Alpharma, a subsidiary of Pfizer Inc. will suspend sales in 30 days of 3-Nitro (Roxarsone), used by poultry producers since the 1940s.
An FDA study of 100 broiler chickens detected inorganic arsenic, a known carcinogen, in higher levels in the livers of those treated with 3-Nitro.
Scientists report that organic arsenic, less toxic and present in 3-Nitro could transform into inorganic arsenic.
Arsenic occurs naturally in the environment and is found in water, air, soil and food.
The company is working with the FDA, examining scientific data and use of 3-Nitro in animals.