Newly introduced, identical bills in the U.S. House and Senate would ban the routine use of eight classes of antibiotics in livestock animals. Keep Antibiotics Working (KAW), a slick PR coalition of anti-food-choice activist groups, was especially pleased with the news because their pet statistic became a central “finding” of the bill. Namely: “An estimated 70 percent of the antibiotics and other antimicrobial drugs used in the United States are fed to farm animals.”

This “estimate” can only come from a study by the KAW-member Union of Concerned Scientists, an activist group with a long history of unscientific pronouncements. These include a 1998 report arguing that North Korea could not develop nuclear weapons, and a baseless campaign suggesting that genetically modified corn threatened Monarch butterflies.

UCS admits that its estimate is created from mere guesswork. The organization’s website says that “the data to answer [the following] questions are not available”:

What is the total amount of antibiotics used each year in the United States?
How much of this is used to treat human disease?
How much is used in animal agriculture?
How much is used to treat sick animals and how much to promote their growth?
How much of each major class of antibiotics is used as supplements to animal feed or water?
Is agricultural use increasing? By how much?
Which agricultural uses are most likely to contribute to problems in treating human disease?

Translation: they don’t know what they’re talking about, but they’ve managed to convince members of Congress otherwise.

In addition to the website, the executive summary of UCS’s own report on antibiotics complains about a “gaping chasm” in the data, and the report’s author admitted to Consumer Reports: “We know nothing. We are flying blind.” It is understandable, if unfortunate, that members of Congress presumed a group of self-proclaimed “scientists” would have some real evidence to back up its conclusions.

While the health benefits of antibiotic use (for animals and humans) are clear, the case against their use remains dubious. The microbiologists, risk assessors, veterinarians, and animal health experts at the 42nd Interscience Conference on Antimicrobial Agents and Chemotherapy determined that human-health hazards from livestock antibiotics are “theoretical” at best, and that the actual risk is “very small.” Speaking for the conferees, Dr. Ian Phillips said: “In 50 years of antibiotic use in animals and man, the development of resistance in animals has not made a major impact on human and animal health, and such a development seems unlikely to happen now.”