Document xdM0GvbEjrk3vo5MR2y3EOxOg

COPY Dr. D .V, N. Hardy Dr. H.R. Newman te511A]lfc-Oiiefnlcal Company: St. Louis, Missouri. September 22, 1955 Dr. J.W, Barrett London Office AROCLOR TOXICITY On rereading my memo of September 20 to you I noticed an error in the second paragraph. I feel that this corres pondence is sufficiently important to correct this para graph. ' This paragraph should reads You commented in your letter about the difference in toxicity between Aroclor 1254 and 1242. These differences are not surprising because in the earlier work it was found that toxicity increased with degree of chlorination. Of course, the vol atility is important in the case of inhalation toxicity, and absorption into the intestinal tract is important from the point of oral toxicity. Frankly, there was not a great deal of difference between the two subject compounds. As you know, the maximum allowable concentration is 0.1 mg/cubic meter in the case of 1254 and is as high as 10.0 mg/cubic meter in the case of 1268. I think the former is too low and the latter is too high. In the United States they don't use maximum allowable concentrations (MAC; very routinely but certainly in England I think it would be alright to consider 0.2 mg/cubic meter as perfectly safe. REKik R. Emmet Kelly, M.D TRAN 019924 COMPANY CONFIDENTIAL WATER_PCB-SD0000033552