Residents of a small town in Quebec are asking Ottawa for millions of dollars in compensation to deal with groundwater contaminated by toxins used at a nearby military base.

The federal government has already spent more than $30 million trying to find the town of Shannon, Que., a new water source after tests showed the existing source was contaminated by trichloroethylene, or TCE, a metal degreaser.

Health Canada describes TCE as being "probably carcinogenic to humans."

The tests showed the chemical had infiltrated the area's water table. TCE was used for decades on the Valcartier military base, about 25 kilometres south of the town.

Shannon residents have launched a class-action lawsuit against the government, set to be heard in the fall. Principal claimant Marie-Paul Spieser wants Ottawa to contact the hundreds of families who have lived near the base since the 1940s and to have them tested for contamination.

"I'm worried… for the health of the citizens," she said. "I'm really worried."

The suit asks the government to pay what could amount to millions of dollars in compensation to those who developed cancer and other illnesses over decades of exposure. Last month, the federal government announced it would spend $13.3 million to build a new sewer system in Shannon.

Local activist Jean Bernier went to Parliament Hill on Wednesday to hand in a petition signed by 23,000 local residents to urge the government to pay for a major cleanup.

"We have a lot of military personnel [and] civilian people that only live in Shannon that died," he said.

"We have the scientific proof — we're up to 13 different cancers that can be caused by TCE."

The petition also aims to support an upcoming bill to be presented by Bloc Québécois MP Christiane Gagnon.

The bill, if passed, would force the federal government to contact all those who may have ingested contaminated water since the 1940s.