Document MMxoQkr6djLMXRB7OweGoKOKM

L'n_ "'T Es ^wil N rx 1" 1 B (conoco) Interoffice Communication To From Oat* SuD)*CT Paul Fetzer Tom Grumbles December 30, 1980 Comments on Evaluation of 3"M OVM Passive Dosimeter Badge COPY 1- v' Jim Hall and 1 have reviewed the report on the subject study. The results for EDC are reassuring and certainly justify the use of OVM's for monitoring personnel exposures to EOC. The results for VCH are perhaps.not .surpr is.ing but regardless are somewhat disturbing. Therefore, the following comments will be confined to the VCH results. From the results of the experiment we certainly would have to agree with your conclusions. Basically, it appears we^have a. method .that ..i s. precise,.but not. accurate^ for measurement of VCM air"concent rat ions. * However, as you state,' it is equivalent with the charcoal tube method. Whenever personnel monitoring is done to evaluate exposures, there are several issues of concern. The first, but not necessarily most impor tant, is compliance with applicable exposure standards. Charcoal'ad sorption, via a pump and tube or passive monitor, is recognized to meet the accuracy requirements for monitoring in the VCM standard. So from a compliance standpoint it is clear that we are monitoring with a suitable method. Another, and more important issue, is the level of exposure at which health effects occur and the ability of monitoring methods to determine employee exposure levels for comparison. As witnessed by your results, charcoal adsorption with current sampling schemes appears not to pro vide an accurate value for personnel exposure to vinyl chloride. In fact, your experiment results show that i^t^anjjjderestimate exposure levels by more than.501, at levels in the range "of 6.5-5.0 ppm. Assuming the experimental conditions are realistic in terms of field conditions this is a disturbing result. However as stated before, the standard says we shall not allow exposures to exceed 1.0 ppm based on their sampling methods.. We are doing this. From the standpoint of health protection, the worst case is that we may be underestimating employee exposures. The answer to this concern is more involved. Briefly stated, OSHA set the 1.0 ppm standard based on the regulatory policy of "lowest feasible level" of exposure for any identified carcinogen. There are no reported effects of vinyl chloride exposures in the range of 0.5-5.0 ppm. The American Conference of Governmental Industrial Hygienist, the group setting TLV values every year, has set an eight-hour TLV of 5.0 ppm for vinyl chloride. This group is not bound by regulatory policies and sets its recommended values oased on scientific evidence only. Therefore if measured ex posures of 0.5 ppm were actually in the 1.0-2.0 ppm range, I feel con fident that employee exposure'*levels are well within safe limits. CC* 000002443 10090032 BFG37247 Paul fetzer December 30, 1980 Page 2 COPY Based on the results of this study, 1 would make the following reconrnendat i ons : 1. Ve should continue to use the OVH for measuring personnel exposures while being aware of its limitations. 2. If you have the personnel to do more research next suniner, I would suggest you consider a "field" study to verify these laboratory results. Perhaps a personnel sampling scheme of several shortened periods (i.e., 4 two-hour periods) could be devised and these results compared to current eight-hour re sults to see if there is a true difference or significant under estimation with the eight-hour sampling scheme. 3. With the continuing wide-spread use of passive dosimeters in the industry, I feel these.results are. important to share. I feel we should give consideration to reporting or publishing these results through an appropriate scientific medium. Thomas G. Grume,..;., dfb cc: J. J. Hall J. A. DeBernardi CCR 000002"' BFG37248 r