Two men were treated for injuries Tuesday afternoon after anhydrous ammonia started leaking when a cylinder was being changed at a south Missoula business Tuesday afternoon.
"In the process of changing (a 100-pound cylinder), they had a valve that malfunctioned on them and allowed the anhydrous ammonia to leak," said Nate Nunnally, assistant fire marshal of the Missoula City Fire Department.
An employee of Thompson Dental Manufacturing Co., who was trying to change the cylinder, and a manager were exposed to the chemical. The two were treated by Missoula Emergency Services at the scene, then taken to St. Patrick Hospital, Nunnally said.
"The inherent problem is when you're in an enclosed area, it can be caustic," said Nunnally, who did not know the employee's condition.
Members of the Regional Hazardous Materials Response Team were called and, after donning special safety gear, entered the business and determined that the substance, which is lighter than air, had dissipated.
Residents in a one-block radius of the 1201 S. Sixth St. business were evacuated and area streets were cordoned off for more than two hours after the 2:10 p.m. incident.