Document g2Vj76BLw505pnK7ZQqx97r49

we - 6f''*'3 MccJZ -"tho. bgnacnc M^irctaa^rofframs of-the APT and the C!W* To this purpose, n small vrt>Yj&n|Tgroup of toxicologists (rsprssonting the CMA Benzene TRTG and/or the API Toxicology Committee) was established and charged with the responsibility to "rethink" to CMA and API research programs and to develop a technically sound (yet cost-effective) experimental approach*. Six specific research objectives were delineated. 1. Can we create a "dose-response curve "for the following piirnnuiLors (hematologic, cytogenetic, anatomical changes)? 2. Con wo demonstrate an "effect level" at low concentrations of benzene vapor? 3. Can wc identify a more sensitive Indicator of toxic effect? . 4. Is .there an increased susceptibility to toxicity on repeated (intermittent) exposures? 5. Are there permanent effects from a single, high exposure (puiso)? 'i. Arc there permanent effects from an occasional high exposure (repeated pulse)? Ihe studv de .ic.as presented here, address these research objecr 1 ves. It should he cnph.islzej that these do sinus are presented`as an indication of research direction only, and should not he construed as final protocols. 00 067933 CONFIDENTIAL 02070 YZ0080914 I BliiWNt; FIVE-DAY ACUTE UF.N.1EKE INHALATION STl'.QY I \ Purport: Dr. J. Dornor (API consultant) has been asked to consider varlomt b3tBJS-C3t*boratWfy tests that'mny`be useful (JttW practical) for monitoring benzene toxicity (e.g., 6-ALA, red cell hemolysis, serum enzymes, leukocyte alkaline phosphatase, etc.). He will recommend several tests for API/CMA consideration. The purpose of five-day study described below Is 1) to confirm that these parameters are In fact mcasureahle In the rat and mouse, 2) to give a preliminary indication of their responsiveness to toxic benzene exposure, and 3) to validate the contract laboratory's ability to perform these tests. Ou the basis of these observations, one or more of these parameters wjll be tested further. Exposure Concentrations: Control and 2000 ppm Exposure Duration: 6 hours/day for 5 days Animals; S male and S female rats and mice/group. Clinical Observations: Pre-exposure and after fifth day of exposure. Sacrifice: Ac termination, the animals will be sacrificed and nocrop3led grossly, Tissues will be saved for.possible hlstopathologlcal examination at a later dace. I * D0 067934 f.ONFTDFNTTAl YZ0080915 np.N/.KNi: NINETY-DAY SUUCHR0N1C STUDY \ ..Purpose: The purpose of tho 90-day oubchrcmicRtudy la 1) to identify the mdsa'-saneAtSVe parameter Indicative of a toxic effect due to bcitzcnu exposure, 2) to provide a general Indication of the level of benzene exposure necessary for this toxic change to occur, anJ 3) to define the length of time necessary to develop such a toxic change. Such information will be used In selecting the exposure levels and exposure intervals for chronic studios. Exposure Concentration.: Control and 4 levels Exposure Duration: 6 hours/day, 5 dnys/weuk, for 13 weeks. Animals: 5 mile and 5 femnln rats and mire per group will he sacrificed at each observation point to provide blood, tissues, etc. for nil clinical observations except cytogenetic, oval.uut Lon. A sepnraLo group of 5 ialo. and 5 female rats and mice will be pulsed with colcemld one-hour before sacrifice for Cytogenetic analysis at each observation point. Clinical Observations: The following will be .noted at days 0, 1, 15, 30, 60, and 90. - Hematological Evaluation (eg, RBC count, WBC count, differential, platelets, hematocrit, mean corpuscular volume) - Clinical Chemistries - Consultant's battery (selection based on consultant's recommendations and results of the 5-day study) - Bone marrow chromosome assay (using separate group of animals pretreated with colcemld). Sacrifice: At each observation point, all animals not pretreated with colcemld will be examined by gross necropsy. Tissues from these animals will be saved for possible future hlstopathology. At the terminal sacrifice, tissues of the high exposure level group will be ..prepared