Document rexb11BX5rZzj0r1XBwdVJjRE

dona on sita In addition to sample collection. The above data do show fluctuations, but none are extreme, and it i3 apparent that the averages are reasonably representative of actual 8 houj time weighted exposure levels. The short terra method of samp ling is necessary when airborne particulate concentrations are elevated. Prolonged sampling at some locations overloads the filter, preventing accurate identification and sizing of fibers during microscopic examination. When this happens, erroneous fiber levels of from 10 to 100 times below actual concentrations may be reported. As indicated in Appendix No. 1, book and blok preform samples continued to show elevated fiber levels, especially when re lated to the 2 fiber limit schedulod for adoption by OSHA in July. Since ventilation changes have not resulted in notice able reduction from levels of December 16-20, 1574, it is . apparent that sources, or points of major dust release at each blok and book preform unit have not been adequately ventilated. Most past survey reports have stressed the need for proper exhaust enclosure of the mix buggies and hand transfer portions of the processes. This need is again reiterated. It is our understanding that engineering controls are to be installed at the mix buggy locations in Blok Preform in the near future. These plans should also include Book Preform where hooding installations have helped to reduce scattering and spillage, but have had moderate effect cn airborne fiber concentrations. A recent Industrial Hygiene Eurvey at Salisbury-PPG has dis closed preform fiber levels ranging from 0.5 to 1.5 fibers/ml. One or two locations were above 2 fibers/ml, but the reasons for the excursions were easily pinpointed and were attributable solely to poor work practices. The mix buggies and weigh scales are provided with exhaust ventilation at the Salisbury plant which appears to be containing effectively airborne asbestos levels, at least to the 2 fiber level. It is suggcstcc that FPG-hTincbester inspect tbs mix buggy enclosures at Salisbury and consider- adopting some cr all of their principles of asbestos containment. There appears to be no clear pattern of asbestos exposure as it relates to the type of mix being used at the individual work station. careless work habits and/or excessive scatter ing of the nix can be assumed to be a factor, but there are no pronounced variations except for airborne lead levels within the survey data to support this contention. The operator at blok preform No, 5 was selected for sampling because of the