Retired slugger Mark McGwire told Congress' investigation of drugs in baseball that he would not "participate in naming names" of players who used steroids.
McGwire, one of six current and former stars appearing Thursday before the House Government Reform Committee, did not say whether he used steroids. He said his lawyers advised him not to answer certain questions.
Two current players, Sammy Sosa and Rafael Palmeiro, said they never had used steroids. All three were accused of using performance-enhancing drugs by Jose Canseco in a best-selling book that helped prompt the daylong hearing.
"If a player answers, 'No,' he simply will not be believed," McGwire said. "If he answers, 'Yes,' he risks public scorn and endless government investigations."
It was an extraordinary sight some of the top names in baseball history wearing business suits on Capitol Hill instead of uniforms on a diamond.
Two top sluggers who were not present testified in 2003 to a San Francisco grand jury investigating a steroid-distribution ring: Barry Bonds of the San Francisco Giants and Jason Giambi of the New York Yankees.
In a tense scene, Canseco sat at the same table as the other players as he told the lawmakers that he could not fully answer their questions because of concerns his testimony could be used against him.
During a break after the players' opening statements, five of the stars gathered in one nearby room, and Canseco went to another.
Choking back tears, his voice cracking, McGwire said he knows that steroid use can be dangerous and will do whatever he can to discourage young athletes from using them.
"What I will not do, however, is participate in naming names and implicating my friends and teammates," said McGwire, who ranks sixth in major league history with 583 homers.