testimony at the hearing. Therefore all aspects of OSHA's statutory rulemaking requirements, consisting of notice, comment and hearing, have been compiled with concerning whether OSHA must issue an excursion limit (See section 6(b) of the Act).

Ample notice on all relevant issues was provided by OSHA. In its proposal the Agency stated it was considering reducing the prior "ceiling limit" of 10 f/cc to a limit based, in large part on the TWA-PEL which would be required. OSHA specifically mentioned the possibility of imposing a 5 f/cc limit measured over 15 minutes if a 0.5 f/cc TWA-PEL were chosen and a 2 f/cc "ceiling limit" if a 0.2 f/cc limit were chosen, and requested comments on these as well as "other suggested limits". OSHA noted that ceiling limits "may be necessary to ensure further that employees are not exposed to dangerous concentrations(s) of asbestos fibers" and also asked for "(i)nformation concerning the feasibility of achieving (the limits mentioned or others) particularly in industries with variable exposures" (49 FR at 14123).

Comment and evidence submitted to the record responded to all relevant issues and provided an ample evidentiary base for OSHA to make determinations regarding a revised excursion limit for asbestos exposure. Participants representing both industry and employee groups recommended that OSHA adopt a "short term limit ranging from 0.5 f/cc measured over 30 minutes" (BCTD, Exh. 330 at 155), to 5.0 f/cc measured over 15 minutes (AIA/NA, P.H. brief, III-45).

Data introduced during the rulemaking, as discussed previously, shows the feasibility of the limit adopted. Most data relates to service industries and construction. The relative scarcity of data for general industry was explained by AIA/NA as resulting from the fact that "at least in manufacturing plants, there are few routine operations where exposures are episodic. Consequently, the occurrence of peak exposures is generally an unexpected event such as an equipment breakdown." (AIA/NA, P.H. brief, III-44).

Data used in OSHA's risk assessment and regulatory analysis similarly show that the imposition of an excursion limit of 1 f/cc measured over 30 minutes will further reduce the significant risk remaining after a TWA exposure limit of 0.2 f/cc is achieved.

OSHA finds pursuant to 5 U.S.C. 553(b), that additional notice and comment are unnecessary. OSHA believes that additional notice of the intent to consider an excursion limit would merely duplicate the prior notice. As discussed above, public participation has already taken place during the extensive rulemaking held to develop the 1986 standards.

[53 FR 35609, Sept. 14, 1988]

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