for hlstopathology. If possible signs of benzene-induced toxicity ere noted at`-Chls level, the CMA may request a complete hlstopathologleel survey of all tissues. At each observation point, the bone marrow of colccmid-treated animals will be prepared to a suitable stage end will be saved for possible future cytogenetic analysis. At the terminal sacrifice, the bone marrow of the high exposure level group will be prepared and screened for cytogenetic changes. If positive signs of benzene-induced toxicity are noted at this level, the CMA may request a complete chromosomal analyses of all other bone marrow preparations. ^O 067935 OONFTDFNT TA! YZ0080916 KKN'/KNK two-year chronic study I \ i Purpose: Because of NYU's finding of one case of chronic myelogenous r" -- leuksmiar*^*s Mail .ae a suggestive* trend for RBS- end lymphocytes in iiCt' Sk^tTaed to 100 ppm, an evaluation of the toxic effects of low level benzene exposure is proposed,. Exposure Concentrations; Control end 4 exposure levels Exposure Duration: 6 hours/day, 5 days/week for 24 months Animals: 10 male and 10 female rats and mlce/intcrim sacrifice group 5 male and 5 female rats and mice/interlm sacrifice group (cytogenetics only) 50 male and 50 female rats and mice/terminal sacrifice group 5 ra^le and 5 female rats and mice/terminal sacrifice group (cytogenetics only) Clinical Observations: Cytogenetic, hematologic, and/or chemical observations (selected on basis of 90-day`atudy results) will be made at 0, 6, 12, 18, and 24 months. Terminal Sacrifice: All animals will bo sacrificed at 24 months. A complete necropsy will be performed and a complete set of tissues will be saved from all animals except those used in cytogenetics. High exposure level animal tissues and chromosomes will be evaluated for histopathology. The CMA may request a.complete histological survey of all tissues at a later date. rl 00 067936 CONFTDFNTXAl YZ0080917 TWO-YEAR INTERMITTENT STUDY IIMN/KNK \ ?ur.pOe: To dgtormjno If. there is a potential for ^increased susceptibility ter-trroxte-^esponse after benzene Interraittont `exposures. Exposure Concentration: Control and one level (to be determined on baslx of 90-day subchronic study). Exposure Duration: The time Interval (X) for exposure end clinical observation;) will be determined using data from the 90--day subchronic study* Exposure Cycle 1 will begin with exposures at day 0 and will continue to day X on a 6 hours/day, 5 daya/week schedule. Animals will then be held to six months without exposure; this period may be extended if the mean of the treated animals do not show recovery to within 1 S.D. of the control mean. * Exposure Cycle 2 will begin at 6 months (or at the time when animals have ' recovered to within 1 S.D. of the control.mean) and will continue until day 6 months + X. Animals will then be held to one year (or until ehe vecovti'y); "M* * animals will be sacrificed. Animals: 25 male and 25 female'rats and mice/group. 5 male and 5 female rats and mice/group (cytogenetics only). Clinical Observations: The "most sensitive Index" of benzene toxicity (as determined in the 90-day subchronic study) and cytogenetic evaluations will be performed at days 0, (2/3 X), (X), monthly to 6 months (or recovery). 6 months, (6 months + 2/3 X ), (6 months + X), monthly to 12 months (or recovery). * TfcTGr approve bond** Vcr IaM A*W "tL Ho-fceeJ ti p*otoc-*f. 00 067937 CONFIDFNTlAL YZ0080918 Chronic Two-Year (24-Month) Single High level Exposure \ -Fvcp.ose: To determine the lone-Lerm toxicological effects of single high exposure etHTcnzene as compared to longer term TdV-lovel exposure offacts. Exposure Concentration: LC,fl for benzene for prescribed time, preferably 4-6 hours. Exposure Duration: One exposure of from 4-6 hours and 24 months of no exposure. Animals: 125 male and 125 femAle rats and mlce/ternlnal sacrifice treatod group 50 male and 50 female rats and mice/terminal sacrifice control group 10 male and 10 female rats and ralce/sacrifice group ("most sensitive indicator") 5 irfale and 5 female rats