Investigators say the substation holds about 30,000 gallons of oil. It's unclear how much of it has already burned off.

Crews have not determined the cause of the fire and are working to restore power to affected customers, officials with Oncor said.

FORT WORTH, Texas (KTVT) - Emergency crews are responding to a fire following an explosion at a power substation in North Fort Worth on Wednesday. The incident off Seventeen Lakes Boulevard and Henrietta Creek Road was reported at about 7:15 p.m.

An explosion at a power substation in North Fort Worth caused a massive fire Wednesday evening, prompting the voluntary evacuation of nearby homes. The incident, located off Seventeen Lakes Boulevard and Henrietta Creek Road,