Minnesota lawmakers ask for meeting on refinery explosion

U.S. Rep. Betty McCollum has asked the federal Chemical Safety and Hazard Investigation Board to hold a public forum in the Twin Ports of Duluth and Superior, Wis., in early fall, citing "serious questions about the safety of U.S. refineries using hydrogen fluoride" in the wake of an explosion and fires at the Husky oil refinery in Superior in April.

U.S. Rep. Rick Nolan, U.S. Sens. Amy Klobuchar and Tina Smith, and Wisconsin Sen. Tammy Baldwin also signed the letter Wednesday.

The accident on April 26 caused an enormous smoke plume, and forced the evacuation of thousands of people in a zone extending 10 miles south of Superior and three miles to the south and east.

The Chemical Safety and Hazard Investigation Board is currently investigating the incident. In a preliminary report released in August, investigators say a failed valve caused the initial explosion.

Debris flew about 200 feet, puncturing a large storage tank, spilling more than 15,000 barrels of hot asphalt, which ignited a major subsequent fire.

The debris did not damage a tank about 150 feet away, containing 15,000 pounds of hydrogen fluoride, a highly toxic chemical that's used to make higher-octane gasoline. It's an acid that can cause lung damage when people are exposed to it.

"Had Twin Ports residents been fully informed about the risk of the HF stored at the refinery prior to the incident, it is likely that emergency evacuations would have been implemented more urgently," McCollum wrote in the letter.

A recent report found that social media caused confusion for emergency crews trying to evacuate people.

She added a public forum would allow for community input about the scope of the Board's investigation, and would also provide for public dialogue explaining "the Board's stated grave concerns about the use of HF in urban oil refineries."

A 2011 report from the Center for Public Integrity said hydrogen fluoride is used by 50 out of 148 refineries nationwide, including a refinery operated by Andeavor in St. Paul Park, Minn.

After the explosion, Duluth Mayor Emily Larson and Superior Mayor Jim Paine both asked Husky Energy to stop using the chemical at the Superior refinery.

Husky has said it will take up to two years to rebuild the refinery and for normal operations to resume.

Chemical Safety and Hazard Investigation Board spokesperson Hillary Cohen said the board is currently reviewing the letter and hopes to have a plan on how they will be moving forward in the next few days.