Document aDr6K4Z1jm87Yn6dJrjJqE1oN

C08FIDEHTIAL TO: DR. J.W. BARRETT. DVMH/toBB . c.o. Dr. J.A. Gardner. Dr. W.KoG. Morgan. Mr. W., Hamer. Mr. C.G. Wickham Dr. H.R. Reman Dr. D.S.P. Roebuck Mr. J.S. Hunter Mr. E.L. Pixton Mr. H.G.H. Thomas. Mr. J.A. Brindle. 6th Deoenber 1955 AROCLORS TOXICOLOGICAL EXAMINATION * Since communication of 19th August 1955> when I sunned up the position confronting ue following the receipt of the reports of the Kettering Laboratory/ Dr. Hevman has discussed with Dr. Kelly the significance of the Kettering results in relation to M.C.C. thought and polioy. M.C.C.'s immediate action is to submit the reports to the American Conference of Governmental Industrial Hygienists in support of a claim that the offieial table of maximum permissible Tapours concentrationsdbould include the. items:* I 42Jt Chlorinated Diphenyl (Aroclor 1242) 54Jl * * (Aroclor 1254) 2 mgrme./m3 1 mgrm./m^ ' The Kettering results indicated in brief that prolonged exposure to Aroolor 1242 vapour at 1.9 mgrm./m' gave no sign of danage to the test animals but that; Aroclor 1&54 at 1.5 ngrm./n3 caused slight but positive signs of injury.*' Iou will note that M.C.C. do not introduce a safety factor in translating these snimal test results to huaan beings, end in faot regard such a faotor as unnecessary in animal teats of suoh thorough ness as those carried out at Kettering. It will be sometime before we know the decision. In ay view it would not be nnreelietio to assign a rains of 2 mgrm./V te Aroolor 1242 but the ease for setting the limit at 1 mgra./m^ for Aroolor 1254 is not so logical. After all 1254 can cause alight but perceptible danage at 1.6 ngrm./n3 and who oen soy whether It would be harmless at HONS 095188 WATER PCB-SD0000017766 1 mgrm./m^. However, if the M.C.C. recommendations are accepted there will be an implication that Aroolor toxicity increases with chlorine content, a reversal of the position suggested in M.C.C. technical literature. M.C.C. Application Data Bulletin No. P-115 states "If Aroclore are used at elevated temperatures such as 200 or 3C0C. in open systems methods must be designed to exhaust any vapours arising from these open systems. This applies especially to lover chlorinated Aroolors where experimental work on animals indicates that the maximum safe concentration in workrooms ie in the range of 0.5 - 1.0 milligrams per oublc meter of air. In the case of more highly chlorinated Aroclors such as Aroclor 1268 the allowable limit is about 10 milligrams per cubic meter of air and accordingly. Aroclors of this type are believed to be of a much lower order of toxicity. Whatever the outcome, there will be no impact on H.C.C. policy regarding the use of Aroolors in paints since M.C.C. have long ceased to recommend the use of Aroclors for this purpose. However, M.C.L. has oantinued to offer Aroclors for use in paints on the basis that tbs evidence for rejection was slim, and that the risk is reduced by resorting to the nee of more highly ohlorinated Aroclors. ThiB v&b thought to have the duel advantage of using a material of (a) lower intrinsic toxicity (b) lower vapour pressure. It is now dear that toxicity increases with degree of chlorination and that this effect may canoel or even outweigh the.advantage due to decreased vapour pressure. We have tended to draw a distinction between the use of Aroclors in latex paints cn the cue hand and in conventional paintB on the other, the ooccenBUB of opinion being that the rate of volatilisation from the former is greater than from the latter, and as a result we are no longer recommending Aroolors for latex paints. Tbs decision now before us is whether we should continue to sell Aroolors for ubs in conventional paints. On tills issue, the reoent decision by I.C.I. to discontinue their usage of Aroolors in ordinary paints is considered to be an indication of the line that nay well b taken by our other customers. Broadly speaking the main objections are that the paint manufacturer oannot eontrol the paint user who may apply in the form of spray, and may nee on hot surfaoes. In either case a degree of risk must be admitted. As to bow serious the risk may be it depends naturally on the total time for which any individual is exposed during his life