Tank leak reported at Hanford nuclear waste site

The U.S. Department of Energy (DOE) announced April 29 that an underground chemical waste storage tank at the Hanford Site in southeast Washington is leaking. The department classified the leaking waste as “radioactive and dangerous.”

The Washington Department of Ecology’s Nuclear Waste Program, along with the U.S. Environmental Protection Agency, oversees DOE’s cleanup of the Hanford site.

“It’s a serious matter whenever a Hanford tank leaks its radioactive and dangerous chemical waste,” Washington Department of Ecology Director Laura Watson says. “Based on the information we have right now, the leak poses no immediate increased risk to workers or the public, but it adds to the ongoing environmental threat at Hanford.”

Tank B-109, which is at least 75 years old, is estimated to be leaking 3.5 gallons a day, or nearly 1,300 gallons per year.

The Department of Ecology has been concerned with this tank and tracking it for more than a year, when a formal leak assessment first began. B-109 is leaking into an area where other tanks have already leaked 200,000 gallons into the soil.

B-109 is miles away from the Columbia River, and the water table is 210 to 240 feet below the tank.

An estimated 1,700 gallons have leaked into the soil from B-109 dating back to March 2019.

Hanford tanks contain widely varying volumes of mixed waste (waste with both radioactive components and dangerous chemicals), each with a unique blend of constituents.

“This leak is adding to the estimated 1 million gallons of tank waste already in the soil across the Hanford site,” Watson says. “This highlights the critical need for resources to address Hanford’s aging tanks, which will continue to fail and leak over time.”

The Department of Ecology was notified about a year ago that the DOE had started a formal leak assessment for B-109. At that time, the DOE said the tank’s levels were decreasing but it was not sure why. The Department of Ecology has been tracking the situation and was notified April 29, that the DOE had determined that the tank is leaking.

The Department of Ecology has authority under the Tri-Party Agreement, which governs the Hanford cleanup, to take immediate action in response to a leaking single-shell tank only if it is “necessary to abate an imminent and substantial endangerment to public health or welfare or the environment.” 

The state’s initial assessment is that, while any leak is a serious issue, there isn’t an imminent danger.

The next step is for the Department of Ecology to try to reach agreement with the DOE about the best path forward. If the two agencies can’t agree, the Department of Ecology retains the authority to take an enforcement action and require specific actions to address the leak.