Document 6RvO86E0kkBXjxgQyMdM25Kp9

Federal Register / Vo!., 51, No. 119 / Friday, June 20. 1986 / Rules and Regulations 22689' (he "Asbestos Round Robin" for certified variability derived from the Chase aiid number of reasons. First, Serocki and his laboratories' sponsored -by the NIOSH. Proficiency Analytical Testing (PAT) .. program. (Ex. 330) ! Rhodes study. Furthermore, as discussed colleagues did not claim.that above, interpretation of the Chase arid electrostatic charge was responsible for Rhodes study with regard to intrinsic the differences in results between paired The NIOSH PAT program has been in error in the NIOSH PaCAM 239 method samples collected at low (21pm) flow existence for.13 years. Recently, is complicated by a lack of adequate rates: in fact, these authors concluded however, NIOSH has transferred the quality control procedures in many of that differences in results between administration of the program to the the participating laboratories. paired low flow rate samples were not American Industrial Hygiene The AIA relied more heavily on a statistically significant. Serocki et al. did Association, which will provide'PAT study conducted by Serocki et al. (Ex. observe significant differences between samples to private laboratories. Since 84-478). in which 15 paired asbestos members of paired samples where one the direction and administration of the samples placed in "close proximity" to sample was collected at a high flow rate PAT program is undergoing changes,. each other were collected in two (7,5 Ipm), and the other was collected at OSHA has not at this time required worksites where asbestos is present. a low flow rate (2 1pm), and these employers to utilize laboratories that are The sample pairs were collected at 2 authors attributed these differences, in participating in the PAT program. Ipm for sampling durations of from 25 to part, to excess electrostatic charge. Intersample Variability The third type of asbestos monitoring variability discussed by the AIA was that of intersample.variability, defined as the difference in results obtained by analyzing two samples that are taken side-by-side. The AIA cited two reports that ". . . address directly the magnitude of (intcrsample variability! ... for airborne asbestos monitoring" (Ex. 326. p. A-18). In one of these reports (Exs. 93-16. Tab D, 232-B). Dr. Chntfield useil the data from the Chase and Rhodes study to compute a CV for intcrsample variability of 0.47 for a 100 fiber count. The AIA concluded that 96 minutes. The AIA determined the CV for each sample pair and found that the average CV for intersample variability in this study was 0.62 (Ex. 328, p. A-20). The AIA asserted that electrostatic capture of asbestos.fibers on the filter cassette was at least partially responsible for the inter9ample variability observed in the Serocki et nl. report. The AIA concluded from the Chase and Rhodes and Serocki et al. studies that the CV for intersample variability for Ihe P&CAM method lies between 0.4 and 0.5 (Ex. 328, p. A-22). OSHA does not agree with the AlA's analysis of the Serocki et al. data, for a OSHA believes that some of the variability in the Serocki report's low flow rate paired samples can be attributed to the short sampling times used and the resultant low fiber counts. Table 31 9hows OSllA's calculation of the number of fibers counted for each of the 15 paired samples used by the AIA in their analysis of the Serocki data, along with the CV obtained by the AIA for each sample pair. This table shows that, for the vast majority or samples analyzed by Serocki et al. (Ex. 84-478). total fiber counts were below the minimum of 80 fibers recommended by the NIOSH 7400 method (Ex. 84-444). . . the breadth of the Chase and Rhodes Study warrants considerable weight Tor this evidence" (Ex. 328, p. A-19). Table 31.--Number of Fibers Counted Per 100 Fields ano Coefficients of Variation Reported by AIA for Each of 15 Paired asbestos Sampixs Reported by Serocki et al. [Ex 64-476) Yehia Hammad, D.Sc.. Associate Professor at the School of Medicine. Tulane University, commented on this estimate of intersample variability Sample No.` ` Concentration (f/cc) No. Of fibers count* ed (100. fields) Concentration (f/cc) NO. Of ffcers count* ed (100 fields) Coefficient, of variation reported by AIA/NA 1 under cross-examination by Tim Hardy of the AIA: I just could not see a measurement where 1 would have 47 percent variability between two points ... If we have 47 percent variability between two points, then all the , numbers that we are talking ubout today should rail out the window. Thnt means that engineers cannot go and measure anything side-by-side because the variability is-47 percent. (Tr. 6/20, p. 89) Under questioning by Mr. Schneider of 2.......... .........................--....................... .....................- .n ................................. ................... .................. ................ ..... ................ 5.;........... ..............................,,__________________ ____ _ R .......... 7 .................... ............ .............. 8........ .;.............................................. ;............... ................... g ....................;......... ....................... .... ...... ..... ................. . 10.............. ....... .... .... ............... .............................-........... 1\....... ...................... ....... ........................ . ................ . 12.......................................... --r........ ... ............. .............. 13.................................................. ................. -................. . t4 .................................................. ......... 15 - - - ---------- -- 0.40 .35 .17 1.0 .78 .32 N0<01-.16) * ND(DL,09) NDIDL~.07) ND(DL=..14> 3.37 .24 7.26 7.90 .15 17 30 te 29 36 23 to to 10 10 236 17 594 444 17 1.1 .61 ' .47 *ND(DL=.34) .51 .42 J0Q .26 .21 .56 2.96 J6 .7.79 9.01 .14 46 44 51 10 24 30 54 30 29 39 208 - 26 . 638 506 16 . 0.66 .26 .66 1.33 .28 .19 1.37 1.32 1.35 1.34 .09 .28 .05 .09 .05 the BCTD, Dr. Hammad elaborated on the cause of intcrsample variability; . * Ex. 328. Appendix A. p. A-20. * NONot Detected; OSHA determined minimum detection fovot (DU assuming a fiber count of 10 fibers per 100 fields and a microscopic field area of 0 005 mm*. The variability that is present depends on the properties of the dust cloud . . . [I|f you are walking in a dust cloud . .'. then there is Evidence to support OSHA's of these four 8-hour TWA pairs, CV's of a difference between dust concentrations at contention about the importance of fiber 0.115, 0.88, 0.018, and 0.057 were . different points. And the point that 1 was making is that I do not see any reason, and I haven't seen during the past 15 years that I have been working in this field, that dust ' concentrations between two points four or five inches apart will be 47 percent. Things counts to the reliability of the results is found in an analysis of the CV's for four pairs of 8-hour TWA exposure levels reported by Serocki that.were calculated from paired'short-term samples taken obtained, respectively; these CV's reflect the adequate sampling times and fiber counts associated with these four samples. OSHA therefore concludes that just don't happen that way. (Tr. 6/20. p. 121) consecutively over a working day (Ex. counting an adequate number of fibers OSHA believes that-the testimony of Dr. Hammad casts considerable doubt on the estimated CV for intcrsample 84-478, pp. 11-12). (The AIA did not analyze CV's for these sample results.) When OSHA calculated CV's for each when analyzing airborne asbestos samples is of the utmost importance. Accordingly. OSHA does not agree that GLEASON-000937