The family of a Pomona man who died from accidental electrocution while in custody at a Lancaster immigrant detention center has filed a wrongful-death suit against several government agencies, raising new questions about safety as national authorities crack down on immigration violations.

Cesar Gonzalez, 36, of Pomona, who had been held at the Mira Loma Detention Center for 10 months, died in December when he accidentally jackhammered into an underground power line while on a work detail, according to his family's attorney.

Gonzalez was a construction worker with a wife and two sons.

"It's a tragedy and severe injustice," attorney Gregory Moreno said. "This man was not a threat to anyone. He was a hardworking man with a good job and paying for a house, and he ends up in this tragedy."

After Gonzalez jackhammered into the underground high-voltage line, he was electrocuted as flames exploded around him, according to the suit. Two other injured detainees were also named as plaintiffs.

The two other men were struck by flames and debris and heard Gonzalez "screaming in pain as he was consumed by the explosion and flames, and his pleading with them for help," the lawsuit said.

Gonzalez died two days later at Los Angeles County-USC Medical Center, with the appeal of his immigration case still pending, Moreno said.

Immigration authorities say he was initially detained after he was pulled over on a traffic violation and police discovered

he had a 1990 armed robbery conviction, a deportable offense.

The lawsuit's main defendants are Los Angeles County, the Sheriff's Department and Southern California Edison. The Sheriff's Department runs Mira Loma under a contract with the federal Immigration and Customs Enforcement agency.

The suit alleges the county failed to train deputies and custody assistants on construction and excavation safety rules and the detection of utility lines.

Deputies at Mira Loma referred calls about the lawsuit to a county attorney who did not respond to requests for comment.

Edison officials did not return phone calls.

Once a World War II training base for military pilots, and later a state prison and a county jail mostly for drunken drivers, Mira Loma reopened in 1997 as a detention facility for immigrants awaiting deportation.

Gonzalez was among 74 people nationwide who have died since 2004 while in federal immigration custody, an issue that has raised concern among some in Congress.

The national detainee population was more than 311,000 in fiscal year 2007, a 34 percent jump over 2004.

But ICE officials said the number of deaths per 100,000 is lower for ICE detainees than for the population in U.S. prisons and jails and the general public as a whole.

The number of detainee deaths has declined from 29 in 2004 to seven as of July, ICE figures show.

ICE spokeswoman Virginia Kice said the majority of the 74 who died since 2004 involved medical conditions, and a small number were suicides.

"ICE takes its responsibility to provide for the welfare of those in its custody very seriously," she said, "and we are committed to doing everything possible to ensure the safety and security of our detainees."