A rule challenge filed by two Florida greyhound trainers disputes the validity of drug testing laws for race dogs.

The state suspended the licenses of trainers Charles McLellan and Natasha Nemeth earlier this year after drug tests for dogs they cared for came back positive for metabolites of cocaine.

Florida' Department of Business and Professional Regulation's testing lab found cocaine traces in 18 urine tests of dogs trained by Mclellan, according to state filings in June. The lab also found cocaine in six tests of dogs associated with Nemeth.

RELATED: Five more greyhounds test positive for cocaine at Bestbet Orange Park

The pair had separate appeals pending before an administrative law judge over the summer, but in a joint effort to save their licenses, McLellan and Nemeth have filed a rule challenge together against DBPR.

In the petition filed in September, the trainers' question the procedures the lab follows to routinely test the urine of race dogs.

The trainers' also challenge DBPR's "failure to address environmental contamination" that could happen to the the urine samples.

Kennel and track owners have argued the traces of cocaine found by the lab could have been transferred to the dog from a person's hand and not from intentional doping to fix races.

"There is a significant chance that [DBPR] or the laboratory's chain of custody is responsible for the positive test results," the petition reads. "In one study, a human was found to have passed urine containing 72 ng/ml of BZE (cocaine metabolite) after handling dollar bills."

The hearing on the rule challenge is scheduled for November 15 at Jacksonville's City Hall.

Until a judge makes a decision the validity of the Florida rules, McLellan and Nemeth's suspension hearings will remain on hold.