SAN FRANCISCO (BNO NEWS) — A massive natural gas explosion rocked a neighborhood in the city of San Bruno in central California on early Thursday evening, injuring at least seven people, officials said.

A large fireball was seen by numerous witnesses around 6 p.m. PDT, setting at least 20 homes on fire. Officials said the blaze was caused by a natural gas explosion, not a passenger plane crash as initially feared as the scene is close to San Francisco International Airport.

First responders via emergency scanners initially said a ‘large commercial aircraft’ had crashed in the area, setting scores of homes on fire. But they later said the cause appeared to be a natural gas explosion and not a plane crash.

Both San Francisco International Airport as well as Federal Aviation Administration (FAA) spokesman Ian Gregor confirmed no plane had gone down in the neighborhood.

Scores of emergency responders were on the scene of the disaster to battle the huge blaze, but few details were immediately available on casualties. A spokeswoman for Peninsula Medical Center in Burlingame, several miles from the scene, told BNO News that five people with minor injuries arrived at the hospital by themselves.

A spokeswoman for San Francisco General Hospital in San Francisco said one person was in a critical condition at the hospital, and said another victim was en-route to the facility.

The blast was so strong that residents miles away were able to hear the explosion. “We’re fine. We heard the blast, and we can see the fire,” a witness, who lives about two miles from the scene, told BNO News. “We’re told it’s a gas pump explosion by fire fighters going by.”

Acting California Governor Abel Maldonado commended the ‘swift and courageous response’ of emergency responders. “I commend the swift and courageous response of California’s brave emergency personnel and stand ready to expedite any recovery resources that are needed,” he said.

“I will be closely monitoring the situation with the California Emergency Management Agency and will ensure a swift investigation begins to determine the causes.”

Maldonado takes over as Acting Governor when Governor Arnold Schwarzenegger is out of the state. Schwarzenegger was flying over Alaska when the explosion happened, and did not appear to have been informed about the incident.

“Over Anchorage, AK,” Schwarzenegger wrote on his Twitter account along with a picture of him in his plane. “Looking everywhere but can’t see Russia from here. Will keep you updated as search continues,” he joked.

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