Document pmz77XnKrV66wLN1BkMq2q427

i> 'V*-, *5, ^ A A>*D Mr. J. F, Ballew, Jr. Building 70-108A INSTITUTE PLANT Ms. B. J. Mitchell Mr. J. G. Perkins Mr. F. Williams . April 6, 1976 . E.R. - Industrial Hygiene , You have asked that measurements be made of personnel exposure to airborne asbestos fibers while weighing dishes are being prepared for resi due analyses. Our records show that a similar measurement was made in Specifications Laboratory Room 205, March 10, 1975, and was reported to be slightly above threshold limit value (TLV), Three determinations have recently been made by fiber count on filter samplers worn by employees while preparing sample dishes in the Analytical Laboratory Room 108. The results of these samplings are as follows: . bate Employee Fiber Count/ml Air 12/22/75 1/12/76 3/1/76 C. W, Devers D. DeLuca J, 0. Good 4.9 47.6 7.7 We observed each of these samplings to be similar in technique and airborne dust was not visible in either instance. The TLV for ashes- tos dust exposure is currently 5 fibers greater than 5 micrometers iii length per cc of air as a time weighted average (TWA) and a ceiling value not to exceed 10 f ibers. greater than 5 micrometers in length. As of July 1, 1976, the TLV will be reduced to 2 fibers as an OSHA allowable limit. This job task is only infrequently performed and it is unlikely that the TLV as TWA would ever be exceeded. Our measurements, however, show that the ceiling level can be excessive. We, therefore, recommend that work involving preparation of sample dishes with asbestos fibers be performed within an exhaust ventilated hood. HHF:1s S7 / ','j Jj H. H. Frazier' A 04073 UCC 008858