About 250 people marched down Massachusetts Avenue last night in a candlelight procession commemorating the third anniversary of the controversial death of Karen Silkwood, a nuclear plant worker who attempted to expose her company's violations of safety and quality standard rules.

The procession, sponsored by the eastern federation of Supporters of Silkwood (SOS) and Boston chapters of various anti-nuclear power organizations, marched from a rally held at the Young Women's Christian Association (YWCA) building in Cambridge to a memorial service at the Old Cambridge Baptist Church.

Numerous SOS groups held similar marches in 50 other cities, James A. Garrison, a member of the Eastern Federation SOS board of directors said last night.

"The story of Karen Silkwood can not be seen as an isolated case, but rather as an example of a conscious government policy to harass nuclear dissidents," Garrison said.

Karen Silkwood, a worker at the Kerr-McGee plutonium plant in Crescent, Oklahoma, collected documented evidence of her company's violations of health, safety, and quality standard rules.

An unexplained attempt was made on Silkwood's life through the contamination of her house with plutonium after she brought charges against the Kerr-McGee plant to the Atomic Energy Commission.

While traveling to present her compiled documents to a labor union official and a New York Times reporter, Silkwood hit a concrete culvert and was killed. Two federal investigations concluded that Silkwood's death was accidental.

Daniel P. Sheehan, chief counsel for the Silkwood case, said last night that the Silkwood family is suing Kerr-McGee officials for failing to account for all of the company's stored plutonium, for violating health and standard rules, and for violating Silkwood's civil and union liberties.

They are also charging four FBI officials for covering up the facts in their investigation. A federal court in Oklahoma will try the case next April.