Zoetis Animal Health, maker of Histostat, asked the government to withdraw all feed-additive uses by the end of this year. It stopped selling the product this fall.
Nitarsone has held approval for the prevention of blackhead disease (histomoniasis) in turkeys and chickens, but was mostly used in turkey rations.
Arsenic is in the environment as a naturally occurring substance or as a contaminant and is found in water, air, soil, and food.
Published scientific reports have indicated that organic arsenic, the less toxic form of arsenic present in the arsenic-based animal drugs, could transform into inorganic arsenic, a known carcinogen.