“Modified” hydrofluoric acid (MHF) is a dangerous industrial chemical used in massive quantities in only two California refineries, Torrance and Valero, Wilmington. If released, it forms a ground-hugging cloud that can drift for miles, causing death and injury. The refineries’ other mitigation measures, like water sprays and barriers, are also ineffective. Mass casualties can result from an MHF release — wind direction determines who dies.

Results of 2015 explosion that nearly released 50,000 lbs of MHF, which could have killed or injured tens of thousands, according to the U.S. Chemical Safety Board


For decades, the South Bay has battled the refineries’ all-too-successful campaign to keep using MHF rather than converting to a much safer process, such as is used at Chevron in El Segundo and the other California refineries. Following the massive Torrance refinery explosion in February 2015, which nearly released 50,000 lb of MHF, investigations by TRAA and the U.S. Chemical Safety Board uncovered the true threat MHF poses. Now, the South Coast Air Quality Management District (SCAQMD) is considering Rule 1410 to require MHF/HF replacement with a safer alternative at both refineries. But industry is fighting back with well-financed campaigns.


TRAA has initiated a campaign to urge the State of California to investigate the use of HF in a densely populated area. You can lend your voice to that campaign by posting your thoughts on the state portal. We’ve made it easy! Simply go to our campaign page and use the text that we provide, or type in your own thoughts.


Click image to watch a terrifying video of the Philadelphia Energy Solutions refinery explosion on Friday, June 21, 2019. Note object being hurled from the explosion to the right. With the PES refinery closing, now Torrance CA has the infamous distinction of having the densest population around an HF refinery.  The video is from 6abc/WPVI−TV Action News in Philadelphia.

  • TRAA Kicks-off Campaign Urging Gov. Newsom to Initiate Investigation of HF Usage February 18, 2020
    Last February 15, 2020, the TRAA hosted a press conference and Call to Action at the Doubletree Hotel in Torrance.  In addition to commemorating the 5th anniversary of the explosion at the Torrance Refinery, the group announced an initiative to urge California Governor Newsom to request that Atty Gen. Xavier Becerra’s office open an investigation ...
  • Press Conference on 5th Anniversary of Torrance Refinery Explosion February 15, 2020
    TRAA activists hosted a press conference on Saturday, February 15, 2020 to commemorate the 5th anniversary of the Torrance Refinery explosion. It was a terrific day for TRAA and the campaign to Ban HF. Some of the notables about the morning: Approximately 100 people filled the room Many signed up for areas to help or donated to the ...
  • TRAA 5th Anniversary of Torrance Refinery Explosion Press Conference/Event February 10, 2020
    Join us for a commemoration of the 5th anniversary of the Torrance Refinery explosion.
  • 15 State AG’s Sues Trump Admin EPA for Gutting Chemical Safeguards February 1, 2020
    The coalition is challenging the Trump EPA’s rollback of Obama-era amendments to its “Risk Management Program” (RMP) regulations, referred to as the Chemical Disaster Rule. This rule made critical improvements to the RMP to better safeguard against explosions, fires, poisonous gas releases, and other accidents at facilities that store and use toxic chemicals.
  • Congressman Alan Lowenthal Expresses Support to Proposed Rule 1410 January 29, 2020
    Last November, Congressman Alan Lowenthal joined fellow local congressmembers Ted Lieu, Maxine Waters, and Nanette Barragán in expressing support to the Southern California AQMD Proposed Rule 1410 to replace HF and MHF at the refineries within the SCAQMD jurisdiction. Congressman Lowenthal represents the 47th congressional district, which includes Long Beach, but extends eastward to include parts ...
  • CSB Releases Update to Philadelphia Refinery Explosion January 28, 2020
    The United States Chemical Safety Board has released an update to the ongoing investigation into the June 21, 2019 explosion at the Philadelphia Refinery. In it, the CSB reports that 5,239 pounds of HF were released into the atmosphere, and that only a fraction was contained by the water curtain system designed to contain ...
  • EPA Announces Settlement with Torrance Refinery on Safety and Risk Management Violations January 13, 2020
    The United States Environmental Protection Agency has announced a settlement agreement with the Torrance Refinery regarding violations in handling of Hydrofluoric Acid.
  • Appeals Court Rules that Exxon Mobil Must Produce Documents on 2015 Explosion December 15, 2019
    Statement from Chemical Safety Board’s Interim Executive Authority Dr. Kristen Kulinowski In a unanimous decision, a three-judge panel of the U.S. Ninth Circuit Court of Appeals yesterday ruled that Exxon Mobil Oil Corp. must produce information to the CSB related to a tank filled with hydrofluoric acid at the site of a 2015 oil refinery explosion ...
  • Updates from TRAA December 14, 2019
    Thursday night the TRAA team performed well at the AQMD community meeting on fence line monitoring.  Eight members attended (with short notice) and made excellent presentations and questions to the staff. Together we made the following points. That HF which is an acute problem should be separated from the monitoring of chronic pollutants. – Al Sattler, ...
  • Cause of Philadelphia fire sounds alarm over aging U.S. refineries November 13, 2019
    A new analysis from Reuters shows the dangers at refineries across the country due to aging and unmaintained equipment. The PES fire and explosion “stemmed from equipment installed in the 1970s that had been allowed to run to failure”. Remember, the Torrance Refinery has been using HF Alkylation since about 1959. From Reuters via CNBC (Follow Link for ...