Document Zx4a7RKVY13e3aEZ6eKjwQGY

Ii MIDLAND, M ICHICAN October 3, 1958 PLAINTIFF'S EXHIBIT DOW-1387 ST0CI6804 Dr. C. G. Kramer Medical Department 607 Building EXPOFURE TO AFEEFTOF FIBERF BY ROBERT FRIDAY, PIPE FHOP DEPARTMENT Robert Friday began work ar a Dine coverer on 11/5/51, with the classification "Apprentice Heloer." On ll/5/5^' he was advanced to Fenior Helper and on 5/19/53 to Journeyman Pine Coverer. He has continued in thiF classification to date. The work of the oioe coverer, including all job classifications, is entirely with a multitude of pipe and tank covering operations. It is estimated by puoervision tnat approximately 10% of a man's time is spent in using a small hand saw to cut the covering mater ial. Eighty oer cent of the time is spent fitting material and another 10% is used to mix an insulating cement and form bends. It is evident that in sawing the insulating material, and in the mixing of the insulating cement, exposure to fine duFt can occur. Attached is a table showing the resuits of a study of dust exposure of workers cutting various types of p- >e covering material used at the Dow Corning Corporation. The material most widely used by Dow workers is Carey's "Air Cell," an asbestos fiber material built up of alternating layers of plain and indented asbestos paper of ?? layers per inch, with a density of nine pounds per cubic foot. Samples of Carey's Air Cell were analyzed by X-ray diffraction and shown to be chiefly c'nrysotile with five to 10% of the sample brucite, which is magnesium hydroxide, and <5% magnitite, which is Fe,0.. The Johns-Mansville High Temp which is shown in the following table as calcium silicate, actually was shown by analysis to be for the moFt part (in the crystalline phase, that is) cristotalite in the form of SiO-,, with both chrysotile and amphibole forms of asbestos present -- probably 10 to ?0% of each. There was an indication of the presence of amorphous material which is probably the calcium silicate mentioned in the summary of mater ials used. A copy of the analytical report is included with this letter. If one assumes that hand sawing of the Carey Air Cell will give rise to about the same amount of dust in the air as the hand sawing of the materials studied at Dow Corning, aooroximately 5 - 10% sawing of this man's time was spent in an environment where the dust con centration of asbestos and crystalline silicon dioxide particles 411591 Dr. C. G. Kramer 2- 10/2/68 ranged between tan and twenty millions of particles per cubic foot. The Industrial Hygiene Standard both for asbestos fibers and for silica is five million particles per cubic foot. It should be remembered, however, that this Industrial Hygiene Standard is for reoeated exposures of eight hours per day rather than the 5 - 10% of the man's time which is estimated to have been spent in atmospheres containing the ten to twenty million particles per cubic foot of dust. It would appear, therefore, that the likelihood of either asbestosie or silicosis resulting from these exposures is extremely low. It is true, however, that there is the possibility of asbestos particles in the air and therefore, asbestos might be found in the lungs of a pipe coverer. A Dow material usage report for 1966, indicated the following and is considered to be typical of the proportionate amounts used. Pipe Covering Material Quantity Board Ft. Per Cent Carey "Air Cell" (asbestos fiber) Owens Corning Fiberglas SSL Owens Corning Hi Temp. Fiberflas Owens Corning "Kaylo" (Calcium silicate) Johns-Mansville Hi Temp. (Cal. silicate) 75,971 11,56 1 1,796 58, 148 245 147,722 51.4 7.8 1.2 39.4 0.2 Owens Corning "Kaylo" l(calcium silicate) Johns-Mansville Hi Temp. (cal. ilicate) Block Material 12,334 sq. ft. 245 sq. ft. 12,579 sq. ft. cn sroor.ao E. J. Schneider Biochemical Research Laboratory 1701 Building EJS reh Enc. 411592