CHARLOTTE, N.C. (AP) — Jeremy Mayfield denied Thursday ever taking methamphetamines, doesn’t know how he failed a random drug test and said his indefinite suspension from NASCAR has ruined his driving career.

Mayfield’s denial comes in an affidavit that was among several hundred pages of documents filed by his attorneys in U.S. District Court. He’s been suspended since May 9 for failing a random drug test conducted eight days earlier at Richmond International Raceway.

“I have never taken methamphetamines in my life, and when accused of taking them I immediately volunteered to give another sample,” Mayfield said in the affidavit, which also says his offer of a second sample was denied.

NASCAR had refused to reveal what drug Mayfield was caught using, classifying it only as a “a dangerous, illegal, banned substance.”

Mayfield sued in late May to have his indefinite suspension lifted, and both sides were barred from discussing his test results. NASCAR is countersuing and alleges Mayfield breached his contract and defrauded NASCAR and its competitors of earnings. Both sides will be back in court July 1.

In the court papers, Mayfield said his 17-year career has been irreparably harmed.

He said the suspension caused his sponsor to stop funding the No. 41 Mayfield Motorsports entry, and he has been unable to find a company willing to work with his team. Mayfield said he’s been forced to lay off 10 employees, and he and his wife have borrowed money from family and sold personal assets to meet their living expenses.

“I do not understand how or why this is happening to me or my family,” he said in the affidavit.