DEVELOPING: Four people were seriously injured in an explosion at a one-story commercial building in Los Angeles, KTTV reported. There were reports that there may be others trapped in the rubble.
A pair of compressed natural gas cylinders were found inside the building, but inspectors are still trying to determine the cause of the blast, city officials told the station.
Rescue workers are at the scene of the partially-collapsed building at 12349 Gladstone Ave., The Los Angeles Times reported.
It is unclear what sparked the explosion.
