Questions have arisen over human safety, after a paper published in United States has claimed that horses administered with phenylbutazone have also been slaughtered for human consumption.

Drs Nicholas Dodman, Ann Marini and Nicolas Blondeau, pursued 18 thoroughbreds, which, according to their records, had been administered with phenylbutazone, which is more commonly known as bute. Subsequently, those horses were sent for slaughter.

The study was restricted to racehorses only, as drug records of only those horses are maintained. The authors noted that roughly 67 million pounds of American horsemeat was sent overseas for human consumption in 2009.

“The permissive allowance of such horsemeat used for human consumption poses a serious public health risk”, the authors stated, adding that in United States, horses aren’t raised as “food animals”, which means that measures to make sure that horses administered with barred substances are quarantined from entering the food chain of humans are “inadequate, at best”.

Phenylbutazone is one of the most widely used drugs in treating musculoskeletal injuries in horses.

Titled “Association of Phenylbutazone Usage with Horses Bought for Slaughter: A Public Health Risk”, the paper was published in the journal Food and Chemical Toxicology.