"It's serious and it's harming the reputation of the sport," Sen. John McCain, R-Ariz., said Wednesday shortly before the start of hearings before the committee he heads.
He told ABC's "Good Morning America" that the best solution would be for pro sports — particularly baseball — to move aggressively to combat steroid use and that the main purpose of the hearing is to "shine a lot of sunshine on this issue and ... the extent of problem."
But he said if baseball does not deal with the problem, Congress would have to "contemplate further action."
"To be frank, I would be less concerned about what professional athletes are doing to their bodies if their actions did not have such a profound effect on kids," said Sen. Joe Biden, D-Del., in prepared remarks before the Senate Commerce Committee.
Commissioner Bud Selig and Donald Fehr, leader of the players' union, were appearing to give baseball's side of the controversy.
Biden is sponsoring legislation that would ban over-the-counter sales of androstenedione, a steroid-like supplement that Mark McGwire used the year he broke the single-season home run mark, and the newly detected steroid THG.
He and other lawmakers also want to see the sport adopt a more stringent testing program for drugs that already are banned.
"To keep players honest, there needs to be a better system of random drug testing and real consequences for players who test positive," Biden said.
In his prepared remarks, Selig said major league baseball would like to have a stronger plan but couldn't get the Fehr's union to agree.
"Ultimately, the agreement we accepted on drugs was a compromise," he said. The sport, he said, supports Biden's legislation.
"I realize that we have work to do," Selig said. "We need more frequent and year-round testing of players. We need immediate penalties for those caught using illegal substances."
Last year, 5 percent to 7 percent of players tested positive for steroids, in tests they knew were coming. That will trigger two more tests this year, although a player won't face a year's suspension until the fifth offense.
The National Football League, by contrast, has a year-round random testing program for players and imposes immediate suspensions on those who test positive for banned substances.
Baseball players have gotten larger and stronger in the last 10 years as the game's signature power play — the home run — became much more common. Some believe players have taken illegal drugs to boost their performances and cash in on huge contracts available to the game's premier power hitters.
The suspicion that some of the game's greats are using steroids has loomed over spring training this year.
The San Francisco Chronicle, quoting information it said was provided to federal investigators, reported last week that steroids were given to San Francisco Giants star Barry Bonds, who broke McGwire's record in 2001; New York Yankees stars Jason Giambi and Gary Sheffield; three other major leaguers; and one NFL player. Bonds, Giambi and Sheffield have denied using steroids.
That report came out of a grand jury investigation of the Bay Area Laboratory Co-Operative. Last month, two company executives, along with Bonds' trainer and a coach who has worked with some of the world's top track athletes, were charged with supplying steroids to athletes.
There are indications that players themselves are more receptive to a strong testing program. Last month, Atlanta Braves All-Star relief pitcher John Smoltz recommended tougher testing, saying the game's integrity was at stake.
"There's a way they should do tests," he said. "Do them the way they should be done — not a platform that's just a smoke screen."