Document b6pDGa4nNzvyQgVeLk36Noj0

- 29 - REPORT OP THE C02UTTEE Oil THRESHOLD LIMITS , . * -r ' * JJR f* PAIREJMX,- (U. S. Publio Health Service) i It is obviously difficult, where a large number of substances is involved# to review the allowable concentration values In detail at an annual meeting. Fbr that reason, provision ,\waa made early in the organisation of the American Conferenoe-of Governmental In- /^dustrial Hygienists for a Committee on Threshold Limits to study this question and to.report to the'Conference at its annual meeting. The composition of this Com mittee is not fixed but is changed by annual appointment and the threshold limit ^'values are similarly maintained in a fluid stato by annual revision. For a number 'of years the Coamittee has subjected these values to oereful scrutiny and attespted to bring them into close conformance with practice. .. of Vns i: *,r V A?*.4 Durlhg present year, it was folt that the ooncept of maximum allowable values had now reached a stage where more, extensive participation of the members of the Conference in the formulation of these values based upon personal experience in the field would be of deoided assistance. This year# therefore, your Committee hes for the first time, I believe, made a direct attempt to obtain a statement from each member of the Conference with reference to tho annuel threshold limit values end helpful. the Vr-e"soVonsefrom-th' e lndiv. idir.1 nembers has been. most generous and `i ,* *.,..** / In view of the* annual revision of threshold limit velues,it has been the pur pose of the Conference to seek values which, on the one hand protect the individ ual workman, and on the other would imposo no impossible burden on the manufac turer, This balance Is difficult to achieve but can be attained by just such a series of adjustments as is provided for in the Constitution of the Conference, i There is no industrial poison so potent, sp virulent, that it cannot be manufac- f tured safely under carefully controlled conditions. The manufacture end wide spread use of such a substance as lead tetraethyl and tho preparation of extremely poisonous war gases are good illustrations of this. In fact, the chemical manu facturing Industry in general has been able to maintain a high standard of safe industrial practice by the installation of suitable control measures for the pro tection of its workers. There is no reason why euch safe industrial control measures cannot bo extended to industry in general wherever industrial poisons occur. r< ' In addition to the cbnsnonts of the members of the Conference, a few criti\ cisms from other sources have reached ust concerning tho 1947 values. These may be briefly summarized as follows: 1. Concerning the membership at large, criticism has taken the form that (a) vnlucs were arrived at by consulting tho membership at large, and (b) thet ' the members were not consulted. * * 1 2 *3 t* 2. The publication of the values in the Industrial Hygiene newsletter mode it appear that the values were those of the U. S. Public Health Servioo. -whether ;'this was wishful thinking or not,, the source of the 1947 voluee woe dearly in- dicatcd at tho time of publication. ---------- : \ ' .. . . ; -. r*' - ` f 3.*' Criticism has cIso taken .the form that the values given wero not arrived --e*4 at .or baeed upon scientific evidence. The latter has particularly interested . . .. .. ... ,, /-. .20- ; ' Vai* . . ' V S.-U'.o ' . .T:^. 2C0 ' .