The federal government and two chemical companies went to court Wednesday in a bid to stop a class-action lawsuit launched by people who claim they developed cancer after being exposed to Agent Orange at Canadian Forces Base Gagetown in New Brunswick.

The suit, brought by more than 1,700 people from across the country as well as 35 from the province, was certified in the Supreme Court of Newfoundland and Labrador trial division.

On Wednesday, lawyers representing federal Attorney General Rob Nicholson, Minister of National Defence Peter Mackay , the Dow Chemical Company and the Pharmacia Corp. were in a St. John's courtroom seeking to have the certification order overturned.

Retired Canadian soldier, John Mallard, says he was diagnosed with cancer because of Agent Orange at CFB Gagetown. (CBC)

The plaintiffs say they have been diagnosed with cancers including leukemia, Hodgkin's disease and non-Hodgkin's lymphoma because of their exposure to Agent Orange at Gagetown between 1956 and 2004.

"All the time I was at Gagetown was out in the field training — you're sleeping on the ground, you are eating your hard rations … you're eating with your hands, so basically you're ingesting it," said retired soldier John Mallard, who is convinced his cancer stemmed from exposure to the herbicide at Gagetown."You're sleeping in it, you're burning bush to keep warm, so you're inhaling it."

Retired brigadier-general Ed Ring, a Newfoundlander and another of the plaintiffs, was outraged by the bid to stop the suit.

Retired brigadier-general Ed Ring, of St. John's is a member of a class-action suit claiming exposure to Agent Orange left him with cancer. (CBC)

"I am appalled that we have large organizations like the federal government and these chemical companies trying to deny us the opportunity to even have our case heard in court," he said.

The federal government and the companies maintain Agent Orange — a herbicide developed in the United States for use in the Vietnam War — was only one of 23 chemicals sprayed on the base, so there is no way to determine who was exposed to which chemical and for how long.

They also say there's not enough common ground among the ailments suffered by the plaintiffs to justify a class-action suit.

In September of 2007 the federal government announced a $96-million compensation package for people exposed to the herbicide at Gagetown —a $20,000 payout to anyone who qualified for it.

Members of the class-action suit refused to accept the settlement.

Hearings are scheduled to continue in St. John's Thursday.