The incident happened on a highway exit ramp in Minnetonka.
It happened around 11 a.m., and police are actively investigating.
The Maplewood company has obtained a temporary injunction against the firm.
The Minneapolis incident occurred at Dowling Avenue and Bryant Avenue North
A tranche of analysis and data has been released by MN Community Measurement.
The health organization says it will change its procedures.
The explosion could be heard from 15 miles away, a neighbor said.