Document 82r725vOrZYm2ZjyqppbgjOGe

3M MEDICAL DEPARTMENT TOXICOLOGY SERVICES cc: John Butenhoff From: MarvCase Subject: Covance Study 6329-222 Date: 27 July 1998 On 22 July 1998 when I was at Covance Madison, I reviewed the microscopic liver tissue sections of the monkeys on the 4-week oral rangefinder study of PFOS (Covance study 6329-222). There was no evidence o f compound-related effects in the liver even in the high dose animals. Our toxicology consultants had asked the question whether the high dose monkeys had any evidence o f liver necrosis or any other microscopic evidence adverse liver effects. The answer is negative.