Gary Wadler, one of the strongest voices in the fight against performance-enhancing drugs in sports, has died. He was 78.

Wadler’s wife told The New York Times that her husband died of multiple system atrophy, a degenerative neurological disorder.

Wadler testified in front of Congress in the 1990s about the way doping was undercutting the Olympics and threatening the health of elite athletes and, potentially, those who tried to emulate them.

He chaired the World Anti-Doping Agency committee that considers which substances should be banned in sports, and was a leading critic of the way American sports leagues, especially the NFL and Major League Baseball, ran their anti-doping programs.

When the NFL agreed to use blood testing for human growth hormone, Wadler was skeptical, wondering if the program itself would have any teeth.

“The devil’s in the details,” he said. “The rest of the story might be equivalent to having no testing at all.”

He sounded similar warnings when baseball started its testing programs in the wake of a steroid scandal that sullied the sport in the 1990s.

In 1989, Wadler co-wrote a book “Drugs and the Athlete” that was a first-of-its-kind in detailing the impact steroids have on athletes and sports. The International Olympic Committee honored him with its President’s Award.

“He was an early pioneer in the effort to protect the health and safety of athletes, and he’ll be missed,” said Travis Tygart, the CEO of the U.S. Anti-Doping Agency.