Document 65MbGpxbyK5zO3oDnzomvZMMm

UNITED STATES GYPSUM COMPANY October 24, 1975 John N. Harrington, M.D. Obstetrics -'Gynecology Medical Arts Center 221 7th Street Columbus, Mississippi 39701 ' Dear Dr. Harrington: . . This letter is in response to your inquiry concerning AUDICOTE Acoustical.Plaster prompted by a September 20, 1975 article in the Memphis newspaper, THE COMMERCIAL APPEAL. While we do not know with certainty that the product actually applied to the interior of your home is a United States Gypsum Company product, the specification you furnished with your letter so indicates and we are most happy to have this oppor tunity to comment on some aspects of the newspaper article. THE COMMERCIAL APPEAL article presents data apparently perti nent only to a specific set of conditions which exist when heating and cooling air is distributed, presumably in a commercial building, by way of a ceiling plenum. Typically, structural steel framing is present in a plenum and is protected with lightweight, asbestos-containing fireproofing compound Instead of Portland cement fireproofing. The fireproofing compound is different in terms of formulation and application than AUDICOTE Acoustical Plaster. Plena also house other services such as gas, water, sanitary plumbing, electric conduit, and telephone cable. Consequently, plena are entered frequently by servicemen for repairs and renovation to the service systems. Therefore, the possibility of damage to the unprotected fireproofing com pound in these confined spaces by service personnel does exist. I am unable to speculate on the amount of asbestos that was required to formulate the fireproofing encountered by the investigators named in the article; however, in the case of AUDICOTE Acoustical Piaster, the composition consists essentially Dr. John N. Harrington Page Two October 24, 1975_________ . : of expanded perlite, other inorganic minerals, and a foaming agent This composition produces the lightweight, open structure whifch accounts for its excellent acoustical and aesthetic qualities. AUDICOTE Acoustical Plaster contains only a minor amount of asbestos fiber which adds body to the wet mortar, thereby reducing its tendency to flow and sag on application to the - ceiling. More importantly, painting is customary in the course of normal decorating and I assume that the plaster in your home is painted. The paint provides abundant, protection against loss of any of the constituents of the plaster. We routinely recom mend a thin, spray-applied coat of vinyl latex ceiling flat paint appropriately thinned for spray application. A heavy coat of paint, or numerous applications of paint, will obviously impair the acoustical efficiency of AUDICOTE Acoustical Plaster. In summary, I am not aware of, nor can I conceive of, a hazardous exposure resulting from a properly installed and maintained AUDICOTE Acoustical Plaster. The conditions described in the newspaper article obviously emanate from a fireproofing compound, and the investigators admitted that this only occurs when accompanied by "directly visible damage to the sprayed material II .. Thanh you for the opportunity to provide you with our view of this newspaper article. Sincerely, Kenneth S. Freeman Senior Research Associate Research and Development KSF:mm bcc: #149 M. R. Helton