Document vBYN5p8L4qoXVGYRp613jjO5Y

M-OG9? received * UNION X * CARBIDE * k kk INTERNAL CORRESPONDENCE OCT 2 8 1986 M. A. PATEL South Charleston Technical Center Engineering Department Post Office Box 8361 South Charleston, WV 25303 DATE: TO: COPY: SUBJECT: October 24, 1986 See Attached Distribution See Attached Distribution Asbestos Sampling and Analytical Methdd OSHA, in their recently promulgated asbestos standard, specified a mandatory Reference Method for the sampling and analysis of asbestos. Although this method is very similar to the NIOSH 7400 method, there are some important differences. After comparing these two methods, the following observations were made. 1) Counting Rules. NIOSH provides two sets of counting rules, A Rules and B Rules. OSHA requires that only the A Rules be used. Their rationale for this is (i) the A Rules have already been upheld in numerous court decisions, and (ii) changing to the B Rules would be inconsistent with the epidemiology upon which the standard was based. (X .. jf > ' y.,':* 2) Differential Counting. Method 7400 makes no attempt to do differential counting. That is, all fibers are to be counted even if it is obvious that the fiber is non-asbestos. The OSHA method also states that al1 particles with an aspect ratio of 3:1 . ,\CV or greater should be counted. However, OSHA's Salt Lake City -2 Analytical Laboratory is not following this apparent requirement. A number of other sources also claim to be doing differential counting. Some UCC locations are excluding obvious non-asbestos fibers, others are not. There are positive and negative factors with both approaches. In either case our counting procedures need to be made consistent. Your comments on this issue would be appreciated. TTvtv*- ho yen* C&~- ct'Wvu-_|Lf<5-fe. rY\xV\ <3-o-`b--s4-*o ^ I/O'.'<Trf ~ \L* CLer\xv-J OWf ,3 V-> V^0 kAaa. IaJL C-O-IAV^ UCC 011239 * ^I I