A new report by the U.S. Department of Energy's Inspector General found that design changes at the new Hanford Nuclear Reservation vitrification plant were not properly verified.

The audit released Thursday was highly critical of the design change process at the troubled $12.2 billion vit plant. The facility is designed to convert about 56 million gallons of dangerous radioactive waste into a glasslike substance for eventual burial.

The audit said contractor Bechtel National Inc. was required to ensure the vitrification process is safe for workers, the public and the environment, but failed to do that in the design change process.

Hanford was created by the Manhattan Project during World War II in the race to build an atomic bomb.