The suit against Southern California Edison, principal owner of the San Onofre Nuclear Generating Station, comes a year after the U.S. Nuclear Regulatory Commission rebuked the company for what the government called a "chilling effect" on the airing of safety concerns by employees.
In a March 2010 letter cited in the lawsuit and provided to reporters by lawyers for the plaintiff, Paul Diaz, 35, the NRC ordered Edison to address a workplace climate in which workers feared retribution for reporting safety issues.
According to the lawsuit, the NRC inquiry and letter were prompted by anonymous calls and e-mails from plant "insiders" raising concerns about "shortcuts on testing new generators, unreported safety violations, falsifying records and promoting a culture of cover-up."
The lawsuit also cited problems with chronic fatigue among workers caused by lengthy shifts and heavy overtime demands.
Edison spokesman Gil Alexander said in a written statement that the company had not yet been served with a copy of the lawsuit and does not comment on pending litigation.
"However, we can say that, by policy, SCE considers retaliation against employees who raise safety concerns a termination offense," the statement said.
Diaz filed suit in Los Angeles County Superior Court, seeking unspecified damages. The complaint names Southern California Edison and his former supervisor.
The San Onofre plant sits on the Pacific coast near the border of San Diego and Orange counties, about 60 miles southeast of Los Angeles. The two reactors there went into commercial operation in the 1980s.
The state's only other nuclear power plant in operation is the Diablo Canyon facility, owned by Pacific Gas and Electric Company, near San Luis Obispo on the central California coast.
Diaz was first hired at San Onofre in 1999 as a security officer and later promoted into management, his lawsuit says. He left San Onofre in 2008 to work for a northern California company, then was recruited back to the plant in 2010.
His return preceded the NRC letter by a few months, his attorney, Maria Severin, told Reuters.
"Some employees came to him with issues they were afraid to bring up because they feared retaliation," Severin said. "So he brought them up. They his supervisors told him: don't be a superhero."
Diaz, then manager of business and accounting and project service, was fired in October 2010, his complaint states. The ostensible reason for his dismissal was poor performance, but the lawsuit does not give specifics.