A commonly used animal drug is being suspended from sale in response to new U.S. Food and Drug Administration data showing it increases arsenic levels in chicken livers.
Though public health and industry experts stress that the levels of arsenic found in the new FDA study were very low, and that eating poultry treated with the drug, known as Roxarsone, “does not pose a health risk,” Alpharma, a subsidiary of drug giant Pfizer, said Wednesday it is voluntarily halting the sale of the drug, which has been used by poultry producers to promote growth and combat parasites since the 1940s.
Roxarsone, which contains arsenic, a known carcinogen, is also approved for use in swine and turkey production and is known to improve coloration in meat products. FDA officials told reporters Wednesday that the move to halt the sale of the drug is aimed at reducing unnecessary exposure, not prompted by immediate concern over human health impact.
“The levels that we’ve detected in the study FDA conducted are very low and even low with respect to other levels,” said Dr. Bill Flynn, the deputy director for Science Policy at FDA’s Center for Veterinary Medicine, noting that arsenic can be present in air, water, and the environment. The concern is over whether the organic arsenic present in Roxarsone could be transforming into the more-toxic inorganic arsenic.
The new FDA study, the results of which Pfizer was made aware of in early May, detected increased levels of inorganic arsenic in the livers of chickens treated with the Roxarsone. The new data raised concerns of a “very low but completely avoidable exposure to a carcinogen,” said Michael Taylor, FDA deputy commissioner for foods on a call with reporters. “We are pleased to announce that the company is cooperating with us to protect the public health.”
Officials at FDA say they don’t know how widely Roxarsone is used in domestic poultry production — its use has been on the decline in recent years as consumer groups have drawn attention to the issue — but one official estimated upwards of 90 percent of the drug is used in chickens. A spokesperson for Pfizer said the company does not disclose sales data, but around 15 countries have approved the drug for use in poultry production.
“It’s fairly broadly used in the broiler industry, but we do not have specific information regarding the actual numbers of chickens or percent of chickens that actually receive the drug,” said Dr. Flynn in media briefing, referring to domestic production.
Despite the new findings, one other arsenic-based product remains on the market for food animal production: Nitarsone, which also is marketed by Pfizer, but is only approved for use in poultry. FDA officials say they are “in discussions” with the company about the product.
Pfizer is giving the animal agriculture sector 30 days to find alternatives and transition away from Roxarsone before suspending its sale — and the move might not be permanent — but Flynn told reporters: “We’ve gotten a clear assurance from Pfizer that they will not return the product to the market unless they’ve first addressed all of FDA’s concerns.”
It is unclear whether FDA scientists are examining other popular animal drugs for residue concerns. When asked about other studies in the works, Flynn noted that the agency was responding to “a very particular concern” that was sparked by a growing body of scientific literature looking at arsenicals in animal agriculture.
Consumer groups lauded the move to suspend the drug.
“Inorganic arsenic is cancer-causing and action on this drug is long overdue,” said Michael Hansen, a senior scientist at Consumers Union, the publisher of Consumer Reports. Consumers Union has long been opposed to the use of the drug in food animals. In 2005, Consumer Reports found that arsenic was present in grocery-store chicken livers from many conventionally raised chickens.
“Arsenic in chicken production poses a risk not only to human health, but to the environment,” added Hansen. “Arsenic can end up in the manure from chicken coops and this is spread on agricultural land as fertilizer. Chicken coop floor waste is also routinely swept up and recycled as feed to cows on large-scale feedlots. We need to get arsenic out of food production altogether.”
The poultry industry has long argued that the drug is important for animal health. John Starkey, president of the U.S. Poultry and Egg Association, told Food Safety News last year that it “enhances animal welfare, increases sustainability of production, and can lead to improved food safety.”
“There are well-esstablished and well-respected procedures in place at FDA to ensure the safety and efficacy of the use of products such as roxarsone in animal feeds,” said Starkey.
In 2009, the Center for Food Safety and Institute of Agriculture and Trade Policy, and a half dozen other consumer and agriculture groups, petitioned FDA to ban the drug. In April, Rep. Steven Israel (D-NY) reintroduced a bill to do the same.