A landmark David-versus-Goliath legal battle is unfolding in the town of Shannon, Que.

In 2007, residents of the small community northeast of Quebec City won the right to seek damages in a class-action lawsuit against the federal government over the town’s contaminated water supply.

Now, a trial is underway with the potential for billions worth of damages on the line for 2,300 current and past Shannon residents.

The lawsuit alleges munitions manufacturer Industries Valcartier Inc. and the Department of National Defence were negligent in handling and disposing of trichloroethylene, or TCE, a known carcinogenic substance used at nearby Canadian Forces base Valcartier.

For 40 years, personnel at CFB Valcartier used TCE as a cleaning agent for cannons and other military hardware at the base.

In 2000, TCE was discovered in Shannon’s water wells. For years, residents unknowingly drank and bathed in water laced with the deadly toxic substance.

Around the same time, residents started to take note of an increasingly high rate of cancer diagnoses. 500 cancer cases were documented in Shannon, 200 of which proved fatal, an alarmingly high rate of disease for a town with a population barely 4,000-strong.

While legal counsel for the government dismissed residents’ claims for a lack of scientific evidence, Charles Veilleux, the lawyer representing the people of Shannon, will attempt to prove how exposure to TCE is directly linked to the high rate of cancer and illness in Shannon.