File Photo: In the early morning hours of Oct. 9, 2010, three structures at Hanford's 300 Area came crashing to the ground as planned. The explosive demolition of the 309 Building stack, 337 Building and 337B Building capped months of work by Washington Closure Hanford and subcontractor staff. The stack was 110 feet tall, the 337B Building was 93 feet tall and the 337 Building was three stories tall. (Credit: U.S. Department of Energy's Office of River Protection)

SAN FRANCISCO, Sept. 19 (Xinhua) -- The northwest U.S. state of Washington said Wednesday that the federal government has agreed to pay 925,000 U.S. dollars to improve workers' safety at the country's most polluted nuclear waste site in the state.

Washington State Attorney General (AG) Bob Ferguson told reporters in Seattle that the U.S. Department of Energy (DOE) will conduct testing and implementing a new system to treat or capture hazardous tank vapors at the Hanford Nuclear Reservation in the next three years as part of a settlement agreement between the state and the DOE.

The agreement "marks the first time in the history of the Hanford Nuclear Reservation that Energy will destroy or capture tank vapors at their source, thereby eliminating the hazard to workers," Ferguson said in a statement.

The settlement accord requires the DOE to pay nearly 1 million dollars in fees and costs to Washington state and Hanford Challenge, an advocacy group that has fought for decades to protect the safety of the workers at the Hanford nuclear waste site.

Ferguson filed a lawsuit in 2015 against the DOE and its contractor Washington River Protection Solutions LLC to seek better protection for the workers after 20 years of the employees getting sick from vapor exposure.

The tanks at the Hanford site contain more than 50 million gallons (204 million liters) of radioactive and chemical wastes left from the past production of plutonium for the nation's nuclear weapons program.

"The health risks are real, and the state is taking action today to ensure the federal government protects these workers now and in the future," he said when he filed the state.

Ferguson called on Twitter Wednesday's agreement "a big win for workers" as the federal government has agreed for the first time to test a new technology to tackle the nuclear problem, including destroying tank vapors and installing a vapor monitoring, detection, and alarm system in the areas where vapor exposures are most likely to occur.

The 943-square-kilometer Hanford nuclear site is located along the Columbia River in Eastern Washington state. It produced more than 70 percent of the plutonium for the U.S. nuclear arsenal since it was built in the Second World War.