A town hall meeting this week in Superior, Wis., could shed light on an ongoing federal investigation of the Husky Energy refinery explosion and fire last spring that injured 13 and caused the panicked evacuation of thousands of people.

The evacuation was the first time that many local residents learned of a toxic chemical used at the refinery — hydrogen fluoride — that according to a worst-case scenario written by the Environmental Protection Agency could threaten the lives of 180,000 people in the Twin Ports area if accidentally released.

Almost as soon as the fire was put out, and after emergency officials said no hydrogen fluoride was released, alarmed residents began asking questions about the company’s use of the chemical.

The town hall-style meeting, scheduled for 10 a.m. Wednesday at the University of Wisconsin-Superior’s Yellowjacket Union, will include an update from the U.S. Chemical Safety and Hazardous Investigation Board on its investigation. A preliminary report from the agency released in August said the blast could have been caused by a worn valve that allowed air to leak and mix with combustible hydrocarbons. The agency’s final report isn’t expected for several months.

The meeting was requested by U.S. Reps. Betty McCollum and Rick Nolan along with U.S. Sens. Amy Klobuchar, Tina Smith and Tammy Baldwin of Wisconsin.

Numerous people have called for a ban on hydrogen fluoride at the refinery, including the mayors of Duluth and Superior. An advocacy group formed in the days after the explosion, the Twin Ports Action Alliance, also wants a ban on hydrogen fluoride. The group’s co-founder, Ginger Juel, said she hopes to ask the Chemical Safety Board for more information on emergency preparedness and on how hydrogen fluoride is transported.

The company so far hasn’t said if it will use hydrogen fluoride or some other chemical when it rebuilds the heavily damaged refinery.

Depending on what it says, the Chemical Safety Board’s final report on the explosion could have consequences for similar facilities, including the Marathon Oil Corp. refinery in St. Paul Park. Its location on the fringes of the Twin Cities metropolitan area means that it puts up to 1.7 million people at risk, according to an EPA worst-case scenario.


Twitter: @_mattmckinney