Document GzXz59qVOQDjNqvyVbKOYr2Vm

> Ur.r*.^ - i*-1* in trnrnm '" -- jr*a *. 717 - AMOCVIV o. NOSCT. VWa Rwwwew mi OmumitUnit Utm* 4 NmMi U. &. Mrtk *--tm^twnv m HOWARD 1. ATlft. Vto OakwH ilw of OwAadwil blv 4 WnW> UIR.I4Vr HmM" W vWe Tel. SU -1 AMBUCAN CONFERENCE of" GOVERNMENTAL INDUSTRIAL HYGIENISTS Mr. Richard Henderson Manager, Environmental Hygiene Service* Olln Reaearch Center 275 Winch**ter Avenue Hew Haven, Connecticut 06504 im-M ' NmW f.UaiU*MnUl aOVmMMttQfaMaAWM JL ttNCM 1 4>***--` .% "OM. himi Tw__ _ April 6, 1970 APRl9ma lent week with 7. K- Rowe present and final deel*ion for a 200 ppm. This,' as you will note, was the essential er at the Gordon Conference in 1966. Apparently, Dow hasn't seen any new evidence to alter this tentative rec< ndatlon. HZST01QNGER:em Tours sincerely. fer Herbert''s. S0atoklnger, Fh.D. Chairman Threshold Limit* Committee 2 DEPOSITION 1 EXHIBIT I i /cp 3077 011-1970-00004093 OLI 1560 7INTL CHLORIDE* VC\ 50 ppa (Approximately 130 mg/w?) t Vinyl chloride is a gas of relatively low cysttalc tox icity. Torkelson, Oyen and Rowe found that repeated seven- hour axposuras at 200 ppm caused liver pathology in rabbits (1). Other investigators however report no evidence of Injury at this level. At 100 ppm slight increases in the average weight of rat livers were noted. Other animals were unaffected by 100 ppm. On the basis of these findings, the above authors^ suggested a threshold limit of 50 ppa. Subsequent human ex- - v-. *' : posure experience indicates a considerable factor of safety . for intermittent exposures during the S-hour day, and a good safety factor for the 6-hour daily exposure. The Soviet limit is 12 ppm (2). The TL7 of 50 ppm, with the provisions noted above, is recommended to protect against irritation and narcosis. References: 1. Torkelson. T. R., Oyen, F., Rowe, V. K.: A.I.H.A. J. 22, 354 (1961). "~ 2. Smelyanskly, Z. B., Ulanova, I. P., Labor Hygiene and Occupational Diseases-* Moscow, p. 7, (195L9). >Tbf NiufckU**UH DEPOSITION exhibit _/0 - 3><g? - 9-r 011-1970-00004084 innniiifliiiuiiDaDiiBBinaiinnnB 0LI 1559 Vinyl chloride chronology Page 2 In 1961, The Dow Chemical Company reported that long-term (4$ to 6 months at what would correspond to normal working hours) VCM exposures of animals to down to 100 ppm VCM resulted in slight liver injuries, and recommended working exposure levels be reduced to 50 ppm. This recommendation for worker exposure was not accepted by ACGIH. In 1962, on the basis of work done at Yale University, from which the authors concluded that 500 ppm offered an adequate safety margin for human exposure to VCM, ACGIH published 500 ppm as the recommended standard. In 1971, the Occupational Safety and Health Administration (0SHA) established 500 ppm VCM as a national standard. This changed in April 1974 when 0SHA, following voluntary disclosure by The B. F. Goodrich Company of liver cancer deaths possibly related to vinyl chloride exposure, set a temporary emergency standard at 50 ppm. Then, on May 10, citing the findings of an MCA-administered study that showed liver cancer in mice at 50 ppm, OSHA proposed a "no detectable'' ^standard, as previously recommended by the National Institute of Occupational Safety and Health (NI0SH). The following is a brief chronology of vinyl chloride activities relating to worker health. It is based on MCA records and input from U. S. producers of VCM and/or PVC. 002-1974-00000400 MIMmiMMWII (more)