Quebec says it will give Reliance Power Equipment one more day to submit a cleanup plan for PCBs it has illegally stored in Pointe Claire for the past 15 years.

The provincial government and the City of Pointe Claire had initially set a midnight deadline on Wednesday, which has since expired.

The Liberal MNA for Jacques-Cartier, Geoff Kelley, says his constituents in Pointe-Claire deserve more information about how the cleanup will proceed.

Kelley says it's not enough for the environment ministry to tell citizens that it will take over the cleanup if the company does not come up with an acceptable plan.

"Is it a question of weeks? Is it a question of months? How long will it take?" Kelley asks. "What exactly will be done? These are the questions that the neighbours to the site are asking."

Kelley also called on Environment Minister Yves-François Blanchet to visit Pointe-Claire personally to reassure residents.

"In the new world of social media, if you don't have reliable information, rumours circulate…Lac St-Louis is polluted and things like this," Kelley said.

At a midnight press conference, Pointe Claire Mayor Bill McMurchie said he wouldn't accept any more delays.

"The city council of Pointe Claire insists on behalf of Pointe Claire citizens that immediate action be taken by the [environment ministry] and considers unacceptable any additional administrative delay," he said.

But Environment Minister Yves-François Blanchet says even though he'd rather not offer an extension, he has no choice.

"It's a matter of law…we have to provide them with the minimum delay to provide us with an answer to do exactly as we ask."

Blanchet says he doubts the extension will make a difference.

The company has until 10:25 a.m. Friday to submit its action plan.

Up to 1,200 litres of oil containing PCBs leaked

Ministry officials said they have been negotiating with Reliance Power Equipment for weeks to to clean up the site, to no avail.

The environment ministry confirmed Tuesday that it had investigated the leak of 800 to 1,200 litres of oil containing PCBs (polychlorinated biphenyls) that had spilled on the company's West Island property in March.

Ministry officials are expected to arrive on the site on Friday to begin securing the area. The City of Pointe Claire will continue to monitor the site until then.

The company has not responded to CBC's requests for an interview.

Who will pay?

It's estimated the cleanup will cost between $2 and $2.5 million.

If the company does not submit an action plan, the environment ministry will take over the work, which could take months.

The environment minister says Reliance Power Equipment will be billed for the work.

The dangers of PCBs

McGill environmental assessment expert, Michel Bouchard, says PCBs are volatile and present a serious health risk.

"The real danger is combustion, either accidental fire or…[arson] by somebody who would want to do something bad," Bouchard says. 

If the contaminated area caught fire, smoke carrying the PCBs could spread to outlying areas, including Montreal.

PCBs were once used as a coolant and insulating fluid.

The import, manufacture and sale of PCBs were made illegal in Canada in 1977.

However, Canadian legislation has allowed owners of PCB equipment to continue using the equipment until the end of its service life.

In 1988, 500 barrels of oil laced with PCBs exploded at a warehouse St-Basile-le-Grand, sending plumes of smoke across the region and forcing residents to flee.