After Weeks of Issues, Valero's Benicia Refinery to Temporarily Shut Down

Updated Sunday, 11:30 a.m.

The Valero refinery is performing a controlled shutdown to "improve conditions and minimize risk," according to a statement from Benicia city officials. The shutdown could last multiple days and result in visible flaring.

Earlier Sunday, city officials issued an advisory notice for residents with respiratory issues to stay inside after a 2-week-old problem at the Valero refinery worsened.

But now that the refinery is shutting down, city officials and Solano County health officer Bela Matyas say the air quality is safe for residents.

Valero Advisory Update - 10:30 a.m.
Benicia Fire Department continues to monitor air quality. Readings show that levels have significantly improved and are currently in the safe range. #ValeroScrubberIncident

— City of Benicia (@CityofBenicia) March 24, 2019

The problem at the Valero refinery began on March 11 when a malfunction involving one of the refinery's units led to the release of petroleum coke dust.

A Valero representative said then that the refinery's flue gas scrubber was "experiencing operational issues."

The releases prompted local air regulators to issue seven notices of violation against the refinery. 

Those problems eased after a few days but continued intermittently, air district officials said.

On Saturday several Benicia residents posted comments on the social media site Nextdoor, expressing concerns about what appeared to be more black smoke coming from Valero's stacks.

On Sunday, the particulate matter in the air increased.

"The concentration of particulate matter has become significantly higher over the past day. The emissions contain coke, a by-product of the refining process that is made up primarily of carbon particles," the city's statement said.

Benicia officials said testing of the coke dust released so far did not show heavy metals at harmful levels but warned that breathing in air from the releases could worsen underlying respiratory conditions like asthma.

“Inspectors are on scene working with the facility and with Solano County and making a determination if additional violations will be coming,” said Lisa Fasano, a spokeswoman with the Bay Area Air Quality Management District.

The air district also deployed a monitoring van to drive throughout Benicia to "gather ground-level emissions data."