WASHINGTON - The Food and Drug Administration said Wednesday that 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 showed that an ingredient in chicken feed that contained arsenic, called Roxarsone, may make its way into parts of the bird that are eaten. Past studies have shown the arsenic was eliminated with chicken waste.

Pfizer Inc., which makes the feed ingredient, said Wednesday that it would 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.

Many poultry producers have already stopped feeding their birds the ingredient, which has been used since the 1940s to kill parasites and promote growth.

The FDA said that people should not stop eating chicken that may have been fed the drug.

Pfizer said in a statement that a subsidiary, Alpharma L.L.C., was suspending sales next month because of the FDA findings. The company said it was waiting a month so producers had time to transition their birds off the drug. The ingredient will also be pulled off the market for swine and turkeys, though the FDA studied only chickens.

In the study of 100 chickens, the FDA found that chickens that had eaten the Roxarsone had higher levels of inorganic arsenic - as opposed to organic arsenic, which is naturally occurring - in their livers than chickens that had not eaten the Roxarsone. Inorganic arsenic is more toxic than the naturally occurring form.

Roxarsone has long been a concern for environmental and consumer groups especially in areas with high chicken production.