Document dnb5ze0dpjbQwgd70X1MdaaL5

FILE NAME: Visible Dust (VDT) DATE: 1976 Apr 6 DOC#: VDT024 DOCUMENT DESCRIPTION: Memo - Union Carbide i * , v. , lV M o .< , , m . /Vjs >.../ ' < * -. jhU.-Av- Mr. J. F. Ballew, Jr. Building 70-1Q8A INSTITUTE PLAST Ms, B, J, Mitchell Mr. J, G, Perkins M r . F . Williams April 6,, 1976 B.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 filter samplers worn by employees while preparing sample dishes Analytical Laboratory Room 108. The results of these samplings follows: count on in the are as Da ta 12/22/75 1/12/76 3/1/76 Employee C. W. Devers D. DeLuca J, 0, Good Fiber Count/ml Air .447..96 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 asbes tos dust exposure is currently 5 fibers greater than 5 micrometers in length per cc of air as a time weighted average (TWA) and a ceiling value not to exceed 10 fibers 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, H H F :Is /\C4 iVa/ -i/?,, .t, i`razxer w U/ j UCC 008858