Document XRwbv9ggwrdbkrZGJrqK9RDDR

FILE NAME: WR Grace (WRG) DATE: August 25, 1972 DOC#: WRG269 DOCUMENT DESCRIPTION: 1972 Letter to Dr. Stokinger from JJ Marino regarding quartz and cristobalite in non-asbestos insulation 212 LR 3-3444 Q uigley company, inc. 2 3 3 E . 4 2 N D ST. N EW Y O R K . N. Y. 10017 August 25, 1972 Dr. Herbert E. Stokinger Chief, Toxicology Branch Div. of Laboratories & Criteria Development Dept, of Health, Education & Welfare 1014 Broadway Cincinnati, Ohio 45202 . Dear Dr. Stokinger: Referring to your letter of July 5 and our subsequent phone conversation concerning quartz and cristobalite in our non-asbestos insulation Panelex, I have contacted our suppliers of perlite, dicalite and vermiculite. The replies were as follows: Perlite (9% of product formulation) Our supplier "Pennsylvania Perlite Corp. Mforwarded a lab report by Walter C. McCrone Assoc. Inc. of Chicago, 111. indicating the total free silica to be less than 0. 05%. Dicalite (2. 5% of product formulation) Our supplier, Grefco, Inc. forwarded to us a lab report from George D. Clayton & Assoc, and an article "Pneumoconiosis in Diatomite Mining and Processing" by USPHS. Although the quartz content is less than 1% the cristobalite analyzed at 61%. This cristobailite fraction calculates out as being 1. 5% of the total product. , Vermiculite (26% of formulation) The attached letter from our supplier W. R. Grace indicates free silica to be le ss than 1% (limit of their detection). We must apologize for the inconvenience of reviewing this again. However, I feel I now know the basic requirements and hopefully in the future I can present all the data at once. A Subtidiary of PFIZER . INC. Dr. Herbert E. Stokinger August 25, 1972 Page 2 Based on the above we feel your previous opinion is still valid and the only modification to your July 5th. letter is to remgjjjjyi^^ concerning a 3% quartz content. If this can be done we would be very grateful. Very truly yours, y.yflasLvp J. J. Marino Chief Engineer Enclosures JJM /sb .. % / v. n riurx.i III I) \