Aerial view of affected area at the Exxon/Mobil refinery in Torrance following an explosion and fire on Feb. 28, 2015. (Brad Graverson / Staff Photographer)Aerial view of affected area at the Exxon/Mobil refinery in Torrance following an explosion and fire on Feb. 28, 2015. (Brad Graverson / Staff Photographer)

• Feb. 18, 2015: A massive 1.7-magnitude explosion at the ExxonMobil refinery in Torrance literally rocked the city, showering some neighborhoods with industrial debris and crippling the plant’s ability to refine gasoline, sending pump prices soaring.

• April 2, 2015: Torrance officials warn the city is losing up to $700,000 a month in tax revenue because the refinery is largely inoperable.

• Aug. 13, 2015: Cal/OSHA fines ExxonMobil $566,600 for 19 violations indicating “severe lapses” of health and workplace safety protocols with a half-dozen classified as “wilful” because the company failed to fix a piece of equipment for almost a decade despite knowing it could cause a life-threatening explosion. The company is appealing the citations.

• Sept. 6, 2015: A leak of potentially deadly hydrofluoric acid lasts for at least 15 hours, prompting an investigation by state and federal agencies after city officials say the company failed to follow proper emergency notification procedures. The leak’s cause, whether human error or mechanical failure, has yet to be publicly disclosed.

• Sept. 30, 2015: ExxonMobil announces it is selling its Torrance refinery to PBF Energy in a $537.5 million deal.

• Sept. 30, 2015: CBS News reports that an 80,000-pound piece of equipment flew 100 feet through the air by the force of the February explosion and only missed a vessel containing 50,000 pounds of potentially lethal hydrofluoric acid because it hit temporary scaffolding around it erected for upcoming maintenance. The “near miss” could have caused a “catastrophic release’ with the potential to kill or injure tens of thousands of people, federal officials said.

• Dec. 1, 2015: The U.S. Environmental Protection Agency announces it is probing whether ExxonMobil understated the risk associated with a “worst-case release” of potentially lethal hydrofluoric acid from the refinery. The investigation apparently was prompted by the disclosure that Torrance officials quietly signed off on a court order allowing the reduction in an additive that was supposed to make the acid safer because of gasoline production problems associated with its use.

• Jan. 13, 2016: The U.S. Chemical Safety Board announces preliminary findings in its investigation of the February refinery blast that found “multiple safety violations” at the refinery. Two of three safety systems designed to detect HF leaks were rendered inoperable by the explosion. The company disputes the agency’s characterization of the severity of potential consequences from the accident.

• Jan. 28, 2016: The South Coast Air Quality Management District pledges to review alternatives to HF in a six-month study that eventually could lead to a ban of the acid.

• Feb. 17, 2016: The U.S. Chemical Safety Board confirms it has asked the Department of Justice to compel ExxonMobil to respond to half of the subpoenas issued seeking data about the February blast. Separately, officials with would-be refinery purchasers PBF Energy confirm that the amount of additive in HF was reduced about 15 years ago, as critics suspected.

• Original article online at http://www.dailybreeze.com/general-news/20160217/key-dates-in-the-past-year-since-the-2015-explosion-at-exxonmobils-torrance-refinery