Document 7MZxrVvgpw8jjKxVZq0Jje0Ge

ACCIH Aab* stos Symposium PLAINTIFF'S EXHIBIT ATT-6S Btl Laboratories April 26, 1979 Vicki R. Cohen On April 9, 1979, l at tended an ACCIH Symposium on technique* for evaluating airborne aabeacoa dual. After sosm opening remarks by David M. Trayer, Chairman ACCIH, the objective* of the program were ditcuaaed by Jame* S. Ferguson of NIOSH, the program chairman. The progrms aime^were to discuss the following: (1) Identification of asbestos; finding a practical, cost-effective technique. (2) The NIOSH method, an evaluation not identification technique. (3) Methods of analysis now in use. (A) Asbestos in schools (5) Insulators in industry, hair dryers, etc. Speaker* scheduled to *peak in the morning included Halter C. MeCrone, McCroq* Research Inst., Dr. Voelker A. Mohaen and Mr. Roger Cheng S.U.N.Y., Dr. Eric Steel, N.B.S., Willard Dixon, OSHA, Ian Stewart, MeCrone, and Steven 3ayer and Dick Coupell, MIOSH. Walcer MeCrone spoke about optical techniques. He claimed that the MIOSH procedure i* good, but must be refined so as to discriminate between" asbestos and other fibers. He discussed dispersion staining in detai l. Ian Stewart stressed the importance of crystallographic identification for distinguishing asbestos from nonasbestos material. He claimed that the SEM^is not able to detect fibers less chan 300A0 in width. Eric Steele of the National Bureau of Standards discussed the use of the analytical electron microscope. With this technique resolution and contrast as well as identification of serpentine from msphibole varieties may be accomplished. Small fiber morphology nay be seen using selected area x-ray diffraction (SAD) as well as chemical composition using the electron diffraction pattern (EDS). Although SEM can see and identify most fibers, the polymorphs of the same serpentine mineral (ie., antiguerite, chrysotile), can noc be distinguished. SEM is also quite costly, and a standardized tech nique and practical time problems oust be resolved. LLA 000746 2 Dick Coup* 11 from HI08H baa developed spot test for identifying ssbestoe bulk. The tut is actually a tcraao for tha presence of magnesium. To dace, there have baaa oo falaa negatives fro* 130 aa^laa testsd. A copy of thia relatively aiaple screening caac ia attached. Hillard Dixon, OSBA Analytical Lab, apoke about quick tests which could ba don* in th* field to readily identify whether snbestos ia preaent. Some excap lea he gave were that fiberglsss aelta and makes a crinkling noiae. fiberglass ia alao easier to grind with aortar and peatle than aabeetoa. Voalker Mohnen's aain topic of diacuaaioo was the i^ortaoce of describing tha relationship between the nasa of asbestos dust to the fibers present. He stressed that an adequate fiber site distribution relating particle site to aaaa ia of great importance when determining health effects fros exposure to airborne fibera. An EPA round robin experiment was conducted in which seven well known laboratories were given the task of analysing the ease air filter senple. Each of the laboratories case up with different results. Kohnen stressed that some aeana of standardising asbestos fiber detersinations was necessary. If these highly reputable labs showed such diaagreement, what kinds of results can w* expect fros other labs lacking in their expertise. A panel discussion with the various speakers was held in the afternoon, chaired by Beajaadn Levadie, State of Vermont. He began the discus sion by asking for an honest definition of aa bee toe. He also asked Che audience to consider which forms of asbestos were nose hazardous, serpentine or smphibole. Although ampbibol* is known to be very hasardous, this vsriety colitises only 5X of the eebeatos which is used. The serpentine variety whose health effects are not entirely understood comprises 93Z of the asbestos which is used. Questions then came from the floor concerning the rational for the current aspect ratio used for fiber counting. A suggestion was that all physiologically active fibers ought to be regulated. Each panel aenber was then asked to cowent on which analytical technique is best and how it should be standardised. McCrone coamented that th* problems are not with the methods, but with the analysts. He claimed that an optical crystallographic method was the only way to determine the crystallographic nineralogic species. V Mohnen didn't reconsMod any technique and wished to leave the standard ization of methods to Willard Dixoa. Dixon made the recoMendation that standard asbestos fibers for calibration purposes be aeoe available through NBS. He suggested field by field instruction and analysis during counting procedures to standardize the N10SH method and to employ dispersion staining techniques to verify the crystallographic structure. Ia Severe spokt about standardising technique* for crystallographic identification using the electron vdcroacopa. Stevsn Bayer, who run* eh* R10SH course in phase contest aicroacopy elsined that he ha* been training individuals to count asbestos in a unifora wanner since 1971. Whether or not this asthod is best, he has standardised it to the best of hi* ability. Jia Ferguson's coaeat was Chat one technique can not be used for all purposes. The technique to be used should be dependent upon the type of saaple to be analysed. No standardised or best asthod for the identification and evaluation of airborne asbestos was decided upon at this tyupoeita. Ml the aethode discussed hed various drawbacks including Ciaa, cote, accuracy, and raprodueibility. Sevaral of ha attendaea I spoke with, however, aentioned that they would ba taking Cha McCrone course in dispersion stsining. In smeary, tha syaposiua was inforaative both in terw of the discuaaions of tha various techniques available for asbestos iden tification as wall as tha problems associated with those techniques. However, those problea* were not resolved. MH-7M3-VRC-rlh Att. K* Ust Copy_to (w/att) R. L. Beach - AT$T N. J. OeCapua J. M. Degen R. W. Stone, M.D. R. Deitchnan - BTL D. G. Hodgkins W. J. Schreibeis G. M. Wilkening N. Wood - NYT V Vicki B. Cohen