Identical Letters Sent To: Dr. W. J. Bair Manager, Biomedical and Environmental Research Program Pacific Northwest Laboratory P. 0. Box 999 Richland, Washington 99352 Dr. Roy Thompson Biology Department Pacific Northwest Laboratory P. 0. Box 999 Richland, Washington 99352 Dr. Roger McClellan Director, Inhalation Toxicology Research Institute Lovelace Foundation for Medical Education énd Research P. 0. Box 5890 Albuquerque, New Mexico 87115 Dr. Jack Healy Health Division’ (2 we hag Alamne Scientific Laboratory P. Q. Box 1663 Los Alamos, New Mexico 87545 Dr. John Harley Director, Health and Safety Laboratory U.S. ERDA 376 Hudscn Street New York, New York 10014 Dr. William Templeton Pacific Northwest Laboratory P.O. Box 999 Richland, Washington 99352 Dr. Chester Francis Oak Ridge National Laboratory P. OQ. Box X Oak Ridge, Tennessee 37830