The dismissal of a case in the United States that accused chemical companies of war crimes by supplying the U.S. military with Agent Orange in the Vietnam War triggered angry protests from Vietnamese victims on Friday.

“His verdict is completely unreasonable and unjust,” Nguyen Trong Nhan, vice president of Vietnam’s Association of Victims of Agent Orange, told AMN Health a day after U.S. District Court Judge Jack Weinstein dismissed the case.

“We will pursue the suit until justice is done,” Nhan said.

The civil suit was based on allegations by Vietnamese that they were injured and their land left barren by the U.S. use of Agent Orange and other herbicides from 1965 to 1971.

More than 30 companies were named in the lawsuit, among them Dow Chemical Co. and Monsanto Co.

“Judge Weinstein has made it easier for our country to continue to evade moral responsibility for the consequences of its actions,” John McAuliff, executive director of the New York-based Fund for Reconciliation and Development, said in a statement.

The suit said up to 4 million Vietnamese people suffered from dioxin poisoning due to Agent Orange, a defoliant dumped by U.S. warplanes on Vietnamese jungles to destroy sources of food and cover.

Dioxin can cause cancer, deformities and organ dysfunction.

U.S. forces sprayed an estimated 20 million gallons of herbicides, including Agent Orange, on Vietnam during the war but the chemical remained in the water and soil decades later.

Weinstein said the evidence of injuries in the case was presented in “brief anecdotal form”, and “the fact that diseases were experienced by some people after spraying does not suffice to prove ... that the harm resulted to individuals because of the spraying”.

The case had been closely watched as a test of the reach of U.S. courts as it considered the power of the U.S. president to authorise use of hazardous materials during war.

The chemical companies argued they produced Agent Orange according to U.S. government specifications and there was no proven connection between Agent Orange and the health problems it is accused of causing.

Other companies named in the lawsuit included Hercules Inc., Occidental Chemical Corp., Ultramar Diamond Shamrock Corp., Maxus Energy Corp., Uniroyal Inc. and Wyeth.