Opinion: FDA needs to follow through on its plan to ban carbadox in animal feed

An antibiotic known as carbadox can damage genes and cause cancer. The European Union, Canada, Australia, and the United Kingdom have banned its use for years. So why does the U.S. Food and Drug Administration allow pork producers to keep using it?

Carbadox is fed to more than half of the pigs raised in the U.S. for food. It promotes growth and controls gut infections. But it poses significant safety risks to consumers who unknowingly consume carbadox residues when eating pork. It can also harm farm workers who are exposed to the drug when mixing feed or working in buildings where carbadox is used.

In 2016, when Robert Califf was first head of the FDA, the agency initiated steps to withdraw approval of carbadox. But vigorous pushback from industry and perpetual stalling by the agency have stagnated efforts to ban its use. The lack of a Senate-confirmed FDA commissioner during the first year of the Biden administration also likely contributed to the delay.


In its 2016 proposal to withdraw approval of carbadox, the FDA cited findings from the international Codex Committee on Residues of Veterinary Drugs in Foods that there is “no safe level of residues” of the drug. The FDA also said that continued approval of carbadox would expose humans to “concentrations of residues of carcinogenic concern that are approximately 30 times higher” than what would be considered safe.

Research conducted since 1998, when the method for detecting carbadox residues was approved, shows that they persist longer than was previously believed, indicating that the way these residues are measured is inadequate. Without a sensitive and valid detection method, the FDA is unable to ensure that residue levels are low enough to mitigate consumers’ carbadox-related risks. In response to the new research, the FDA announced in 2020 its intent to withdraw the existing residue-detection method. Since drugs that cause cancer in animals raised for food can be used only if an approved residue detection method exists, withdrawing the detection method acts as a de facto ban on carbadox use.


The FDA held a hearing in March 2022 to gather evidence on possible new residue detection methods. During the hearing, the agency indicated what information would be needed to develop an adequate method to protect consumers. Phibro Animal Health Corporation, the company that makes carbadox, failed to present the necessary safety data. Instead, it presented data it had already shared with FDA in 2016 and insisted that the drug was safe to use.

Food Animal Concerns Trust, the organization I direct, called on the FDA to ban the drug, citing the significant public health risks associated with its use. Representatives of the pork industry argued during the hearing that the drug was a necessity for animal health. The FDA has extended the comment period on residue detection methods until June 10.

It’s past time for a change on carbadox and other drugs used in growing animals for food that pose public health risks like causing cancer. Antibiotic resistance and the resulting spread of difficult-to-treat superbugs is another issue. Two-thirds of medically important antibiotics sold in the U.S. are used to raise animals for food.

Over the last 50 years, the FDA has failed in its mission to protect people from potentially dangerous drugs used in raising cows, pigs, chickens, and other animals for food. Instead of catering to the drug and animal agriculture lobbies, the FDA needs to protect human and animal health.

Now that Califf is once again leading the FDA, I hope he will reinvigorate the much-needed steps that were started during his previous tenure as commissioner and do his part to protect public health.

Harry Rhodes is the executive director of Food Animal Concerns Trust, a not-for-profit organization focused on ensuring that people have access to safe and humanely produced food.

Source: STAT