Former ironworkers union president Jake West, aged, ailing and facing two trials that included more than 50 felony counts, pleaded guilty to an embezzlement charge in U.S. District Court in Washington yesterday as his first trial was about to get underway.

West, 75, who has a pre-leukemia condition, pleaded guilty to one count of embezzling money from an employee pension benefit plan before Chief U.S. District Judge Thomas F. Hogan. In exchange for the plea, federal prosecutors will drop all the remaining charges against him when he is sentenced.

According to federal sentencing guidelines, West faces the possibility of at least four years in prison.

The surprise plea came on what was to be the opening day of a trial in which West and Leroy E. Worley, the former general secretary of the 135,000-member union, were facing a four-count indictment. The charges include allegations that West gave Worley more than $200,000 in union money so that Worley would retire and not challenge West as union president, and that he inflated Worley's retirement package by $37,000.

Worley's trial will go forward Monday.

West's attorney, Jack R. Ormes, based in California, did not return calls to his cell phone or office yesterday. The plea deal apparently means that West's other trial, now postponed indefinitely, will be canceled and the charges will be dropped.

"That's my understanding," said Michele A. Roberts, West's attorney for those charges.

West is at least the fifth former union official to plead guilty to a series of theft, embezzlement or conspiracy charges that revealed high-level corruption throughout the powerful labor organization during the past 15 years. The union, formally known as the International Association of Bridge, Structural, Ornamental and Reinforcing Iron Workers, is based in the District.

The investigation was a spinoff of another probe involving allegations of corruption within the D.C. police department that was launched in 1997. The police chief at the time, Larry D. Soulsby, was West's friend, frequent dining partner and golfing companion, and authorities were investigating to determine whether Soulsby ever gave the union leader illegal favors. Soulsby denied any wrongdoing and resigned as chief, saying he wanted to spare the police department controversy. He has not been charged with any crime.

But FBI and Labor Department investigators, alerted to the union's financial records in the police case, were drawn to West's expense account reports. West allegedly spent $10,000 in union money on golf outings in Potomac and Palm Springs, Calif., and $7,000 at the Prime Rib, a restaurant in downtown Washington, and stocked his home with expensive liquor.

West reimbursed the union for $1,460 in 1998, saying he had been unaware that his children had spent the money.

"I do not want the International to pay for any items which are of a personal matter or any expenses which are incurred by my family, nor do I want to be put in jeopardy by things which occur that I know nothing about," he wrote.

West stepped down as the $200,000-a-year union president in February 2001. He now lives in Palm Springs.

Hogan had ruled earlier this year that West's illness made him medically unable to be tried on the more extensive charges related to company expense reports -- a trial that was expected to last more more than a month.

But, Hogan ruled, West was fit enough to face trial on the other set of charges with Worley, a case that was was expected to last two weeks, thus setting the stage for yesterday's plea bargain. West remains free pending sentencing.