"The USADA letter does not allege that Tim Montgomery took any banned substances," the athlete's attorney Howard Jacobs said in a statement.
"However, the conclusion by USADA's review board -- whose members were all chosen by USADA's CEO, Terry Madden, and is hardly an independent body -- to proceed with the adjudication process based on some vague assertion of Tim's alleged involvement with BALCO further underscores the basic lack of fairness in this entire process.
"USADA's leap to judgment on the flimsiest of so-called 'evidence' confirms our worst suspicions -- that it is resorting to McCarthy-like tactics in its efforts to ruin Tim's reputation."
Earlier, the lawyer for Michelle Collins also confirmed that the former world indoor 200 metre champion had received a letter from the USADA charging her with a doping violation.
Under USADA rules, the 100 metre world record holder and Collins have the option of accepting a suspension or appealing either to an American Arbitration Association (AAA) panel or the Swiss-based Court of Arbitration for Sport (CAS).
"I have just received a letter from the USADA that states a review panel has determined there is sufficient evidence to proceed with the adjudication process," attorney Brian H. Getz told Reuters in a telephone interview from his San Francisco office.
"They are making it a formal charge. They are charging her with violating the anti-doping rules.
"The so-called evidence the USADA is relying on is woefully thin and I think before any fair arbitration panel we will win,"
Montgomery and Collins were two of four U.S. sprinters sent letters last week by the USADA alleging doping violations in connection with the BALCO doping scandal.
Letters also went to Olympic 400 metre silver medallist Alvin Harrison and sprinter Chryste Gaines.
Harrison's attorney, Edward Williams of New York, would not comment when asked whether his client had been charged with a doping offence while Gaines representatives could not be reached for comment.
Montgomery's partner triple Olympic champion Marion Jones is also under scrutiny by the USADA but has not been charged with any offence. She and Montgomery have persistently denied taking performance-enhancing drugs.
According to a report in the Los Angeles Times, however, the evidence the USADA holds against Montgomery is compelling.
Leaked documents obtained by the newspaper allege Montgomery used a cocktail of banned drugs, including five steroids plus the blood-booster EPO, human growth hormone and insulin.
The newspaper said the allegations were detailed in a nine-page USADA letter sent to Montgomery on June 7.
The existence of that letter was made public by Montgomery's lawyers the following day but not its precise contents.
The decision to pursue a doping ban against Montgomery is sure to send shockwaves through the sporting world with the Athens Games now less than two months away.
The 29 year-old American would represent the biggest scalp for anti-doping campaigners since Canada's Ben Johnson was stripped of the 100 metre gold medal at the 1988 Seoul Olympics after testing positive for steroids.
Montgomery shot to fame at the Grand Prix final in Paris two years, setting the world record in a blistering 9.78 seconds.
But for much of his career Montgomery had appeared little more than a solid, journeyman sprinter.
He did not qualify for the U.S. team at the 1996 Atlanta Summer Games but the next year took third at the 1997 world championships in Athens.
His performance slipped over the next few years, placing sixth at Seville world championships while failing to qualify in either the 100 or 200 metres for the 2000 Sydney Olympics
Montgomery finally began to emerge as a front line sprinter at the 2001 Edmonton world championships when he ran 9.85 in finishing second to Maurice Greene.