A fire broke out around 12:30 p.m. Tuesday in a Schellville pallet factory, which ignited a 1,000 gallon propane tank that exploded in a fireball, sending black smoke into a clear Sonoma sky.

Three local fire stations responded to the fire, and called in Cal Fire helicopter support. Tuesday afternoon at the Sonoma Pacific Company wooden pallet factory in Schellville, near the Schell-Vista fire station.

"The fire was reported in the pallets at the back of the yard," said Steve Akre of Sonoma Valley Fire and Rescue. "As you can imagine the arrangement of fuel with the pallets lends itself to very rapid fire spread and a lot of heat.

Akre added "the propane tank blew as a result of the heat and the fire impinging on that tank."

About 500 away, a battered metal tank was lying across the eastbound lane of Highway 121, having been blown there by the explosion. The CHP closed roads in the area including Fremont Drive at Broadway and Fremont at Eighth Street East.

The three‑alarm fire on Fremont Street burned at the same pallet business that burned in a massive fire in 2007 and again in 2013.

The Sonoma County Sheriff’s Office ordered the mandatory evacuation of all residents within a half mile of the fire at 1180 Fremont Dr. The evacuation was lifted at 2:50 p.m.

Watch a dramatic video (courtesy of Dave Cannon) of the early moments of the fire below:

“It’s ripping pretty good,” said Sonoma Valley Fire Chief Steve Akre around 12:45 p.m., as he headed for the blaze. But an hour later, at the fire scene, he said, "I can say that we’re getting a good handle on the fire."

Fire officials said mid-Tuesday afternoon that the blaze was 80 percent contained.

No injuries were reported from the explosion or the fire, Cal Fire Capt. Will Powers said.

Fire trucks from Schell-Vista, Sonoma Valley, Novato, Glen Ellen and Cal Fire were still on the scene, as is a Cal Fire helicopter.

Electricity is out in some areas in Carneros and Schellville.

Fremont Drive is closed between Broadway and Eighth Street East. Broadway south of Watmaugh is also being closed.

The polling place located at the Schell-Vista Fire Station has been relocated to the Seventh Day Adventist Church, 20575 Broadway due to the fire and road closures near Fremont Drive.

More updates to follow.