The Latest: Evacuation area expands near Wisconsin refinery

This image from video provided by WDIO-TV in Duluth shows smoke rising from the Husky Energy oil refinery after an explosion Thursday morning, April 26, 2018 in Superior, Wis. Authorities say several people were injured in the explosion. (WDIO-TV via AP)
This photo provided by KQDS_FOX21 in Duluth, Minn., shows vehicles and personnel outside the Husky Energy oil refinery Thursday morning, April 26, 2018, after a tank containing crude oil or asphalt exploded at the large refinery in Superior, Wis. Authorities say several people were injured. The flame at the right is a normal part of refinery operations. (Natalie Froistad/KQDS_FOX21 via AP)
This photo provided by KQDS_FOX21 in Duluth, Minn., shows personnel outside the Husky Energy oil refinery Thursday morning, April 26, 2018, after a tank containing crude oil or asphalt exploded at the large refinery in Superior, Wis. Authorities say several people were injured. The flame at center right is a normal part of refinery operations. (KQDS_FOX21 via AP)

The Latest: Evacuation area expands near Wisconsin refinery

This image from video provided by WDIO-TV in Duluth shows smoke rising from the Husky Energy oil refinery after an explosion Thursday morning, April 26, 2018 in Superior, Wis. Authorities say several people were injured in the explosion. (WDIO-TV via AP)
This photo provided by KQDS_FOX21 in Duluth, Minn., shows vehicles and personnel outside the Husky Energy oil refinery Thursday morning, April 26, 2018, after a tank containing crude oil or asphalt exploded at the large refinery in Superior, Wis. Authorities say several people were injured. The flame at the right is a normal part of refinery operations. (Natalie Froistad/KQDS_FOX21 via AP)
This photo provided by KQDS_FOX21 in Duluth, Minn., shows personnel outside the Husky Energy oil refinery Thursday morning, April 26, 2018, after a tank containing crude oil or asphalt exploded at the large refinery in Superior, Wis. Authorities say several people were injured. The flame at center right is a normal part of refinery operations. (KQDS_FOX21 via AP)