Document Yy0GywoqYQzN3werVavKK33K

UNION CARBIDE CORPORATION MINING AND METALS DIVISION 270 PARK AVENUE, NEW YORK, N. Y. 10017 March 14, 1975 UC-3906 Mr. Lewis Cox, Special Assistant to the Assistant Secretary for Occupational Safety and Health Room 2115, Department of Labor Labor Building 14th and Constitution Avenue, N.W. V/ashingfon, D. C. 20210 'S^.CEXV C.LJ MAR 2 0 J975 UCC-CALIDRIA Dear Mr. Cox: This letter covers the substance of our conversations with Messrs. McClure, Gilbert, Reis and you at the OSHA offices on March 13, 1975, regarding clarification of the OSHA Asbestos Regulations relating to medical examinations. Union Carbide is actively engaged in the mining and milling of asbestos fiber at its plant in King City, California, and marketing its products throughout the United States and the Free World. In the main. Union Carbide's short fiber asbestos products can be characterized as serving specialty rather than commodity markets. For example, in 1974, 85 percent of our customers each purchased less than 50 tons of product. The most important specialty product in our line is ''Calidria" asbestos RG-244, a highly re fined fiber that has been coated with silica. This material is currently produced at a rate of about 1,000 tons per year and in 1974 about 45% of this material was sold overseas, generat ing a favorable trade balance in excess of one-half million dollars. The domestic consumption of RG-244 is spread among 72 users, of which only 8 consume more than 2 tons per month. Al though a 1,000 tons per year is trivial compared to conventional commodity asbestos uses, the dollar value is significant and this product is the cornerstone of our specialty business. "Calidria" asbestos RG-244 is used principally as a viscosity control agent for polyester resin at addition levels of about 1%. It has substantial performance and economic advantages over its principle competitor, pyrogenic silica. It is noteworthy that pyrogenic silica is not cur rently regulated by OSHA and thus RG-244, which is strictly regulated, must overcome a serious competitive disadvantage. The "Calidria" asbestos is generally added to the resin by the original manufacturer but frequently the end user also adds smaller amounts for special ad justment of properties. A majority of the resin is sprayed into molds, usually in conjunction with fiber glass, to form boat hulls, shower stalls, and various other reinforced plastic parts. The remainder is poured or "puttied" onto the mold or piece by hand. Some sanding or grinding frequently occurs in the finishing of the parts. j\ 0 8 6 2 2 UCC 014086 Mr. Lewis Cox -2- March 14, 1975 Union Carbide Corporation has conducted air sampling programs at a variety of industrial locations (l) where "Calidria" asbestos RG-244 was mixed with resin on both a "small" and "large" scale basis,.{2) where the asbestos-containing resin was sprayed, and (3) where the hardened resin parts were sanded or ground. The range of fiber counts found in each case is summarized in the following tables. Supporting data showing the details of the individual counts are available, if requested. ADDITION OF ''CALIDRIA" ASBESTOS RG-244 FIBER TO RESIN Operation No. of Samples Time Per Sample (Min.) Airborne Asbestos Ceiling Concentration (Fibers/cc >5u) "Large Scale" dumping of 100-450 lbs. Representa tive of polyester manufacturi ng. 8 8-24 0.5-2.8 "Small Scale" dumping of 1-12 lbs. Representative of small compounders. 9 2.5-25 0.4-2.0 The table above summarizes the data for the addition of "Calidria" asbestos RG-244 fiber to the liquid resin. The addition normally takes place over a time period of less than 30 minutes, usually only once or twice a shift. We should emphasize that the values reported are ceiling concentrations which would be averaged with the much lower concentrations present when asbestos is not being used to arrive at the prescribed 8-hour, time-weighted average (TWA) con centration. The highest number found, 2.8 fibers/cc, is well below the allowable ceiling con centration limit of 10 fibers/cc specified in Occupational Safety and Health Standards Part 1910, sI910.93a. Additional dust count data taken during spraying and grinding operations are summarized below: USE OF RESIN CONTAINING "CAUDRiA" ASBESTOS RG-244 Operation Spraying of polyester resin containing up to 1.4% asbestos. No. of Samples 12 Time Per Sample (Min.) 4-65 Airborne Asbestos Ceiling Concentration (Fibers/cc .> 5u) 0-0.6 Sanding and grinding of polyester parts contain- ing up to 3% asbestos. 15 A 08 62 3 4-49 0-0.4 UCC 014087