Document k6mRmeq1ne8bK3G75Jy7wQGQn

bee: T. L. Oosaage/D. B. Roush R. A. Garcia - 1010 J. A. Heilala - Pittsburgh August 1971 Mr. Tad Soanga Alcoa New Kensington, Pa. 13230 Dear Mr. Scangai Thla will confine your telephone conversation with our Mr. J hn Heilala regarding conversion of your heat transfer system from Thereinol PR to Thensinol 55, We are pleased that you are agreeable to Making this change as quickly as possible. As Indicated in previous correspondence dated June 8, 1970 Thensinol PR is a polychlorinated biphenyl (PCB) and articles have been publlahed indicating that PCBa have been discovered at some points in the marine, aquatic and wildlife environments. This ohemioal is a long-lasting, stable material and its ultimate effect in the environment is not known. During the past year the PDA hae posted guide lines of 5 ppm in food products and 0.2 ppm In dairy products. Because alternate non-PCB heat transfer fluids are available we have taken measures to eonvert all Thensinol PR users where even the remotest possibility of food contamination exists to matsrials suoh as Thensinol 53 or Therminol 66. In your esse we recommend Therminol 55* You should drain the Thensinol PR from your system as boroughly ss possible -- whieh means removing essentially all of the PR fluid. You can than add the Thensinol 35 end resume system operation. Some new Therminol 55 could be used as s flushing agent to remove any residual PR left in the system. This flush ing material should also be drained and returned for disposal. We would like to remind you that Therminol 55 is not claaaifisd as a fire resistance heat transfer fluid. Consequently, you may wish to consider the use of protective devices to minimise any added fire risks. We suggest that you oonault with the insurer of your property relative to thla natter. DSH 018327 STLCOPCB4004871 Also enclosed are labels to be plaoed on the containers of drained PR fluid for return to the address shown. We will pay the return freight. Should you have any sealed containers of new Therminol PR they can be returned for full credit but please nark the drums clearly - "for return credit". Tour cooperation is appreciated. Sincerely. os Enclosures J. J. Roder Product Supervisor Heat Transfer Fluids DSW 018328 STLCOPCB4004872