Document npdj4wXJwVGdaq8gmGzbm6E61

CQSFIDSMTIAL TO: DR. J.W. BARRETT. DVMH/toEB . c.o. Dr. J.A. Gardner. Dr. W.KoG. Morgan. Mr. V.E. Hamer. Mr. C.G. Wickham Dr. H.R. Reman Dr. D.S.P. Roebuck Mr. J.S. Hunter Mr. E.L. Piston Mr. H.G.H. Thomas. Mr. J.A. firindle. 6th December 1955 AROCLORS TOXICOLOGICAL EXAKLNATIQK * Since sy communication of 19th August 1955, when I summed up the poeition 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.'e 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 vapours concentrations should include the. items:* I 42Jt Chlorinated Diphenyl (Aroclor 1242) 54Jl * * (Aroolor 1254) 2 mgrms./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 damage to the test animals but that'Aroclor 1&54 t 1.5 mgrm./m3 caused alight but positive sign# of injury.*' Iou will note that M.C.C. do not introduoe a safety factor in translating these animal test results to human beings, end in fmot regard such a fmotor ms unnecessary in animal tests of such thorough ness ss those carried out st Kettering. It will be sometime before we know the decision. In my view it would not be unrealistic to assign s value of 2 ngm./iK te Aroolor 1242 but the ease for eetting the limit at 1 mgra./m^ for Areolor 1254 is not so logical. After all 1254 can cause alight but perceptible damage at 1.6 mgr*./m3 and who earn say whether it would be harmless at MONS 095188 TOWOLDMON0046080 WATER PCB-00037057 -2_ 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 Ho. P-115 stateB "If Aroclor8 are used at elevated temperatures such as 200 or 300C. in open systems methods must be designed to exhaust aaj 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 is in the range of 0.5 - 1.0 milligrams per cubic meter of air. In the case of more highly chlorinated Aroclors such as Aroclor 1268 the allowable limit 1b about 10 milligrams per eubie 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 oootinued to offer Aroclors for use in p&lntB on the basis that the evidenoe for rejeotioc was slim, and that the risk is reduced by resorting to the use of more highly ohloiinated Aroclors. ThiB waa thought to have the duel advantage of using a material of (a) lower intrinsic toxicity (b) lower vapour pressure. It is now clear that toxicity increases with degree of chlorination and that this effect may oanoel or even outweigh the.advantage due to decreased vapour pressure. Ue have tended to draw a distinction between the use of Aroclors in latex paints on the cue band and in conventional paintb on the other, the ooncensuB 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 reoommsndlng Aroolors for latex paints. The decision now before us is whether we should continue to sell Aroolors for use in conventional paints. On tills issue, the reoent decision by I.C.l. to discontinue their usage of Aroolors In ordinary paints is considered to be an indication of the line that may veil fae taken fay our other customers. Broadly peaking the main objections are that the paint manufacturer oennot oontrol the paint user who may apply in the form of spray, and may use on hot eurfaoee. 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 circumstances under which the use of Aroolor containing paints will con stitute a health hasard, particularly to individuals whe for one reason or another are constitutionally less resistant than the nor*. The I.C.l. decision must have been influenoed quite materially by a letter from Dr. Kelly to Mr. Hey Wittersohein (dated 15.7.55.), s copy of which reached them through Canadian Industries Ltd. The relevant passages are as follows;- - HONS 095189 TOWOLDMON0046081 WATER_PCB-00037058 f ( -3- Aroclor should not be sprayed on the job Id an industrial plant where there are plant perBOP^wl who nn breathe the vapours. there is no danger at all if the material is brushed on, and there is no danger in spraying it if the workers use a booth or ubs an approved respirator and no one inhales the spray. Aroolor fumes 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 reooanendation. After all, the toxicity of Aroclor oust take into consideration how much can get into the air. It is our belief that at rooa 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 l.C.I. Paints are underlined and mey be oonaidered to be reflected in their conclusions which 1 now quote below:- In brief (a) The spraying of Aroclor paintB 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 wcwld be appropriate. The need for special precautions would limit the use of Aroclor paints in -these caBes. (c) As far as the paints in question are ooucerned it is impossible to know bow aaj particular oan may be eventually used, so every can would need to show the warnings and preoautiona for all foreseeable eventualities. The preaenoe of these warnings would tend to deter people from using the paints even In oases where no special precautions ware needed.* With reference to the impression generally given that cold Aroclors are safe, recent determinations of vapour pressure (Southern Research Institute Final Report to M.C.C. on Projeot 526 by W.M. Rolan) permit the saturated vapour ocnoentrationa 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 TOWOLDMON0046082 WATER PCB-00037059 -4- Henoe air saturated with cold Aroclor is at or above the maximum permissible eonoentration. 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 Bet 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 M.C.L. should align its 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 withdrew 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 not 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. .3 M.C.L. discontinues the sale of Aroclors for use in the manufacture of all other paints. Mi D.V.N. HARDYJ MONS 095191 TOWOLDMON0046083 WATER PCB-00037060