People were evacuated from a water treatment facility in Columbia Heights Tuesday after two chemicals were accidentally mixed together and caused a dangerous reaction.

Employees notified the Columbia Heights fire department just after 1 p.m. that hydrochloric acid and caustic soda had been combined at the plant, according to John Larkin, assistant fire chief. When mixed, the two chemicals cause excessive heat and triggered the sprinkler system to go off in the building.

All employees were immediately evacuated and no injuries were reported, Larkin said, adding that the reaction was contained to the facility's hydrochloric acid room.

The official name of the plant is called the Minneapolis Water Works Treatment Plant, but the building is located on the 4400 block of Reservoir Boulevard in Columbia Heights.

As of late afternoon, members of the Minneapolis Fire Hazardous Material Team were reporting temperatures in the room had dropped and the sprinkler system was shutting down, Larkin said.

Larkin did not know how the chemicals were incorrectly mixed but said he thought it occurred through an automated process.
