Three of four arsenic drugs used in animal feed have been banned by the U.S. Food and Drug Administration.

Yes, that's right — that means that up until now, arsenic was used in animal feed.

The drugs — roxarsone, carbarsone and arsanilic acid — were added to feed for chicken, turkeys and pigs to prevent disease and promote growth and a “healthy” pink hue. (Unfortunately arsenic does not kill salmonella.) However, recent studies showed levels of arsenic in chicken exceeded amounts that occur naturally, The New York Times reported. Meaning that the arsenic in the feed was doing more than just its job. Wouldn't ya know it was making its way into the animals' tissues, thence into your mouth, your tummy and your tissues.

The Center for Food Safety and several other advocacy groups filed a petition with the FDA four years ago seeking to ban the four drugs in animal feed. Recently the CFS filed a lawsuit to try to force the FDA to respond, which seems to have worked.

The FDA's move calls for the immediate withdrawal of the vast majority of arsenic-containing compounds used as feed additives for chickens, turkeys and hogs. Of the 101 drug approvals for arsenic-based animal drugs, 98 will be withdrawn, according to the CFS.

The fourth drug, nitarsone, is the only known treatment for blackhead (histomoniasis), a disease that can kill turkeys, so for now it can still be used. The FDA said it will continue to study the effects of nitarsone, the Times said, and will make a final decision on whether or not to pull it from the food supply in 2014.

Interestingly, the FDA said it is rescinding approval for the drugs not in response to the petition, but at the request of the companies that market them.

The companies, Zoetis and Fleming Labs, already had largely withdrawn the drugs from the market after the recent studies showing high levels of arsenic in chicken. Zoetis withdrew roxarsone from the market voluntarily two years ago.

“The withdrawal of these harmful feed additives is a major victory for consumers and the health of our food system. It is unfortunate that legal pressure from outside groups was necessary to spur action by FDA, yet in the end, we are pleased that FDA listened to our scientific objections and is now working to rid arsenic from our meat supply,” said Paige Tomaselli, senior attorney with the Center for Food Safety.

A 2006 Institute for Agriculture and Trade Policy report estimated that more than 70 percent of all 8.7 billion chickens produced in the U.S. for meat each year are fed arsenic. And, Americans eat a lot of chicken. From 1965 to 2013, consumption of chicken jumped from 33.7 pounds to 83.1 pounds per person per year: a 250% increase.

In the FDA's response (four years later) to the CFS petition, the agency acknowledged that recent scientific reports on arsenical compounds in animal feed challenged previous assumptions of safety. In particular, concern arose over the ability of organic arsenic (which is non-carcinogenic) to transform into inorganic arsenic (known to be carcinogenic) in the environment or animal tissue.

The FDA asked the additive manufacturers to provide additional information related to whether inorganic arsenic can be detected in the edible tissues of animals administered their particular arsenic-based animal drugs. After receiving the FDA's letter, Zoetis cried uncle and requested that the FDA withdraw approval of roxarsone and carbarsone on September 19. Fleming Laboratories, Inc. similarly rolled over, requesting that the FDA withdrawal approval of arsanilic acid on September 26. How often does a company ask a government agency to rescind approval of their product?

First OK'd as animal feed additives in the 1940s, arsenic-containing compounds remained legal for use in U.S. chicken, turkey and swine production for the next 70+ years. They were never approved as safe for animal feed in the European Union, Japan and many other more reasonable countries.

If you want to fill up on arsenic from now on, you'll just have to eat rice.

See also: FDA Finds Low Levels of Arsenic in Rice

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