Document nNRy74M0yvGpkkdNB6OQp8v8a

WRG 001237 GRACE Zonolile Construction Product* Divi W R Groce & Co. P.O. Bo* 2503 2500 South Gomsey Street Somo Ano. CA 92707 (714)979-4900 March 4, 1982 Mr. Jacob Robbins FAIA Robbins and Ream Inc. Architecture/Urban Design 212 Sutter Street San Francisco, CA 94109 Dear Mr. Robbins: In connection with your February 12 letter addressed to our Newark, California office, I am writing to confirm that our spray-applied plaster formulations prior to mid-1973 contained asbestos as an ingredient. Because of the "setting" characteristic of these gypsum based products, we believe that the asbestos fibers are encapsulated in the matrix -- a conclusion that assumes that the materials have remained undisturbed and have not been subjected to physical damage. In the event that these materials have been subjected to external force that have resulted in surface sifting or flaking, consideration should be given to either removal or encapsulation with a sealer. The overall concern, of course, is the possibility of exposure to respirable asbestos fiber. Only on-site breathing zone determinations will determine exposure concentrations, if any. OSHA has regulations for air moniotring in the event that such action is necessary. Thomas P. Feit Regional Manager W. R. Grace & Co. TPF/jdy 0261*7176 j 12 February 1982 r W.R. Grace Co. Zonolite Division 6851 Smith Avenue Newark, CA 94560 Gentlemen: In 1964 I specified "California Zonolite" as the sprayedon interior coating of a structural metal roof deck for thermal and acoustical insulation. {The metal roof deck is the exterior weathering surface as well as the structure). The building is a residence. The owners have inquired if there is any asbestos in their insulation, which is the ceiling surface of their home. Can you advise if asbestos was a component of the material specified in 1964? Tjiank you for your help in this matter. cc: Mr. & Mrs. Jack Wahrhaftig