A mother and her three young children were severely burned Thursday afternoon when an underground electrical vault exploded beneath them as they walked out of a Pomona shopping mall.
Taken to Pomona Valley Community Hospital and then transferred by helicopter to the Sherman Oaks Community Hospital Burn Center were Jo Lynn Williams, 25, of Pomona; Aaron Williams, 8; Shauna Williams, 7, and 18-month-old Lindsey Martinek.
Steve Gookin, assistant director of nursing at the Pomona hospital, said the mother, Aaron and Lindsey were in serious- to-critical condition while Shauna was in serious condition.
One of the victims reportedly had third-degree burns over 90% of the body while the other three suffered third-degree burns over 60% of their bodies.
No other injuries were reported.
Witnesses said Williams and her children had just walked out of Robert's department store in Indian Hill Village shortly before 4 p.m. when the explosion occurred beneath an outside sidewalk. Shauna Williams, who was directly on top of the blast, was blown about 25 feet with a manhole cover. The heavy steel cover at least protected her somewhat, Pomona fire officials said.
Her mother and the other two children were hurled against the side of the store. The force of the explosion dislodged a 1,000-pound concrete cover just below the steel manhole lid and sent it sliding several feet across the sidewalk.
Lights in the stores went out and authorities quickly evacuated the mall while Southern California Edison Co. crews assessed the problem. Edison spokeswoman Becky Sordolet said later that one of several 12,000-volt switches in the vault apparently malfunctioned, sparking oil that surrounds the equipment.
Power was restored by early evening, but Pomona Fire Marshal Lynn LaRochelle said the mall was still closed while authorities investigated the cause of the blast.