Document B8MX7Npm992drqqR6b8qog8X4

I.m |(V, tlrfl v * ^ * C11 b O F. Morgan E. I. du Pont oe Nemours & Company Wilmington, Delaware itm employee ablations department MAsr.CLL LABORATORY TOXICOLOGY ANO INOUfTKIAL MCOICINC January 10, 1968 KE^OSTH E. KEUFER * e:;g L 1285 I was pleased to hear from you yesterday that consideration is trine Given to monitoring the dust levels at 21 construction sites around the country at regular intervals. I should like to suggest that some of these dust samples be examined for asbestos so that not only will the total count be known but also what fraction of the count is asbestos. A further point that is important at the moment is the type of asbestos being used. Since there is some evidence (but certainly not enough for a dogmatic statement) that the type of asbestos may be important in determining whether cancer is produced. At this time crocldolite is felt to be possibly more of a risk than chrysotile or amoslte. In line with this current feeling, I am enclosing the tentative values being suggested by the A.C.O.I.H. for the TLV for Asbestos. The recommendation made is nothing but a proposal at this time but la indicative of the trend of industrial hygiene thinking. Unfortunately these tentative TLV's are often taken as prime facie evidence by labor unions and state regulatory bodies. A further straw in the wind is a recent report on smoking amongst asbestos workers which indicates that the non-smoking asbestos worker has a slightly Increased chance of dying of chest disease compared with the non-smoking non-asbestos worker but that the asbestos worker who smokes shows a much higher death rate due to respiratory disease than does the smoker who Is not exposed to asbestos. In summary, it seems essential to know: 1) The dust exposure 2) The type of asbestos 3) ft}* state of health of asbestos exposed workers at least at the time they are hired and at the time of discharge. Z have spoken to Jim Morgan about the matter of reading the dust counts, and we will be sending you a cost estimate in,the near future * GJS/pgh Enclosure u; 0.- J-. Stopps, M.B.,B.S. Chief. Physiology Section ' OGiSOO. SETTER TMINOS PO SETTER LlVlNe .. . TMROUOM CHEMISTRY DUP 0900920 SC-DP-02160