Document Bav84BjR0r5w2VvJnkwewYqE

C H l C AGO February 12, 1$?1|2 Dr. Robert A. Kehoe Kettering Laboratory Univ. of Cincinnati Cincinnati, Ohio Dear Dr. Kehoe: Thank you very much for your letter of February 9 which is most reassuring since we would never con sider a package of tooth paste in which lead con tamination were 200 p.p.m. or more. It is of course possible that such -lead as is con tained might reasonably be concentrated at the sur face so that after a large number of lead-free brushings, one brushing might contain as much as 1 milligram of lead. It is also conceivable that this last brushing con taining 1 milligram of lead might be swallowed in its entirety or that such a claim might be made. In this light we have at frequent intervals heard stories of children who have swallowed an entire tube of tooth paste. You have cited as a typical case the possibility of a daily absorption of O.OI4. milligrams of lead from tooth paste. Let us suppose that due to irregu larity of distribution of the lead, no lead were absorbed for 29 days out of the month, but that on the JOth day the full 1.2 milligrams were absorbed. Would this alter the picture with respect to poten tial danger? Rephrasing the question would clarify my thought if possible. If the accumulated absorption of 1.2 milli grams of lead over 30 days is tolerable, would it still be tolerable if this absorption were concen trated into one day out of the 30 without increasing the total absorption over the 30 day period? Very tp^ly yours, :HR:1 'i'. jlf. Rider Technical Director