Tests reveal diesel fuel poured into sewer pipes under UMN campus as investigation continues

MINNEAPOLIS -- Results from chemical tests on Wednesday confirmed that diesel fuel was the substance most likely poured into the sanitation sewers flowing underneath the University of Minnesota's campus.

According to investigators, there was enough fuel to release highly combustible vapors across a nearly mile-wide corridor, prompting evacuation orders in dozens of buildings and a three-alarm emergency response.

"It was good that we determined that it was diesel, but diesel is so common it didn't narrow it down enough," State Fire Marshal Jim Smith explained to WCCO. "We still have a large footprint to check out where it's coming from."

The Metropolitan Council is leading the investigation into how the diesel entered the sanitation pipe system, the second such incident on the U's campus in three months. 

Smith says unlike stormwater drains that flow from streets and neighborhoods into spillways and rivers, sanitation pipes are an underground system of moving wastewater from toilets, sinks, showers and utility rooms, among other indoor areas.

"And to trace back where it came from, if it's done behind closed doors, it's very difficult," Smith lamented.

In a news release sent Wednesday, the Met Council noted investigators are trying to determine whether the diesel was dumped into the City of Minneapolis sewer system or the regional system, which is owned and operated by the Metropolitan Council - and both showed signs of a "black oily liquid or odor." 

These lines connect downstream and end up at the Metropolitan Wastewater Treatment Plant in Saint Paul.  

"The voice in back of my head also has an anger knowing this has happened twice, and if this is done intentionally then that's extremely irritating to me because a lot of lives are in jeopardy when something like this happens," Smith added. "I wish I could sit here now and reassure everyone that it's not going to happen again but right now until we find the source and the reason why, I can't guarantee the citizens that."

The Met Council is asking anyone with information about a large disposal of a hazardous material into the sewer system to contact the Met Council at 651-602-4511 or the Minnesota Duty Officer at 651-649-5451. Anyone who smells gas or chemical odors should call 911.