George Mitchell is a director of the Boston Red Sox baseball team
Dozens of players have been linked to taking performance-enhancing substances in a report on Major League Baseball that alleges a serious drug culture.
Former Senator George Mitchell, who led the investigation, said several All-Stars were suspected of using steroids and human growth hormones.
He also called for MLB to outsource drug-testing and form an investigative arm to pursue allegations of drug use.
In response, MLB head Bud Selig said he embraced all the recommendations made.
Speaking at a news conference, he said that baseball fans "deserve a game that is played on a level playing field, where all who compete do so fairly".
The players implicated in this scandal read like a who's who of the modern-day game, the BBC's Matthew Price reports from New York.
Baseball is one of America's most popular sports, and he says allegations of widespread drug-use will be deeply disappointing to fans.
Among those named in the report is Barry Bonds, who pleaded not guilty last week to charges of lying to a jury about steroid use.
Prosecutors allege that the San Francisco Giants outfielder, who became the sport's record home-run hitter in September, lied under oath when he said in 2003 that he had never knowingly used performance-enhancing substances.
Mr Bonds has denied accusations that he had used a previously untraceable steroid from a San Francisco-based company called Balco.
The inquiry was instigated by Mr Selig, the MLB Commissioner, in March 2006, following the publication of a book that alleged the use of performance-enhancing substances by Mr Bonds.
Mr Mitchell's report concluded that there was evidence that all 30 Major League clubs were affected by use of banned substances.
"For more than a decade there has been widespread illegal use of anabolic steroids and other performance-enhancing substances by players in Major League Baseball in violation of federal law and baseball policy," Mr Mitchell said at a news conference.
"The response by baseball was slow to develop and was initially ineffective, but it gained momentum after the adoption of a mandatory random drug-testing culture in 2002."
The inquiry began after allegations about Barry Bonds surfaced
Those linked to suspected drugs use in the report include some of the sport's biggest stars: Roger Clemens, Barry Bonds, Jason Giambi, Gary Sheffield, Eric Gagne, Miguel Tejada, David Justice, Chuck Knoblauch and Andy Pettitte.
All the players were invited to respond to the allegations in the report. Whether they will face disciplinary action is unclear, especially as many no longer play in Major League teams.
Roger Clemens has vehemently denied allegations about alleged steroid use, and his lawyer said Clemens was outraged that his name had been included in the report.
Any penalties for active players are unlikely to be as severe as the 50-game suspensions given to those who have recently tested positive for steroids.
Mr Mitchell, a former Senate Majority Leader, urged baseball's authorities to look to the future rather than penalising players for past offences, many of which occurred when different policies were in place.
He also called on the public and media not to focus solely on who was named in the report - and for baseball to be allowed "a fresh start".
But Dick Pound, head of the World Anti-Doping Agency, called for sanctions against offenders.
"These are people who knowingly broke the rules, defrauded the public, defrauded their fellow players. I think there should be consequences for that," he said.
"It's very disappointing to see former Senator Mitchell saying, 'Oh well, boys will be boys'".
Several media reports have said that had it not been for a former New York Mets bat boy, Mr Mitchell's report would have been far less revealing, as the players and their union were uncooperative and his inquiry did not have the power of subpoena.
Kirk Radomski, who pleaded guilty to distributing steroids in April, testified that he provided banned steroids, human growth hormones and stimulants to dozens of players by mail order between 1995 and 2005.
Media reports about doping in baseball began in the late 1980s, but the sport did not start testing and punishing players until more than a decade later.
MLB and its players agreed in September 2002 to test for steroids, but penalties were not introduced for positive tests until 2004.
A ban on human growth hormones was agreed in 2005, although there is no reliable test to detect the substances.
The report also criticised MLB officials and the players' union, and called for major changes in the league's drug-testing programme:
- Appointing an independent administrator or hiring an outside agency to run the sport's drug-testing programme. It is currently run by the MLB in conjunction with the players' union
- Ensuring "state-of-the-art" testing, including introducing additional year-round tests
- Allowing the testing administrator to actively investigate "non-analytical positives" - information which shows a player broke rules in the absence of a positive drug test
- Improving player education about performance-enhancing drugs
Mr Mitchell said one of the most serious consequences was that "hundreds of thousands" of high school-aged athletes had also been encouraged to use banned substances.