Document e5J4rX5X9eD4j52L1kq69yYzp

CC1 iAndry REEtfiftMING aprWL ,, j />. IjJ' ' (` ->, ' Iff* Co-6 Coin Laundry Association Intomational Fabrieart Institute Institute of Industrial Launderers Nat'l Assn, of Institutional Laundry Manager* Toxtila Cara AAlIlIiaI.dJ Tradas AAs-s*_n. ' * Taxtila Rantal Sarwicas Association of Amarica :Contact: wK1W-SaiPA'llJJ 301/622-1900 NEWS RELEASE^ v A 1985 EPA Advisory Board Releases Findings on Perc Cancer Issue /n a recently released letter sent to EPA Administrator William Ruckelshaus, EPA's independent Stienee Advisory Board (SAB) announced its finding that! "...insufficient evidence exists to classify (perc) as a probable carcinogen for humans'' and that there is only "...limited evidence of carcinogenicity for animals.'' The Science Advisory Board stated that it found deficiencies in the National Cancer Institute (NCI) tests of perc and that the mouse liver tumors in those tests may be due to peculiarities in the metabolizing of perc i unique to the particular mouse strain used. They also slated that the population studies of drycleaning plant workers do not substantiate the hypothesis that perc is carcinogenic to humans. For these reasons, the SAB has found that there is insufficient evidence to classify perc as a Class B "probable" human carcinogen. Under EPA's new classification system, this would place perc in class C, a "possible" carcinogen. In general, class C is for those chemicals where a single test has shown positive results in a single animal species: this is the lowest class that perc could be put into. The Science Advisory Board is made up of consulting scientists and doctors who do not work for EPA and whose function is to provide an unbiased review of cancer information and new scientific policies developed by EPA. Their findings and recommendations are given to the EPA Administrator for review as to their use in developing the basis for proposed regulations. ; Following this review, the Administrator will normally transmit the SAB's findings to each of EPA's major branches (for example, the Air office, the Water office, 'and the Solid Waste office) to use in determining which, if any, regulations would be appropriate. Of particular concern to LCC at this time i^ the proposed "recommended level" of zero for perc in drinkirtg water. This recommendation, from EPA's Drinking Water Office, is based on an assumption of probable carcinogenicity, whereas the SAB findings support LCC's formal testimony' to EPA that such a designation is unwarranted. The Position of the Laundry Geaning Council 1 The position of the LCC on the perc cancer issue is as follows: "Perc was found to cause liver cancer in | mice in the original test done by NCI, although many questions have been raised about the validity of those tests. While we believe that the best evidence will eventually snow that perc is not a human carcinogen, it cannot be stated 'with absolute certainty that it is not. For this reason, LCC believes that it is prudent to continue to minimize exposures to perc as much as possible. LCC continues to seek the best possible scientific information on perc to resolve this issue, and opposes regulation of perc at this time as a probable human carcinogen pending the completion of properly run scientific testing." In short, the original cancer test of perc jtave positive results in mice but has been strongly criticized because of testing problems. While we feel that perc will belfound not to be a human carcinogen, a final answer will not be known until proper tests are completed. Until that time, LCC believes that the industry should be aware of the original positive results and minimize exposures. LCC's position on the perc cancer issue is reinforced by the findings of the Science Advisory Board. The Status of Current Testing of Perc The second test of perc by gavage (force-feeding) in mice at four dose levels has been completed and the report is being written. LCC's understanding is that the mice (the same strain as used in the original NCI test) showed increased levels of liver cancer at the two higher doses and no cancer at the two lower doses. These results can be interpreted in two ways: 1) The validity of the mouse liver tumors in the first NCI test have now been confirmed, or 2) Liver cancer occurs in this mouse type only at high, toxic dose levels, because of a particular susceptibility in the strain which does not translate to human exposures. The new inhalation tests have recently been completed and the data is just beginning to be studied by the National Toxicology Program. It is too early to tell what the results of those tests might be, but the report should be available within approximately one year. At that point, LCC hopes that the tests will be found to have been run properly and that clear-cut answers are available. LCC Summary of Specific SAB Findings on Perchloroethylene In their two-page cover letter and seven-page "key findings and conclusions," the Science Advisory Board made some of the following specific comments: "The critical scientific issue addressed by the Committee in its review was the evidence for the carcinogencity of perchloroethylene. Resolution of this issue is made exceedingly difficult due to the presence of liver tumors in the test animals....The scientific community is not certain about the relevance of the animal data for perchloroethylene to human carcinogenicity because the validity of the mouse liver bioassay is uncertain....As a result, an authoritative scientific opinion concerning the carcinogenicity of (perc) cannot be provided at this time by the Committee." "The majority of Committee members advise that these data should be regarded as limited evidence of carcinogenicity for animals, and that this evidence is insufficient to conclude that perchloroethylene is a possible human carcinogen." "...the Committee finds no evidence to show that perchloroethylene causes gene mutations or chromosomal aberrations." "(EPA) scientists stated that the document would be modified to indicate that hepatotoxicity (liver toxicity) is not an end point of concern below 100 parts per million (ppm) exposure." Finally, EPA's Carcinogen Assessment Group calculates "unit risk estimates" to estimate the maximum probable cancer risk for a chemical, assuming that it is indeed a carcinogen in the first place. With respect to perc, the SAB stated "...the evidence for the carcinogenicity of perchloroethy lene is too weak to support a formal calculation of a unit risk estimate on solely scientific grounds." Sl^