Daly City police and the California Division of Occupational Safety and Health on Monday are investigating the death of a 19-year-old gas station employee Sunday afternoon.

The employee, San Francisco resident Moustafa Algazawy, was changing a light bulb above some storage lockers at the 76 station at 101 S. Mayfair Ave. when he fell from atop a metal cage that stores propane tanks, Daly City police Sgt. David Mackriss said.

Algazawy was taken to Seton Medical Center where he was pronounced dead.

Firefighters initially said Algazawy had been electrocuted, but Mackriss said an autopsy will determine whether he died from electrocution or from the fall.

A manager who saw Algazawy fall suffered a heart attack, apparently from the trauma of witnessing the incident, Cal/OSHA spokeswoman Krisann Chasarik said. He was transported to Peninsula Medical Center with what Mackriss called a "a severe grief reaction."

Mackriss said the gas station will remain closed Monday while detectives and Cal/OSHA investigate the teen's death.