time. There must dearly be ciroumstanoes under which the use of Aroolor oontwining paints will con stitute a health hasard, particularly to individuals whs for one reason or another are constitutionally less resistant than the norm. The I.C.I. decision must have been influenced quite materially by a letter from Dr. Kelly to Mr. Boy Wlttersohein (dated 15.7.55.), a oopy ef which reached them through Canadian Industries ltd. The relevant passages are as follows:- - MQNS 095189 WATER_PCB-SD0000017767 f i '' V ` jv ! I \ V i( -3- Aroclor should not be sprayed on the job Id an industrial plant where there are plant personnel who can breathe the vapours. there is no danger at all if the material is brushed on, and there is no danger in Bpraying it if the workers use a booth or use an approved respirator and no one inhales the spray. Aroolor fames at rooa temperature very probably would not present any hazards. Mist or spray, however, is another problem entirely and that is the reason for the above recommendation. After all, the toxicity of Aroclor must take into consideration how much can get into the air. It is our belief that at room temperature not enough can get into the air to cause any trouble. At elevated temperatures and if the material is dispersed as a mist or aerosol a different Interpretation has to be placed on its toxicity*. The passages of particular significance to I.C.I. Paints are underlined and mey be considered to be reflected in their conclusions which 1 now quote below:- In brief (a) The spraying of Aroclor pointB appears to involve precautions which would be so inconvenient as to limit unduly their application by this method. (b) Apart from questions of spraying there appear to be cases where Aroclor-containing points would involve toxic hazards either during appli cation or subsequently, and where cautionary advice would be appropriate. The need for Bpecial precautions would limit the use of Aroclor painlB in -these caBes. (c) As far as the paints in question are ecoeerned it is impossible to know bow aaj particular oan may be eventually used, so every can would need to show the warnings and precautions for all foreseeable eventualities. The presence of these warnings would tend to deter people from using the paints even in oases where no Bpecial precautions ware needed.* With reference to the impression generally given that cold Aroclors are safe, recent determinatione of vapour pressure (Southern Research Institute Final Report to M.C.C. on Projeot 526 by W.M. Rolan) permit the saturated vapour ocnosntrationa to be calculated as follows:- Vapour.Concentration (mgrm,/m3) Aroclor 1242 Aroclor 1248 Aroclor 1254 20C. 4.7 2.1 0.8 A 8.2 3.0 1.1 MONS 095190 WATER PCB-SD0000017768 -4- Henoe air Batura ted with cold Aroclor ie at or above the maximum permissible conoentration. In general we hare to accept Dr. Kelly's leading remarks and the conclusions of 2.C.I. Paints, but any consideration of the risk under a given set of conditions must involve the total exposure factor as well as the concentration. It is in this area that constructive answers could be made if the necessary background of data were available. However, the issue before us is whether ri.C.L. should align ite policy on the use of Aroclors in paint with that of M.C.C., and as I see it we have little alternative when M.C.C. can be quoted against us. The use of Aroclors in paints based on chlorinated rubber warrants special consideration in view of the following circumstances (a) Aroclors are of such value for the purpose that the manufacturers might well be * embarrassed if we withdraw our recommendation (b) they are not used for ordinary decorative and protective purposes in domestic and industrial premises, but to protect metals from corrosion, (o) they are cot applied to hot surfaces under conditions whioh would constitute a hazard to nearby personnel. ' My recommendations are accordingly as follows;- 1. M.C.L. continues to Bell Aroclors for ubc in the manufacture of paints based on chlorinated rubber. 2. M.C.L. continues to sell Aroclors for production of paints intended for exterior application. 1. M.C.L. discontinues the sale of Aroclors for use in the manufacture of all other paints. D.V.N. HARDY HONS 095191 WATER PCB-SD0000017769