YAKIMA, Wash. (AP) -- An underground tank holding some of the worst radioactive waste at the nation's most contaminated nuclear site might be leaking into the soil.
The U.S. Energy Department said workers at Washington state's Hanford Nuclear Reservation detected higher radioactivity levels under tank AY-102 during a routine inspection Thursday.
Spokeswoman Lori Gamache said the department has notified Washington officials and is investigating the leak further. An engineering analysis team will conduct additional sampling and video inspection to determine the source of the contamination, she said.
AY-102 is one of Hanford's tanks with two walls, which were installed years ago when single-shell tanks began leaking. Some of the worst liquid in those tanks was pumped into the sturdier double-shell tanks.
The tanks are now beyond their intended life span. The Energy Department announced last year that AY-102 was leaking between its two walls, but it said then that no waste had escaped.
At the height of World War II, the federal government created Hanford in the remote sagebrush of eastern Washington as part of a hush-hush project to build the atomic bomb. The site ultimately produced plutonium for the world's first atomic blast and for one of two atomic bombs dropped on Japan, and it continued production through the Cold War.
Today, it is the nation's most contaminated nuclear site, with cleanup expected to last decades. The effort - with a price tag of about $2 billion annually - has cost taxpayers $40 billion to date and is estimated will cost $115 billion more.
The most challenging task so far has been the removal highly radioactive waste from aging, underground tanks, some of which are currently leaking, and for the design and construction of a plant to treat that waste.
The Energy Department recently notified Washington and Oregon that it may miss two upcoming deadlines to empty some tanks and to complete a key part of the plant to handle some of the worst waste.
Here's the official statement from the Department of Energy:
The Department of Energy has been actively monitoring double-shell tank AY-102 since it was discovered to have a slow leak from the primary tank. On Thursday, June 20, 2013, workers detected an increased level of contamination during a routine removal of water and survey of the leak detection pit. Leak detection pits are routinely pumped to remove water and sediment. Then the pumps are surveyed for any radiological contamination.
The source of contamination is not yet verified, but may be an indication of a leak from the AY-102 tank’s secondary containment. However, further assessment must be completed before a determination can be made regarding the contamination source.
ORP has notified the Washington State Department of Ecology and U.S. Environmental Protection Agency, and convened an engineering analysis team to conduct additional sampling and video inspection to further assess the elevated radiation levels and determine the source of the contamination.
Here's the response from Gov. Inslee:
“Last night I received a call from United States Energy Secretary Moniz informing me that the US Department of Energy discovered what appears to be an elevated contamination level reading in the leak detection pit outside and adjacent to the Hanford double-shell tank AY-102. This is most disturbing news for Washington. It is not clear yet whether that contamination is coming directly from the outer shell of the AY-102 but it must be treated with the utmost seriousness. The discovery was made during a routine pumping outside the tank when pumps are also surveyed for radioactivity.
“The Secretary informed me that USDOE has convened an engineering analysis team to verify the source of the contamination through additional sampling and video inspection. It’s our understanding that this process could take several days.
“Our state experts confirm that there is no immediate public health threat. Given the relatively early detection of this potential leak, the river is not at immediate risk of contamination should it be determined that a leak has occurred outside the tank. The Secretary assured me that USDOE will respond swiftly and with all actions necessary to determine the condition of the AY-102.
"Prior to receiving this news from Secretary last night, he and I had held a productive meeting yesterday in OIympia, following his first tour of the Hanford site the previous day. Even before learning of this new development, I told the Secretary I continue to have serious concerns regarding the pace of addressing the leaking tanks. We will be insisting on an acceleration of remediation of all the tanks, not just AY-102. USDOE has a legal obligation to clean up Hanford and remove or treat that waste, and we ensure that legal obligation is fulfilled.”