BOSTON (AP) _ Like many workers in the defense industry, Santo Alba saw his duties increase as his employer, Raytheon Co., made major layoffs to lower costs.

The 55-year-old foreman of the sheet metal shop was working 70 to 80 hours a week, by his family's estimate, on May 15 _ the day his supervisor told him his workload would increase again.

That afternoon, Alba apparently stuck his head into a giant circular saw used to cut sheet metal and was decapitated. Co-workers at the missile plant in Bedford made the gory discovery. His death was ruled a suicide.

Alba's family says he was worked to death.

Alba's relatives allege that Raytheon knew he was driven by mental illness to put in long hours and yet did nothing to stop him. Alba had been diagnosed with manic depression in 1994.

On Oct. 2, the family filed a complaint with the Massachusetts Commission Against Discrimination in the first step toward a lawsuit that their lawyer said will demand millions of dollars.

``If you have an employee who is suffering from a mental illness and you do not take that into account in the job functions, then you are not properly accommodating them under the Americans with Disabilities Act,'' said Jeffrey Newman, attorney for Alba's wife, Dolores, and their two sons.

It is the latest in a growing number of legal actions involving depression and other mental illnesses brought under the 5-year-old federal act, which requires employers to make reasonable accommodations for qualified workers with disabilities, including psychological illnesses.

``Employers are allowed to require an employee to perform the essential functions of the job,'' said Wendy Parmet, a Northeastern University law professor who specializes in discrimination cases. ``What the ADA says most clearly to employers is that you have to make a careful, thoughtful individual determination when there is an emotional disability.''

In September, Martin Putnam, a lawyer for Pacific Gas & Electric in San Francisco, won a $1.1 million award against the utility, which had asked him to resign when he became depressed.

Putnam, 46, who made $90,000 a year, claimed the utility should have reduced his hours because of his periodic despair. It was one of the largest awards ever in a discrimination case involving emotional problems.

Newman said such cases will become more common because of the ``sweatshop mentality and the overwork'' he said have resulted from downsizing.

``Companies want to increase their bottom line and they tend to overwork their employees in violation of the law,'' he said.

Alba's duties were reduced after he was hospitalized in 1994 and his illness diagnosed. But as Raytheon began a period of cost-cutting and layoffs, his workload steadily increased until his death, his family says.

Documents show that supervisors considered Alba an obsessive who voluntarily worked long hours and weekends.

Newman said the company should have stopped him.

``A person who labors under a mental illness can't make the determination as to how much work they can do,'' he said. ``It is the responsibility of the employer to recognize that and to protect their safety.''

Raytheon officials declined to talk specifically about Alba's case, saying his medical and employment records were confidential.

Company spokeswoman Elizabeth Allen said Raytheon has a free, confidential support network for anyone who is under stress. She said the company regularly adjusts the schedules of employees whose doctors _ including psychiatrists and psychologists _ recommend it.

``This is really a terrible tragedy and we are doing our best to help people cope as best as they can with this tragedy,'' Allen said. ``We're not prepared to get into a public argument, however.''