Document zQRr6nBR9OOj14or98y161y37

To: Dave Penney F rom: Joe Ledvina Date: July 13, 1990 Subject: VCM Risk Factors Dave, So far I've gotten three responses to my request to the Vinyl Institute concerning the VCM unit risk factor. Joe King of Occidental sent along the Pennsylvania Air Toxic Guideline where they use 2.4 ppb as a fenceline standard. That is 1/420 of the PEL. I believe the PEL for VCM is 1 ppm. If I did my math correctly, 2.4 ppb equals approximate1y 10 ug/nr (MW/24.45 * 2.4). Apparently, in Pennsylvania if fenceline concentration is less than lOug/rrr the facility is considered an acceptable air toxic risk. The use of PEL for carcinogens seems to be the old way of assessing risk . Both EPA and the State of California are using unit risk factors rather than fractions of the PEL to assess risk. Bob Oubre also uses assessing proximity basis. of Dow - Freeport called to say that the 10 ug/rrr for VCM as an annual fenceline air toxic impact. He said that Texas to residents and allow a higher number on State of Texas allowable when will consider a case*"by--case Frank Borrelli of Georgia-Gulf in Delaware City, DE provided excerpts from EPA documents that show the VCM unit risk factor as 4.1 x 10 . A footnote states that oral studies suggest a unit risk factor of 4.2 x 10 . This is the factor Mississippi is using. If the Mississippi factor is based on oral studies, can we argue that it is inappropriate since the route of exposure is not oral but inhalation? This may allow us to argue for 4.1 x 10"*. Is there some-way you can check this out? I'll pass along any other information I get through the Vinyl Institute. vxna cc: TGG, FGJ VAB.0001165173