COLORADO SPRINGS, Colo. — A deal for the U.S. Anti-Doping Agency to police drugs in horse racing cratered Thursday after months of negotiations that the agency’s CEO said did not give it “a reasonable chance to put in place a credible and effective program.”

The USADA was set to become the regulator for anti-doping and medication control for thoroughbred racing under the Horseracing Integrity and Safety Act, which is set to take effect next July.

But in a surprising announcement, CEO Travis Tygart said the deal stalled.

“While we desperately tried to reach an agreement to implement the program, without compromising our values, we have always said the passing of the legislation and the finalization of uniform, robust rules are huge victories for the horses and the equine industry,” Tygart said.

He did not offer specifics about the disagreements that scuttled the deal.

The lack of uniform rules across the nation was underscored when Medina Spirit tested positive for a banned substance following the Kentucky Derby. One key issue was the length of time it would take to corroborate the test with a “B” sample, which was needed to confirm the positive.

The USADA said part of its program would have ensured a faster turnaround on the B sample.

Medina Spirit ended up racing, and finishing third, in the Preakness, the second leg of the Triple Crown, even though his victory in Kentucky was in dispute.

Earlier this month, Medina Spirit collapsed and died after a workout at Santa Anita in California.