April 17, 1988

R. P. Hancock, CIB Alcan Aluminum Corporation Post Office Box 6977 Cleveland, Ohio 44101-1977 Dear Mr. Hancock: This is in reply to your letter of February 22, regarding the necessity of continuing to maintain a Material Safety Data Sheet (MSDS) for alpha-Alumina (Al2O3). Alpha-Alumina is part of the floor of hazardous chemicals since the Occupational Safety and Health Administration (OSHA) regulates "nuisance dust" by 29 CFR 1910.1000 and Al2O3 is listed in Appendix D to the Threshold Limit Value (TLV) list of the latest edition of the American Conference of Governmental Industrial Hygienists (ACGIH). All substances, such as alpha-Alumina listed in Appendix D of the TLV list must be evaluated using the procedure for hazard determination outlined in 29 CFR 1910.1200(d). The company's written hazard determination is to describe the process followed, such as the sources of information consulted (OSHA, ACGIH, Registry of Toxic Effects of Chemical Substances) and the criteria used to evaluate studies. Health hazards based on at least one positive study conducted in accordance with established scientific principles and demonstrating statistically significant evidence must be listed on an MSDS. We hope this information will be helpful to you. If we can be of further assistance, please feel free to contact us again. Sincerely, Thomas J. Shepich, Director Directorate of Compliance Programs

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