A minor oil spill in San Pablo Bay at the Phillips 66 oil refinery this week was most likely caused by a corroded pipeline, a revelation prompting a new set of concerns as the energy company pushes to expand the number of oil tankers that unload crude at the Rodeo facility's marine terminal.
The Monday morning spill, which is the subject of three investigations, released an estimated 25 to 50 gallons of gas oil from a "pinhole leak" on an inactive pipe along the refinery's causeway, according to an email the company sent Contra Costa County health officials and obtained by KQED.
"The cause of the leak is still under investigation, but is believed to have been due to localized corrosion," wrote Morgan Walker, the refinery's health and safety manager.
That disclosure reignited outrage from environmental groups opposed to Phillips' proposal to raise the daily average of oil unloaded at the marine terminal from about 51,000 barrels to 130,000.
The company's request to expand came months after a spill in September 2016 at the same facility that was believed to have been the source of noxious fumes that sickened dozens of people in Vallejo.