Document XOkzzBdnQ5QBQ7M2m1ZKDno6G

FILE NAME: DuPont (DUP) DATE: 1966 May 20 DOC#: DUP068 DOCUMENT DESCRIPTION: Memo from Employee Relations Dept to General Managers, etc. RE Threshold Limit Values ij JJMPLOYEE RS. -ATIONS DEPARTMENT yu cay Copy to; DV.icHe .PrDeaswidseonnt GV.iceE.PrHeoslibdreonotk May 20, 1966 File OH - 430 TO: . GCEHNIEEFRAENLGMINAENEARG,ERESNGINEERING DEPARTMENT DDIIRREECCTTOORR,, CDEENVTERLOAPLMREENSETADRECPHARDTEMPAERNTTMENT THRESHOLD LIMIT VALUES On April 19, 1966, the MCA Board of Directors, upon recommenda tion of its Medical Advisory Committee, approved the attached policy statement concerning Threshold Limit Values. In it, member companies are urged to give favorable consideration to the establishment of surveillance facilities and related medical program as suggested in the statement. The importance of Threshold Limit Values to the chemical industry . lies in the fact that, as issued by the American Conference of Governmental Industrial Hygienists, they are intended to be unofficial guides to good indus trial hygiene practice, but are now being adopted by an increasing number of states as legal limits of exposure of workmen. The engineering cost of com pliance with such limits is such that the chemical industry has an economic interest in seeing that the Threshold Limit Values are valid, but not more re strictive than is necessary for the protection of the workers' health. Our Company is doing a commendable job in protecting the health of its workers. It does this by establishing a priori engineering guides for safe exposure limits and through continued medical observation of the workers. -2In general, it has not been necessary for the successful operation of this program to determine quantitatively the actual day-to-day exposure of the workers on the job. As a result, favorable Company experience can seldom be used to validate or refute a suggested numerical Threshold Limit Value. The chemical industry can, if it wishes, have a positive influence on Threshold Limit Values, but only if it can relate quantitative exposure levels to effects or lack of effects through documented medical observations. It would appear desirable for each department, in consultation with the Medical Division and Haskell Laboratory, to consider the expansion of its employee health program to include the accumulation of data on the levels of employee exposures to those atmospheric contaminants which may be significant in your operations. Questions pertaining to this subject should be directed to Dr. J. A. Zapp, J r., Extension 81-3771. Additional copies of this letter and the attachment may be obtained by calling Extension 81-3767. Attachment G. G. MITCHELL, DIRECTOR \ \ POLICY STATEMENT APPftOVED BY MCA BOAPD OF DIRECTORS ~ April 19. 1066 THE SIGNIFICANCE OF THRESHOLD LIMIT VALUES TO TFP CHEMICAL INDUSTRY As defined by the American Conference of Governmental ' Industrial Hygienists, ''Threshold Limit Values refer to airborne concentrations of substances and represent conditions under which It Is believed that nearly all workers may be repeatedly exposed, day after day, without adverse effect." They say further, "The Conference does not consider the Threshold Limit Values appropriate matter for adoption in legislative codes and regulations, and recom mends against such use." In spite of this last statement, an effort was made to incorporate Threshold Limit Values (TLV) as part of a code for safe operation by government contractors subject to the Walih-Healey Aft. There has been a persistent and increasing ten ' > . dency by governmental agencies at various levels and by the courts to consider the TLV lists as regulations. In face of this, it is not unreasonable to expect that efforts will continue by certain in dividuals and groups to press for incorporation of TLV's into various - . codes. . Industry in general and the chemical in lustry in particular have a vital interest in ensuring that the TLV cf a substance is fac tual and realistic because on the one hand industry has a real need for reliable guides to help achieve safe work environments and pre vent Illness, and on the other environmental control of a substance is costly and is disproportionately more expensive as established limits approach z?ro. - 2- Thrc hold Limit Values are based upon the best available information from industrial experience, from experimental human and animal studies, and when possible, from a combination of these. In practice, the majority of limits are based upon observations uerived from animal experimentation. It is seldom that valid observations on experience in humans is available even though this is by far the most desirable v;ay to validate a TLV. If the experience of workmen who use toxic substances is to have meaning in validating a TLV derived from animal experimental work certain criteria must be met. The exposure of workmen must be defined quantitatively in terms of amount of contaminant and duration of con- tac,,, and the effect or lack of effect must be jetermined hy appropri ate medical and laboratory procedures. Medical services in industry may alrctady have available significant numbers of observations on the health of workmen. In some cases the observations may be somewhat less than acceptable and In others they may be excellent. In most cases the medical information is useless in validating a TLV because quantitative data on environmental exposure levels is not available to support the medical observations. ~ - Events of the recent past Justify the prediction that TLVs will play a greater role in the regulation (direct or indirect) of industrial operations in the near-term future and that validation of TLV's will be of vital importance to industrial management. There fore, the Medical Advisory Committee of MCA urges that member com panies give serious consideration to establishing or expanding in plant surveillance of environmental contamination by chemicals, and that this be combined with an appropriate medical program to define the impact of the environment on the worktaen. Tje data derived from such studies should, at an appropriate time, be considered for sci entific publication or submission to the' Committee on Threshold Limits of the American Conference of Governmental Industrial Hygien ists to establish, support, or refute the value for any specific material.