An investigation is underway following a pipe explosion last month at the Hanford site's Plutonium Finishing Plant.
A spokesman for the CH2M Hill Plateau Remediation Company says the employees were cutting a pipe on April 17th when they heard a loud bang and witnessed a small flame emit from the end of the pipe.
The pipe being cut was sealed within a containment area and no employees were hurt.
Further inspection of the pipe showed no signs of any spread of contamination.
Employees at the Plutonium Finishing Plant have stopped using mechanical methods used until a cause is determined.