A couple of 8,000-gallon tanks holding diesel fuel exploded Tuesday afternoon at the NuStar refinery in Crockett, shaking the areas of Rodeo, Hercules, and Pinole and sending thick, toxic black smoke into the air.

Dual explosions occurred around 2 p.m., as KPIX reports, and in aerial footage two of the tanks appear to have "collapsed." A tanker driver at the site tells the station she had just arrived and filled out some paperwork when she heard a loud "rumbling" and saw "a bunch of people running." She then drove her truck off the property and "I got to the top of the Cummings Skyway and I could see the tops of two tanks completely engulfed in flames."

The trucker, named Michelle, explains that the tanks don't contain oil or gasoline, but renewable diesel.

Update: As the Chronicle reports, I-80 is closed in both directions, from the Willow Avenue exit in Rodeo up to the Carquinez Bridge. A grass fire is burning in the vicinity as well, and crews are trying to keep the rest of the refinery's tanks cool to prevent any further explosions. The two tanks on fire are expected to continue burning for hours.

Video from a YouTuber below shows the fire ongoing just after 2 p.m. The fire was burning, as KPIX explains, just "a few hundred feet from Interstate 80 just south of the Cummings Skyway in Crockett."

The Contra Costa County Sheriff's Office issued a shelter-in-place order for the area, telling all residents to "Go inside, and close all windows and doors. Turn off all heaters, air conditioners, and fans... [and] Cover any cracks around doors or windows with tape or damp towels."

The incident is reminiscent of the August 2012 fire at the larger Chevron refinery in nearby Richmond.

The plume of smoke is visible from all over the Bay.

Between this and last night's earthquake and today's Hollister earthquake, this is not shaping up to be the quietest of weeks.