Pets may not be the only organisms endangered by some food additives. An arsenic-based additive used in chicken feed may pose health risks to humans who eat meat from chickens that are raised on the feed, according to an article in the April 9 issue of Chemical & Engineering News, the weekly news magazine of the American Chemical Society.

Roxarsone, the most common arsenic-based additive used in chicken feed, is used to promote growth, kill parasites and improve pigmentation of chicken meat. In its original form, roxarsone is relatively benign. But under certain anaerobic conditions, within live chickens and on farm land, the compound is converted into more toxic forms of inorganic arsenic. Arsenic has been linked to bladder, lung, skin, kidney and colon cancer, while low-level exposures can lead to partial paralysis and diabetes, the article notes.

Use of roxarsone has become a topic of increasing controversy. A growing number of food suppliers have stopped using the compound, including the nation's largest poultry producer, Tyson Foods, according to the article. Still, about 70 percent of the 9 billion broiler chickens produced annually in the U.S. are fed a diet containing roxarsone, the article points out.

Complicating the issue is the fact that no one knows the exact amount of arsenic found in chicken meat or ingested by consumers who frequently eat chicken. "Neither the Food and Drug Administration nor the Department of Agriculture has actually measured the level of arsenic in the poultry meat that most people consume," according to the article.

The National Chicken Council, a trade association that represents the U.S. chicken industry, claims there is "no reason to believe there are any human health hazards" associated with the use of roxarsone.