Chemical Safety Board Reveals Latest in Husky Refinery Explosion Investigation

The explosion investigation is ongoing.

SUPERIOR, Wis.- After demands from concerned Twin Ports citizens and politicians, the Chemical Safety and Hazard Investigation Board (CSB) is continuing its review process of the Husky Explosion and fire.

The board gave an initial investigation and update back in august. The second update and public hearing happening Wednesday in Superior.

“The CSB is committed to a transparent investigation so that you call can understand what happened here and how it can be prevented from happening again,” CSB interim exec. of the board Kristen Kollinasky said.

Before hundreds the CSB presented its latest investigation finding the cause of the Husky refinery explosion and subsequent fire this past April.

Investigators are comparing the Superior explosion to a similar refinery explosion that happened in Torrance, California in 2015 where an eroded valve failed in keeping hydrocarbon and oxygen separate, causing a reaction in what is known as a fluid catalytic cracking unit (FCC).

In both California and Superior, investigators believe the FCC was the starting place of the explosion.

“The FCC unit is very important in the production of gasoline in any refinery existent, a lot of times they’re really the driving engine at a refinery to help create gasoline and kind of that octane level product,” chief investigator Mark Wingard said.

Investigators have yet to declare the slide valve at the Husky refinery to be the ignition cause in what they call the “fire triangle”

“You need to have three things to have a fire. You need to have a fuel, which in this refinery case would be the hydrocarbons, you need to have oxygen and you need to have an ignition source,” Wingard said.

The continued use of slide valves is one of several questions being considered by CSB investigators. The layout of the husky refinery is also being studied. Including whether changing that set–up is possible during husky’s rebuild.

“I feel like taking a look at facility siting is certainly important and definitely something we’re looking into in this investigation,” Wingard said.

After an update from the CSB, citizens were given the chance to share their thoughts on the Husky explosion. The most common concerns being the refinery’s continued use of hydrogen fluoride and the location of the refinery if something like this were to happen again.

“The shrapnel that hit the asphalt tank, could have also hit the hydrogen fluoride tank since it was in the same proximity,” Ginger Juel said.

“So we want to make sure that the chemical safety board is really digging deep in the issue of hydrogen fluoride in our community.”

Juel was in the group who called for the CSB meetings.

When asked to comment on the presentation given by the CSB and the progress of the refinery’s rebuild, Husky had this to say in an email:

“We’ve appointed an engineering contractor to oversee design work for the rebuild and as part of that process, we continue to evaluate options around the use of hydrogen fluoride.”

Those who are interested in making comments to the CSB, but could not attend the hearing, can do so by emailing

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