In the first drug busts of the Games, a former Olympic weightlifting champion from Bulgaria was stripped of his silver medal and a hammer thrower from Belarus was kicked out.
There have been a series of doping suspensions and withdrawals prior to the Olympics but Wednesday's expulsions were the first drug positives recorded during the Sydney Games themselves.
The International Olympic Committee said Ivan Ivanov tested positive for furosemide, a weight-reducing diuretic, after winning the silver medal in the 56-kilogram (123-pound) weightlifting class.
Ivanov, a gold medalist at the 1992 Barcelona Games and a former four-time world champion, was ordered to give back the medal and expelled from the games.
With Ivanov's disqualification, the placings were revised. The original third-place finisher, Wu Wenxiong of China, moved up to take the silver, while China's Zhang Xiangxiang was elevated from fourth place to the bronze.
The highest number of positives at any one Olympics was 12 at the 1984 Los Angeles Games and the two positives so far at Sydney match the entire total from the 1996 Atlanta Games.
And a former control officer for drug testing for the U.S. Olympic Committee said there is rampant use of illegal performance enhancing drugs by athletes - including Americans - at the Sydney Games.
"The figures I've heard from the CASA report - Center for Addictions and Substance Abuse - up to 80 percent or 90 percent of athletes could be using drugs," Dr. Wade Exum said Wednesday on CBS News' The Early Show. "Another estimate was five out of eight athletes are possibly using drugs - out of a San Diego researcher."
Exum, who recently resigned from the USOC, has filed a lawsuit claiming his former employer is not interested in stopping athletes from using banned drugs.
But his claim that more than half the American athletes he checked had tested positive for banned substances is soundly refuted by USOC officials.
"A laboratory positive is when a laboratory reports a drug that's in the system that is not supposed to be in the system. That's a banned substance - possibly," Dr. David Joyner, vice-chairman of the USOC Anti-Doping Committee, said Wednesday. "Lab positive is not a doping violation until it's investigated."
The other banned Sydney athlete was Vadim Devyatovsky, a hammer thrower from Belarus, who tested positive for components of the banned steroid nandrolone in an out-of-competition control Sept. 12 in the athletes' village. His sample was 20 times above the permitted threshold, the IOC said.
Diuretics are used to flush fluid from an athlete's body to reduce weight, but also can be used to mask the presence of other performance-enhancing drugs. Nandrolone builds muscle and helps athletes recover faster in training.
Ivanov and Devyatovsky were thfirst athletes banned by the IOC as a result of tests conducted during the games. Eleven others had been banned by their federations as a result of pre-games tests.
Wednesday's expulsions were ordered on the basis of positive results of the "A" samples. In the past, no sanctions were taken until after the backup "B" sample was tested.
Devyatovksi had his "B" sample tested and it also turned up positive, the IOC said. Ivanov's "B" sample also was being analyzed.
IOC director general Francois Carrard said Ivanov had already left the Olympic village. Devyatosvsky had been scheduled to start competing Saturday.
Ivanov, 29, was the Olympic champion at 114-1/2 pounds in 1992 in Barcelona. He won gold at the world championships in 1989, '90, '91 and '93.
IOC medical director Patrick Schamasch said Ivanov is suspected of using the diuretic for making the weight, rather than masking drugs.
The vice president of the International Weightlifting Federation, Sam Coffa, called Ivanov "an idiot" for using the banned substance and said he had disgraced his sport.
"He must have been smelling salts or got too much chalk in his brain," Coffa said.
It's not the first time Bulgarian weightlifters have had Olympic medals taken away for drug use. Mitko Grubler and Angel Guenchev were stripped of gold medals at the 1988 Seoul Olympics the same games where Canadian sprinter Ben Johnson lost his gold in the 100 meters.
Weightlifting has been plagued by drug scandals before and during the Sydney Olympics, with lifters from Taiwan, Czechoslovakia, Romania and Norway suspended over pre-games, out-of-competition tests.
The international federation kicked out the seven-member Romanian team Sunday because three lifters - including two on the Olympic team - had failed drug tests this year.
But the federation lifted the ban on the five "clean" lifters the next day after the Romanian Olympic Committee agreed to pay a $50,000 fine.
Devyatovsky, 23, finished second in the hammer at the junior world championships in 1996. This season, he has improved his performance from 251 feet-10-1/2 inches to 266-11.
The IOC said Devyatovsky tested positive for Norandrosterone and Norethiocholanolone precursors of nandrolone.
The IOC said, as of Wednesday, it has conducted 506 in-competition tests, more than 300 out-of-competition urine tests and 199 combined urine-blood controls for the endurance-booster EPO.
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