SUPERIOR, Wis. (KMSP) - Wisconsin Governor Scott Walker toured the Husky Energy oil refinery in Superior days after an explosion at the site.
More than a dozen people were injured and thousands of residents were evacuated when the refinery went up in flames on Thursday.
The fire burned for several hours before crews were finally able to put the flames out later that evening.
Governor Walker says both federal and state agencies are working to make sure the water and air quality are safe.
"Our professionals from the Department of Natural Resources continue to monitor both surface water and runoff issues as the cleanup continues just to make sure that's all safe as well and the appropriate processes are being used to be involved in the cleanup itself with this site," said Gov. Walker.
Husky Energy officials say they'll be looking at ways to improve the refinery, adding that they may replace the hydrogen fluoride chemical used at the site.