Document VK2Dr7649ZEJrXo1b6XEXpQvq

W. C. Strader R. F. Cope, Jr. Asbestos - Diaphragm Preparation Sodium Operations L/ New Orleans New Orleans July 13, 1970 On July 8, 1970, air samples were taken relative to the handling of dry asbestos at the subject location. The asbestos is handled while making a slurry with which to prepare diaphragms. Slurries are pre pared on a daily basiB and the work is usually performed at the beginning of the work .shift {about 7 A.M.). The operation had already been com pleted on the day scheduled for survey of the procedure; however, several employees in the building simulated the handling of the asbestos fibers at which time air samples were taken. Two types of asbestos (long and short fiber) are handled in this operation. The dry asbestos is weighed on a scale (4 lbs. of long fiber and 54 lbs. of short fibers) attd then is dumped into a vat where a slurry is mixed. Since the actual slurry mixing involves a wet process not felt likely to be hazardous, the mixing site was not surveyed; however, the weighing and pouring of the dry fibers was examined. It takes about ten minutes to complete the weighing and pouring of the fibers into the vat. According to shop supervision, this particular job is rotated among employees and the same employee will perform this task about once every five days. Atmospheric samples were taken in the immediate area about 8:30 A.M. where the two asbestos fibers are weighed. Results of examination of the samples was as follows (all samples were taken in the breathing zone): Site of Sampling Result Before weighing the dry asbestos During weighing of the asbestos No asbestos fibers were identified invthis sample Less than 0, 1 mppef* Immediately after the weighing and pouring operation Less than 0.1 mppcf* ETH00002805 Asbestos - Diaphragm Preparation Sodium Operations Page 2 Site of Sampling Re suit Approximately 30 minutes after the weighing and pouring operation Less than 0. 1 mppcf* * mppcf - million particles per cubic foot of air. A few fibers were noted but precision of counting is not so accurate that more definite numbers should be presented. .The threshold limit value (TLV) which is presently recommended by the American Conference of Governmental Industrial Hygienist (ACGIH) for asbestos fiber dust is 2 mppcf. This value is based on a possibility of repeated exposures for 8 hour work days. Operations being performed here are .for. even-lesser periods. Our samples which were taken under simulated conditions at the operation site did not reveal amounts of asbestos dust fibers in the breathing zone that are considered hazardous according to the above criteria. RFC/mh cc: R. C. A. Bock, M. D. George Roush, M. D. Robert F. Cope, Jr. Industrial Hygienist ETH00002806