Independent lab confirms Mayfield drug use

Jeremy Mayfield

NASCAR filed court documents Monday night that show an independent laboratory found an illegal substance in the urine sample that led to Jeremy Mayfield's suspension for a failed drug test.

The documents, part of NASCAR's response to Mayfield's lawsuit to have his indefinite suspension lifted, show that Medtox Laboratories in Minnesota tested both his "A" and backup "B" samples last week and "confirmed the presence" of a substance that is blacked out in the filing.

Both sides are due in U.S. District Court on Wednesday, and Mayfield is hoping a judge reinstates him in time to travel to this weekend's race at Daytona International Speedway.

NASCAR, which is countersuing, argued in its filing Monday that the "safety risk is simply too significant to let Mayfield back on the track."

"No one but Mayfield knows whether his (drug name redacted) use was an isolated event," NASCAR said in its brief.