Document K67gZNYO4dK3R2jo2q6YDxBMN

July 18, 1975 Dr. J.C, Calondra Industrial BIO-TEST Laboratories 1810 Frontage Rd. Northbrook, 111, 60062 \ A / Va y ret AROCLOR 2-year Rat Feeding Studies Dear Joe t The attached tabjje-nsxtmmarizes a comparison of the 3 revised AROCLOR reports ((12^ 1254, 1260). In 2 instances, the previous conclusion of "slightly tumorigenic" was changed to "does nob appear to u eaxoinogouic''. The latter phrase is preferable, Mav we request that the AROCLOR 1254 report bo amended to say 'does nob appear to be carcinogenic". The number of hepatomas reported for AROCLORS 1260 and 1242 have been interchanged. This appears to have arisen from con fusion regarding the numbering of the animals. The original reports show tumors In animals with numbers in the 100-300 range for AROCLOR 1260 and in the 500 to 800 range for AROCLOR 1242. This leads me to conclude that the numbering scheme shown in the second set of reports is correct. With AROCLOR 1254 confusion is compounded. The original report showed tumors in animals with numbers in the units to teens, but the revised report: shows animal numbers ranging from 4o to 1000. Can this be straightened out? I was unable to reconcile the differences in the animal numbers between the first supplemental report and the original reports, I had inquired as to the changes in the numbers. As I recall", I was told that the sections had been renumbered when the new slides were made and that a key relating to the sets of numbers DSW 035046 STLCOPCB4018873 Dr. J.C. Calandra July 18, 1975 Page ~ 2 ~ would be supplied. This has not been done. It may not be necessary for AROCLORS 1260 and 1242, but AROCLOR 1254 remains unresolved. Insofar as I can see, the remainder of the reports appear acceptable. Kindest personal regards. Sincerely, George J. Levinskas, PhD Mgr., Environmental Assessment and Toxicology /bkp att, cc: Dr. George Roush, Jr., M.D. DSW 035047 STLCOPCB4018874 Product Supplemental Report (mailed) AROCIiOR 126,0 conclusion slightly turaorigenie hepatomas 3 range of test animal nos: P- 9 p. 10 p. 11 p. 12 600 to 800 1000 series 70 to 100 500 to 600 600 to 700 700 series Supplemental Report #2 (JCC delivered) does not appear carcinogenic 7 100 to 300 800 to 000 lotto 40 80 to 200 200 to 300 200 to 300 AROCLOR 1254 conclusion hepatomas slightly turaorigenie 6 slightly tumorigenlc 6 AROCLOR 1242 conclusion slightly turaorigenie does not appear carcinogenic hepatomas range of test animal nos. 73 as In report #2 as in report #1 for AROCLOR 1260 AROCLOR 1260 OSW 035048 STLCOPCB4018875