However, FDA officials stress the levels of inorganic arsenic detected were very low and that continuing to eat chicken as 3-Nitro is suspended from the market does not pose a health risk.
"FDA detected increased levels of inorganic arsenic in the livers of chickens treated with 3-Nitro, raising concerns of a very low but completely avoidable exposure to a carcinogen," said Michael Taylor, FDA deputy commissioner for foods. "We are pleased to announce that the company is cooperating with us to protect the public health."
Published scientific reports indicate that organic arsenic, a less toxic form of arsenic and the form present in 3-Nitro, could transform into inorganic arsenic. In response, scientists from the FDA's Center for Veterinary Medicine and the Center for Food Safety and Applied Nutrition developed an analytical method capable of detecting very low levels of inorganic arsenic in edible tissue.
Using the new method, FDA scientists recently found the levels of inorganic arsenic in the livers of chickens treated with 3-Nitro were increased relative to levels in the livers of the untreated control chickens.
Alpharma decided to voluntarily suspend sale of 3-Nitro and to facilitate an orderly process for suspending use of the product in the US. The company's plan provides for continued sales of 3-Nitro for 30 days from June 8. The company said allowing sales for this period will provide time for animal producers to transition to other treatment strategies and will help ensure that animal health and welfare needs are met.
The company is also working with the FDA to examine all relevant scientific data regarding the use of 3-Nitro in animals.
3-Nitro became the first arsenic-containing new animal drug product approved by the FDA in 1944. It is used primarily in broiler chickens. Combined with other animal drugs, 3-Nitro has been used by some in the poultry industry to help control coccidiosis, a parasitic disease that affects the intestinal tracts of animals. It has also been used for weight gain, feed efficiency and improved pigmentation.
FDA said the agency has consulted with the US Department of Agriculture and is working with Alpharma to minimize the impact on the animal agriculture industry as 3-Nitro is suspended from the market.