The U.S. has begun a multimillion dollar cleanup of an airbase in Vietnam that the U.S. used during the Vietnam War to store the highly toxic chemical Agent Orange.

The launch Saturday of the $183 million program at the Bien Hoa airport, outside Ho Chi Minh city, comes more than 40 years after the end of the war. Bien Hoa was one of the main storage sites for the toxic formula.

The U.S. sprayed 80 million liters of Agent Orange over South Vietnam between 1962 and 1971 to deprive the Communist guerillas of tree cover and food.

The Agent Orange chemicals stored at Bien Hoa are believed to have seeped into the surrounding soil, sediment and rivers.

Agent Orange contains dioxin and has been linked to increased rates of cancer and birth defects across generations of Vietnamese.

In November, the U.S. completed a similar cleanup program at Danang airport that cost $110 million.

The amount of toxins at Bien Hoa is four times higher than the amount cleaned up at Danang.

Neither the United States government nor the manufacturers of the chemical have admitted any liability. Nor have they offered any compensation to Vietnamese affected by Agent Orange. U.S. military veterans have been compensated for exposure to Agent Orange since 1991.