Document qkoKkaYBdbO1xpvQG1M43jpK5

Resea r ch La b o r a t o r ies Div isio n GENERAL M OTORS CORPORATION POST OFFICE BOX 188, NORTH END STATION D ET RO IT 2, M IC H IG A N July 20, 1949 Dr. Robert A. Kehoe, Director Kettering Laboratory of Applied Physiology University of Cincinnati College of Medicine Cjincinnati 19, Ohio * Dear Bobs I thank you for your letter of June 16 in -which you express your opinions regarding probable causes of ele vated concentrations of lead in blood and urine of employees engaged in the application and removal of a high lead, low tin solder* I don't have to tell you ijhat we have a very high regard for your opinions* We have made observations and tests at the plant concerned and these indicate that in this plant, as -well as in others where we have made tests for air-borne lead, excessive exposures are not found around tinning, torch soldering, arid wiping operations. They are found vjhereever mechanical grinding or sanding of solder is done and they may occur from vigorous hand-sanding, but prob ably not from hand filing. It appears to me that these results more or less Eliminate the necessity for consideration of the vapor and fume angLe you mentioned. For that reason I ques-' tion the value to us of tests to determine the amount of vapor and fume evolved from the different lead alloys at our working temperatures (below 650 F.). After further consideration of the field data collected, along with your opinions and suggestions, if studies of the nature you mention are desired by our executives, we shall contact you further. Again let me express my appreciation of your reply to our questions. Best personal regards, FAPigc F. A. Patty, Head Industrial Hygiene Dept.