Update 9:32 p.m.- Oncor said the transformer underground malfunctioned. Everything is fixed and no power is out.

DALLAS (CBSDFW.COM) – The Dallas Fire-Rescue responded to an explosion near 315 South Cesar Chavez Boulevard.

The explosion sent black smoke into the immediate area in Downtown Dallas.

Firefighters said an unknown malfunction in an underground electrical vault caused the explosion and sent a column of black smoke into the air.

Oncor personnel are standing by until the smoke clears.

Nearby buildings have been checked for smoke.

No injuries have been reported.