The mayor says people with confirmed COVID-19 cases went to multiple businesses.
He was convicted last year of leaving the scene of an accident.
Superior Mayor Jim Paine made the announcement Tuesday morning.
The Nemadji River appears to have crested Tuesday morning.
The explosion happened around 10:50 a.m. Sunday.
The 40-year-old was reported missing late Monday, April 22.
He was last seen leaving a residence on Saturday evening.
The crash happened Monday morning on icy roads.
It's estimated to have caused around $10 million worth of damage.
A worn valve was behind the disaster.
An oil spill response team has been working with the refinery.