The Vietnam War veteran led a successful campaign to halt the military's plans, and has since helped build a nationwide coalition to demand safety and openness in the storage and disposal of chemical weapons.

Williams keeps an eye on operations at Deseret Chemical Depot, 45 miles southwest of Salt Lake City, which set out in 1996 to incinerate the nation's largest stockpile of chemical weapons.

The depot's next and final job is to destroy 6,100 tons of mustard gas.

Williams, 58, is one of six winners of this year's Goldman Environmental Prize, the most prestigious award for environmentalists.

The winners, selected from six regions of the world, are set to receive the $125,000 prize at a ceremony Monday at the San Francisco Opera House.

''We're trying to protect these communities from our own weapons of mass destruction,'' said Williams, a cabinetmaker who now heads the Chemical Weapons Working Group. ''We didn't have to go to Iraq to find these things. They're right here.''

Established in 1990 by the San Francisco-based Goldman Foundation, the annual prize has been awarded to 113 environmental activists from 67 countries. The winners are nominated confidentially by environmental organizations and individuals worldwide.