A small leak of an oil mixture containing traces of toxic hydrofluoric acid triggered an automated alarm system at the Torrance refinery, Torrance Fire Department officials said Wednesday.
The leak was discovered in the nipple of a valve in the west alkylation unit about 4:50 p.m. Tuesday, said Assistant Fire Chief Steve Treskes.
“It set off a laser sensor, which is what it’s supposed to do,” he said.
A fire engine was dispatched to the refinery as a precaution and the department is conducting a follow-up investigation, Treskes said.
Monitors recorded HF with a density of 1.4 parts per million; refineries are supposed to inform regulatory agencies if a leak exceeds 2 ppm, he said.
The incident comes as the Refinery Committee of the South Coast Air Quality Management District is set to continue an investigatory hearing at 10 a.m. Saturday at City Hall into a series of fires, flares and other incidents at the plant since a February 2015 explosion shut it down for about a year.
An agency review found that pipe leaks or equipment integrity accounted for 17.5 percent of all emergency incidents at the plant since September 2015, more than any other cause.
The plant, owned by PBF Energy, is entering a three-month maintenance period dubbed “turnaround” over the next three months that could produce intermittent flaring, the AQMD notified residents Wednesday.