and mice/sacrifice group (cytogenetics only). Clinical Observations: At 0,7 and 14 days, and 12 and 24 months, interim ` clinical observations will consist of the ."most sensitive indicator" for benzene exposure and cytogenetics (preparation only). Five male and five female `animals will be run for each sacrifice period to provide animals for cytogenetics. Ten male and 10 female animals will bo run to provide for determination of the "most sensitive" benzene exposure parameter plus necropsy and tissue storage at the.interim sacrifices. Sacrifice: All surviving animals will be terminated at 24 months. A gross necropsy will be performed, and tlssuee will be saved and histopathologlcnlly evaluated. The sponsor may request ell other tissues to be evaluated at e later date. Cytogenetic analyaie will ba done on animals from the high exposure group. Others will be done if positive results ere fdtind. DO 067938 CONFIDENTIAL YZ0080919 \ .Purpose: To^Jotecmlne toxicological effects olMiigh level, abort tfurairtoii-^irposurcs to benzene. Exposure Concentration: 1000 ppm benzene and a negative control Exposure Duration: 2 houre/day, two days/week for 24 months Animals: SO male and 50 female rats and mice/terminal sacrifice group 10 male and 10 female rats and mice/interim sacrifice group 5 male and 5 female rata and mlee/intcrlm sacrifice group (cytogenetics only). Clinical Observations: In all animals, at 0, 6, 12, 18 and 24 months the "most sensitive' index" of benzene toxicity as determined in the 90-day study and cytogenetics. Bone marrow preparations suitable for cytogenetic assays Will be made and stored for 5 male and 5 female animals wfilch will be separate from the main animal population in the study. These animals will not be necropsicd, and tissues will not be saved. Sacrifices: At all interim observation periods, 10 male* and 10 female animals (which will not be part of the mian population of the study) will be sacrificed and necropsled; tissues will be saved. At the 24 month sacrifice, complete necropsies will be done and tissues will be saved. Hlstopathology will be done on all terminal tissues with the possibility that the sponsor may request that the interim aaorifice tissues also be evaluat'd. Cytogenetic analysis will be done on animals from the terminal sacrifice. "Further analysis will be done if positive results are found. ' TRTGr *^tMrovl -fclu t **fc/**** ]^ua DO conf YZ0080920 4 4 DOW CHEMICAL U.S.A TEXAS DIVtWOM miVWT. TEXAS T7S41 June 14, 1978 Mr. Steven Williams Office of The General Counsel American Petroleum Institute 2101 L Street N. W. Washington) D. C. 20037 Dear Mr. Williams: BENZENE CYTOGENETIC STUDY - PICCIANO Enclosed are four versions of the Dow benzene cytogenetic study: "A", "B", and "C" by D. J. Picciano, et. al, and "D" by D. J. Kilian and R. L. Daniel. The cytogenetic data are the same, i.e., they are from a 52 employee population at our Freeport, Texas Benzene and Ethyl benzene-A plants. The "D" version was submitted by Dow to EPA and to NIOSH and contains our best assessment of the employee exposure history. ' we do not know how many of these were turned over to Rachel Scott or to OSHA. Since Picciano deleted the last sentence from paragraph 2, page 3 which states "at least one positive UEP test indicating a possible exposure to benzene greater than 25 ppm" from versions "B* and "C", it is unlikely that Scott in working from version "A" or that OSHA would submit version "A" in evidence. You should be aware of the fact that Drs. Jacobson, Legator, and Wharton had no reason to question the completeness of the environmental exposure section of Picciano*s study. Therefore, their comments were mostly laudatory. We will be glad to attempt to answer any questions that your review of these documents may raise. Yours very truly bbs Attachments (4) R. L. Daniel Environmental Health Services cct Andrew T.A. Macdonald Wilmer, Cutler 6 Pickering 1666 K St., N.W. Washington, _D.C,.,,_2000$_____ AN PERATINQ UNIT OP THE OOW CHEMICAL COMPANY 00 067940 CONFIDFNTT Al YZ0003057