Marion Jones is free to return to the track again, her record and reputation cleared after a backup drug test came up clean.

The “B” sample taken from one of the world’s best-known and most decorated sprinters did not detect the banned endurance enhancer EPO, her attorneys said Wednesday night – a stunning result that resurrects her career almost as quickly as it was nearly dashed earlier this summer.

The finding means her initial positive result is thrown out, clearing her of the most recent – and most damaging – allegations and paving the way for her return to the sport she defined in the late ’90s and early this decade.

“I am absolutely ecstatic,” Jones said in a statement released by her lawyers. “I have always maintained that I have never ever taken performance-enhancing drugs, and I am pleased that a scientific process has now demonstrated that fact.”

Long a target of governing bodies in track and the Olympic movement, Jones tested positive for EPO on June 23, after winning the 100 meters at U.S. nationals for her first sprint title since 2002.

She withdrew from the 200 meters the next day and was slated to race at a meet in Switzerland in August but withdrew unexpectedly. Hours later, reports of her positive “A” test for EPO were revealed.

She faced a minimum two-year ban, pending the result of the backup, or “B,” test, conducted at the same UCLA lab using the same sample. That sample came back negative.

“I am anxious to get back on the track,” Jones said.

The International Association of Athletics Federations is awaiting notification of the lab result.

“We have not received any formal notification from the lab,” IAAF spokesman Nick Davies said Thursday. “Until then, we can’t comment. Only until we receive the notification and accept the explanation can we make any decision on her eligibility.”

EPO is also known as Erythropoietin, a banned performance-enhancer that can boost endurance.

Jones, who has five world championships, dominated track and field in the late 1990s. At the Sydney Games, she became the first woman to win five Olympic medals – taking gold in the 100 meters, 200 meters and 1,600-meter relay and bronze in the long jump and 400-meter relay.

Since then, her reputation has suffered. She is one of several athletes who testified to the federal grand jury investigating BALCO in 2003.

Her ex-husband, C.J. Hunter, and Bay Area Laboratory Co-operative founder Victor Conte have accused her of using banned substances, allegations she has denied.

Her former coach, Trevor Graham, has been linked to several athletes in trouble for doping, including Justin Gatlin, who recently tested positive for testosterone or other steroids and faces a possible eight-year ban.

Last December, the father of Jones’ son, sprinter Tim Montgomery, retired after he was banned for two years for doping violations – the result of information gathered in the BALCO probe.

Earlier this year, the International Olympic Committee said it would continue to investigate Jones’ performance in Sydney to determine whether she was doping then.

Jacobs said the turnaround in Jones’ case places a burden on sports federations and those who administer the tests to make sure they’re doing a good job and following protocol.