This has been somewhat controversial for a while, but now there is some official test data and it looks like this is the last straw for Roxarsone: http://abcnews.go.com/Business/wireStory?id=13793945 "The Food and Drug Administration says some chicken meat may contain small amounts of arsenic, though the agency is stressing that the amount is too tiny to be dangerous to people who eat it. The FDA said Wednesday that a new study developed by the agency shows that an ingredient in chicken feed that contains arsenic, called Roxarsone, may make its way into parts of the bird that are eaten. Previous studies have indicated that the arsenic was eliminated with chicken waste. Pfizer Inc., which makes the feed ingredient, said Wednesday that it will pull it off the market in the United States. Had the company not stopped sales, the FDA could have eventually banned the product since it contains a known carcinogen." Good riddance. Now, what is the fate of all the arsenic that is already present in the millions of tons of chicken manure, much of which has already been spread on farmland? How much of it will convert to the inorganic form (carcinogenic)? How much of that will get taken up by food crops? What a mess.