Minneapolis Sewer Explosion: Investigators Search For Cause

MINNEAPOLIS — State and city officials are still searching for the cause of a sewer explosion near the University of Minnesota campus in Minneapolis.

At about 3 p.m. on Thursday, officials said there was an "underground explosion" in the 1700 block of University Avenue. The 17th Avenue Residence Hall and nearby fraternities were evacuated, and students took up shelter in the Northrop Auditorium.

No injuries were reported. There was a strong gas odor that remained in the area following the explosion.

On Saturday, the State Fire Marshal’s office took over the investigation.

"We will continue to monitor the sewer system over the next few days, along with the cities of Minneapolis and Saint Paul, to ensure public safety," said Minnesota’s State Fire Marshal Jim Smith. "We also continue to investigate to find the source that is responsible for the discharge of a hazardous material into the system."

Smith added that "At this time, we think the situation has stabilized, but we remain vigilant."

Investigators have not found additional evidence of odors or high levels of flammable materials while monitoring the system.

Authorities also contacted communities on the path of the sewer corridor just north of Minneapolis urging them to be aware "of odors and reports of any person, business, or industry that may be depositing flammable materials into the sanitary sewer system."

The Twin Cities metro area wastewater collection and treatment system includes 640 miles of sanitary sewers and nine treatment plants.

Authorities are asking that residents in the area who smell gas call 612-624-COPS (2677).