In February, it was revealed that between 150 and 300 gallons of radioactive material might be seeping from the Hanford Nuclear Site's underground waste storage tanks.
This morning, the Tri-City Herald reports that the leak was probably discovered too late.
The cause of the leak most likely was flaws in the construction of the tank in the late '60s, but "the leakage could have been identified earlier by monitoring from more widespread access points," the report said.
The Department of Energy report also raised concerns about maintenance in the tank farms—groups of underground tanks holding radioactive waste—which date to as early as World War II.
The contractor is struggling with a backlog of maintenance to prevent and correct problems with aging infrastructure, the report said.