A hormone used to raise beef cattle may be staying in the environment longer than previously believed and changing the sex of fish, among other effects.

A team of American researchers says the information regulators are using to govern the use of the chemicals in livestock farming is faulty, and the way in which all chemical substances are regulated needs an update. The team published its results in the journal Nature Communications last week.

"It is an example where we don't know as much as we thought, and that means there are consequences we didn't expect," said lead author Adam Ward of Indiana University.

Chase Adams, a spokesman for the National Cattleman's Beef Association, said he was unable to immediately locate anyone able to respond to the findings.

Trenbolone acetate (TBA) is a potent hormone—many times stronger than testosterone. It is an "androgen"—a steroidal hormone that's sometimes used as a performance-enhancing drug by athletes. Though human use of trenbolone is illegal, discussions about it can be found on places such as online bodybuilding forums. It can also be found in the bodies of cows across America.

Read MoreEating crickets: 'Micro livestock' business is booming



Livestock farmers are permitted to use such hormones in the United States, and the use of several of the chemicals is "ubiquitous" among beef producers, according to the researchers. The study cites data saying hormones can reduce costs by about 7 percent, which translates to roughly $1 billion saved annually by the industry in the United States.



The chemicals are illegal to use in farming in some parts of the world, including in Europe.



Trenbolone acetate is regulated, but the rules around TBA are based on the assumption that the chemical breaks down when exposed to sunlight.

But a research team including scientists David Cwiertny and Edward Kolodziej conducted a study in 2013 that found that sunlight appears only to render the substance inert—the chemical can become active again when it's dark out.