At least five winning racehorses have been disqualified from races at Lone Star Park in Grand Prairie this year after testing positive for trace amounts of meth, according to Texas Racing Commission officials.

The horses tested positive for methamphetamine during a thoroughbred race meet held April 7 through July 17, commission records show.

During that time, the commission also reported seven human drug violations, and officials believe the horses may have been contaminated by their handlers, known as grooms.

The Texas Racing Commission issued rulings to the owners of the five horses — Cape Caduceus, Majestic Holiday, It's About the Cat, Cheval De Montagne and Gospel Teresa — that retroactively disqualified the horses from the races and ordered the purse to be redistributed to their competitors in the affected races.

Texas Racing Commission officials issued the rulings Aug. 17. They took no further action against the owners of the contaminated horses.

Robert Elrod, public information officer for the Texas Racing Commission, said in addition to the five winning horses, one horse that placed second in a race on April 23 — U.S.A. Destroyer — was also disqualified.

Elrod said there's no way to determine whether the trace amounts of methamphetamine affected the horses during races, but it is possible.

Chuck Trout, the commission's executive director, said the drug "just popped up" at Lone Star Park. Many of the teams that competed in Grand Prairie had also competed at Sam Houston Race Park in Houston from January to March, but no horses tested positive for meth during that meet.

Not all of the rulings detail the amount of the drug found in the racehorses, but two of the rulings say urine samples taken after the races contained levels of the drug around 0.5 nanograms per milliliter. A nanogram is one-billionth of a gram.

"The low level of methamphetamine in the sample, and its absence in serum, as well as other facts presented in the case file indicate that this positive test is a case of human contamination instead of intentional administration," the rulings all read.

It is unclear how the racehorses were contaminated with the drug, but Marsha Rountree, executive director of the Texas Horsemen's Partnership, said during a commission meeting Aug. 9 that the contamination levels were so low that the horses are likely being contaminated by horse grooms using the drug. Grooms made up the majority of people cited by the commission for drug use violations.

"It was very concerning to all of us in the horseman's organization, and most especially the trainers whose horses were coming up positive," Rountree said at the meeting. "We became very proactive."

Gary Aber, a member of the Texas Racing Commission, said during the Aug. 9 meeting that he wanted the organization to pursue a zero-tolerance policy regarding contaminated racehorses or grooms that test positive for the drug.

"That way, if a horse comes up positive, the horse is positive," Aber said. "That horse needs to be shut down."

Elrod said the trainers of the contaminated racehorses could have faced a one-year suspension and a $10,000 fine, but the commission chose not to punish the owners further.

Jim Blodgett, director of investigations at the commission, said employees at racing facilities who test positive for drugs are given a mandatory 30-day suspension. They also have to receive counseling and provide a clean urine sample before they are allowed back by the stewards.

"I think that's way too lenient, and so I would like for us to take a look at that," said Rolando Pablos, chairman of the Texas Racing Commission.

Trout said the commission is working on instituting a random drug test policy for stable employees, but it is unclear when that policy will be instituted.

Rountree said racehorses in several other states have been cross-contaminated with drugs before. It's not just a Texas issue.

"It is happening everywhere, so much so that Oklahoma had to come in and actually establish a threshold for methamphetamine and caffeine because of the cross-contamination," Rountree said.

One other case of contamination has been reported in Texas at Gillespie County Race Track in Fredericksburg. Other instances of contamination have occurred in California, Minnesota, Kentucky and Australia.