At least 2,000 gallons of nitric acid were spilled Friday morning when a valve was knocked from a tank, briefly shutting down traffic along E. Hennepin Avenue in Minneapolis.
The spill at Hawkins Inc. leaked out of the company’s containment system and poured between 600 and 700 gallons of the acid into storm drains, said Fire Department spokesman Bryan Tyner.
“We have it contained and there are no life safety concerns,” Tyner said.
As far as hazardous chemical spills go, nitric acid is one of the easier ones for fire crews to handle, he said.
Firefighters were able to corral the highly corrosive acid within storm pipes by using containment booms, starting far enough away from the spill that no traces of the acid were found, and working their way in until it was spotted. Once found, crews neutralized the acid with soda ash and then flushed the pipes clean with water, Tyner said.
“The only product that we have found was right in the immediate area of the facility, so it doesn’t appear it was able to travel very far,” he said.
The company was evacuated as a precaution, but no injuries were reported.
The spill occurred when a valve was knocked off a 10,000 gallon stainless-steel tank, according to the Minnesota Pollution Control Agency (MPCA). Fire officials originally said that a total of 5,700 gallons spilled out of the tank. Richard Erstad, Hawkins general counsel, said it was closer to 2,100 gallons.
The acid flowed into a containment system, but the system apparently had a crack, which caused the leak into stormwater drains, Erstad said.
“We’ll obviously get that taken care of and make sure it doesn’t happen again,” Erstad said. “We just want to thank the city for their quick response.”
The company is a formulator, manufacturer, blender, distributor and sales agent for thousands of industrial chemicals. It has been responsible for several chemical spills of varying sizes over the past 20 years, said MPCA spokesman Walker Smith. The company’s spill response plan is up to date, he said.
Hawkins will be required to vacuum what’s left of the acid out of the storm pipes and continue neutralizing it before it is disposed.
The MPCA’s primary concern was making sure the acid didn’t make it to the Mississippi River, Smith said. Thanks in part to the weather, it didn’t.
“It just pooled up in the stormwater system and we were able to locate it,” Smith said. “There is almost no water in the system right now, but if it had been warmer and there was some snow melt …”
Nitric acid is a highly corrosive, strongly oxidizing acid. Fumes may cause immediate irritation of the respiratory tract, pain, and difficult or labored breathing.