Roxarsone is an organoarsenic compound that has been used in poultry production and to a lesser extent in Swine production as a feed additive to increase weight gain, for greater feed efficiency, to improve pigmentation, and as a coccidiostat. Until June 2011, it was approved for use in the United States, Canada, Australia, and 12 other countries. It is no longer approved for use in most jurisdictions.
Roxarsone has been banned in the European Union since 1999. Its use in the United States was voluntarily ended by the manufacturers in June 2011, and it has been illegal since 2013. Its use was suspended in Malaysia in June 2011. It was banned in Canada in August 2011. In Australia, its use was discontinued in 2012.
Roxarsone was marketed as 3-Nitro by Zoetis, a former subsidiary of Pfizer now a publicly traded company. In 2006, approximately one million kilograms of roxarsone were produced in the U.S.
A 2013 market basket study conducted in the United States linked the use of roxarsone and other arsenical feed additives to increased levels of inorganic arsenic in chicken breast meat. The study was performed on chickens raised prior to the voluntary withdrawal of roxarsone from the market by its manufacturer. Breast meat from chickens exposed to arsenical feed additives contained inorganic arsenic at the level of about two parts per billion. Breast meat from chickens raised in farms with a policy not to use arsenical feed additives contained inorganic arsenic at the level of 0.7 parts per billion. Organic chickens are not exposed to arsenical feed additives and contained about half a part per billion.
Federal standards at the time permitted concentrations of 500 parts per billion of total arsenic, but were established before 1963 and did not differentiate between organic arsenic and its highly toxic inorganic variety. In February 2011 the FDA's Center for Veterinary Medicine recommended inorganic arsenic in chicken not exceed 1 part per billion, then revised the statement to remove language suggesting a safe concentration, noting: "any new animal drug that contributes to the overall inorganic arsenic burden is of potential concern."
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