At the risk of getting a brick thrown at my head, fipronil is classified as a "possible human carcinogen" due to increased rates of thryoid cancer in rats fed fipronil. There are very good reasons that potentially toxic chemicals are tested on rats instead of dogs and humans--I don't think that I need to go into them--and this is a standard procedure for determining carcinogenicity. You simply don't release potentially toxic medicines without testing them on lab animals first. |