Attorneys for a group of Vietnamese claiming they have been poisoned by the Vietnam war-era defoliant Agent Orange have taken their case against the manufacturers to the federal appeals court. Speaking to VOA Monday, the lawyers said the companies knew their products were dangerous. Victoria Cavaliere reports from VOA's New York bureau.

U.S. warplanes sprayed about 70 million liters of Agent Orange on Vietnamese forests between 1962 and 1971. The poison, which contains dioxin, was meant to destroy sources of food and foliage cover. Civilians who came into contact with the chemical say it has caused illnesses like cancer, birth deformities and organs dysfunction.

In 2004, Vietnamese victims filed a suit in a federal court in New York against more than 30 companies, including Dow Chemical and Monsanto. They claimed the companies knew Agent Orange was toxic, but still supplied it to the U.S. military in order to make a profit. The trial court dismissed the lawsuit.

A lawyer for the plaintiffs, Jeanne Mirer, says many people are still falling ill or experiencing birth defects more than 30 years after the war. She says the companies should be held to account.

"Poison was in that mixture, in those agents," said Jeanne Mirer. "The chemical companies knew it was there and didn't take the time to remove it, even knowing that it was going to be sprayed on large areas of Vietnam."

Mirer says she and her colleagues told the appeals court in a hearing held last week that Agent Orange violated international laws banning the use of poisoned weapons.

"We feel strongly that the use of these weapons were illegal that the time and that the chemical companies knew how they were going to be used," she said.

Lawyers arguing on behalf of the chemical companies say Agent Orange is an herbicide, and its use did not violate international law because it is not a poison specifically designed to harm or kill people. The attorneys also said that a court ruling in this case could infringe on battlefield decisions made by the U.S. military.

Dow Chemical told VOA that 40 years of research has not produced concrete evidence that Agent Orange causes illness. The company also says it is not responsible for the manner in which its products are used by the military.

In 1984, U.S. veterans of the war received some compensation from the chemical companies for exposure to Agent Orange.