Long Beach fire and Signal Hill Petroleum crews quickly extinguished an electrical fire that sparked near an oil tank farm in Signal Hill Wednesday morning, officials said. The fire caused a small explosion that alarmed residents near East 21th Street and Redondo Avenue.

Derek Schulz told the Post he heard the explosion around 7:45 in the morning.

“It was a loud explosion,” he said. “[The explosion] rattled the windows—woke up to it.”

Long Beach Fire Department spokesman Brian Fisk said the blast happened when a test station became pressurized, which spewed oil onto a nearby electrical panel, sparking an electrical fire. Long Beach fire crews doused the flames within 30 minutes, Fisk said.

“There was no environmental hazard,” he said.

Crews shut down northbound traffic on Redondo Avenue as they worked to contain the flames, but it was quickly reopened, Fisk said.

Signal Hill Petroleum spokeswoman Alex Rothwell said Signal Hill Petroleum employees responded to the flame and used extinguishers to douse the fire as Long Beach fire arrived. The test station where the fire broke out has equipment for testing the daily production rates of oil wells operated in this area, Rothwell said. No chemicals are stored at this site.

“SHP takes every measure possible to ensure a safe environment for both residents and businesses within the community,” Rothwell told the Post.

Just last week, another explosion blew out the windows of a Signal Hill home after an apparent gas leak. Two residents were taken to the hospital with minor injuries.

There were no injuries reported in Wednesday’s fire.