Document RJgegd5KbRn0nDJD736nvdn8k

May 15, 1967 Seymour Calvert, Ph.D. The Chemical Rubber Co. 2310 Superior Avenue Cleveland, Ohio 44114 Dear Lector Calvert: 1 have looked over the two data sheets which you sent to me with your letter of April 7, and have tried to set down some data within the framework. The result is little more than nothing, beyond the well-known figure for the tolerable concentration of lead (without reference to any compound, or dimensions of particle, but presumably the worst compound, exclusive of the lead alkyls, and the most dangerous degree of dispersion). The fact is that this form of reporting does not fit the requirements for the effects of the concentration of metallic elements in the atmosphere. Not only does it not yield the desirable information, but it cannot fail to present the available information in a manner which will mislead the reader, by oversimplification of the facts. I do not believe any tabular presentation of the toxicologic information on lead will serve any useful purpose, especially in relation to air pollution, whereas a short statement containing a few tabular data ss to physical properties, etc. would convey most of the useful information. In that connection the Hygienic Guide on Lead (and there are certain other materials), put out by the American Industrial Hygiene Association (of which you can obtain copies) provide a body of useful information in a manner that might well suggest to you how this could be done. As to lead in the ambient air, no standard can be promulgated on sound information at present, except in relation to the biological and toxicological information that must be supplied as the basis for criteria. I should be glad to provide the pertinent information now available, but I simply cannot drop what I aa engaged in to design a new fora for its presentation and to sort out and document the details. And frankly, I don't think the task is worth doing in this form, in relation to pollution of the ambient atmosphere. Sincerely yours. N20689