Document MMj28155BMp5Z0QomrkeD11va

INDUSTRIAL HYGIENE FOUNDATION OF AM ERICA, I N C. Me l l o n In s t it u t e , 4400 Fif t h Av e n u e Pit t s b u r g h , Pa . 15213 September 5, 1967 Dr. Robert A. Kehoe 345 Resor Avenue Cincinnati, Ohio 45220 Dear Dr. Kehoe: At the Lead Symposium apparently Dr. Ronald E. Lane equilibrated 80 fig. of lead per 100 ml. with 80 mg. per 100 grams of whole blood in applying the threshold for safe occupational absorption in his tables. A.National Research Council Report, "Standard Values in Blood, " dated July 1951 (Air Force Technical Report No. 6039) gives values for blood lead in weight/volume derived from a gravimetric method which assumes the specific gravity of blood to be 1. 056. I have received the attached letter from Colombia, South America asking if it would be permissible to transpose weight/volume to weight/weight. As the Colombian regulation already has a 12. 5% safety margin, i. e. , a threshold of 70 mg. /100 gm. , it would appear that a transposition such as is suggested would raise the safety margin to 18+%. This could add a significant burden of work to the analytical laboratory, unnecessarily producing anxiety from the requirement for repetition of analyses, and perhaps loss of work and income by employees. Don't you feel they should switch to the weight /weight method of reporting? Best regards. Sincerely, deT:sjc Robert T. P. deTreville, M. D. Managing Director N20289