Tammy Thomas, a national-team track rider and resident at the Olympic Training Center in Colorado Springs, could be barred from bicycle racing for life after allegedly testing positive for the anabolic steroid Norbolethone, according to press reports.

The 32-year-old track racer released a statement regarding the lifetime ban, proposed by the U.S. Anti-Doping Agency. She has asked for a hearing; meanwhile, the agency has declined comment, and the U.S. Olympic Committee has yet to make a formal announcement regarding the test.

This is not the first doping controversy surrounding Thomas, who scored a silver medal in the individual sprint behind Russian Svetlana Grankovskaia at the 2001 track world championships, and more recently won the 500-meter time trial at the June 21-23 World Cup in Cali, Colombia. She challenged speedskater Chris Witty’s selection to the 2000 Olympic cycling team only to be declared ineligible after exhibiting elevated testosterone levels. Thomas says it was never proven that the testosterone came from an external source; nevertheless, she drew a year’s suspension.

As for this latest charge, Thomas told the Colorado Springs Gazette she believes a contraceptive may have caused the positive test, which occurred during an out-of-competition check at a March training camp in California.