UPDATE: 1 SCE Employee Killed, 3 Injured In Maintenance Accident

UPDATED AT 6:30 P.M.: As investigators continue digging into what caused today's deadly accident in Menifee that killed one Southern California Edison employee and injured three, a spokesman for the utility confirmed the incident took place in a small underground electrical vault as workers conducted maintenance for the utility.

Winchester resident Jose Raul Ros, 38, died as a result of an explosion and fire in the vault located at 29541 Murrieta Road in Menifee, according to the Riverside County Coroner's Office. The incident occurred at 7:40 a.m. and Ros was pronounced dead at the scene at 8:03 a.m. 

The coroner reports Ros was the victim of an "electrical explosion and fire."

[CLICK HERE FOR AN UPDATED STORY ABOUT ROS.]

SCE local public affairs manager Raymond Hicks said he could not confirm the cause of today's accident.

"We are still investigating," he said.

The SCE employees were doing maintenance work, Hicks confirmed. Ros and another SCE employee were in the vault during the incident, he said. Two SCE workers outside the vault attempted a rescue, he confirmed.

The three survivors all suffered minor injuries due to smoke inhalation and were transported to local hospitals but have since been released, Hicks said.

A call to the California Division of Occupational Safety and Health/Department of Industrial Relations has not been immediately returned for this story.

Hicks described the underground electrical vault as a small space with a cement top and a manhole in the center.

The vault feeds power to the nearby Eastern Municipal Water District desalination plant, he said. The plant converts salty, nonconsumable groundwater into potable water using a reverse osmosis process. 

Authorities had originally reported one fatality and two injuries in today's incident, but by noon SCE spokesman David Song issued an updated statement confirming the additional injury.

"Three additional SCE employees were ... injured in the accident and have been transported to area hospitals," Song said.

Murrieta Road was closed between Ridgemoor Road and Park City Avenue most of Thursday.

Riverside County Sheriff's Deputy Albert Martinez reported that power lines were down in the area, and Hicks confirmed the desalination plant was without power much of the day.

Martinez said the incident is not related to yesterday's power outage, but Hicks said he could not confirm that.