MONTREAL -- Quebec's environmental review board has concluded that exploiting the province's shale gas deposits is not worth the risk.

The agency's highly anticipated report -- released Monday -- stated there are too many potential negative consequences to the environment and to society from extracting natural gas from shale rock along the St. Lawrence River.

The report estimated that Quebec could receive between $71 million and $475 million a year, over 25 years, in royalties from shale gas extraction. However, the risks to air and water quality and potential increases in noise and light pollution are not worth the money, it said.

Moreover, the report noted that the risks associated with shale gas drilling are exacerbated due to the gas deposits being located in the densely populated area between Montreal and Quebec City.

It is unclear how the government will respond to the report or if it will extend a moratorium on shale gas exploration that has been in place since 2011.

Marie-Catherine Leduc, a spokeswoman for Quebec's environment minister, said the report "reveals many serious questions."

She added the government is aware of the concerns that Quebecers have about shale gas exploration.

"The department will take the time to analyze the report's conclusions with rigour," she said.

While the government's reaction to the report is still unclear, Greenpeace Canada said it knows exactly how environmental activists will react to the review board's findings.

"Every environmental group across the country will be waving this report in front of their provincial governments," said Keith Stewart, head of the organization's energy campaign.

He called the report "a clear indication" that provincial governments should reconsider exploiting unconventional fossil fuels.

Several provinces currently exploit shale gas deposits including British Columbia and Alberta.

Stephane Forget, vice-president of Quebec's federation of chambers of commerce, said the report's conclusions are "not very positive for the development of (shale gas) in Quebec."

However, he said the government should allow several wells to be drilled in order to show how the report's concerns can be addressed.

He added that the environmental review board didn't have enough expertise to properly evaluate the financial benefits of shale gas drilling in Quebec.

The federal government says Quebec has up to 300 trillion cubic feet of natural gas trapped in shale gas, but noted that only about 20 per cent to 30 per cent of the trapped gas is typically recoverable.

Shale gas is extracted commonly by using a method known as hydraulic fracturing, or "fracking."

Companies inject a pressurized fluid into a well bore, cracking open parts of the underground shale rock, releasing the previously trapped natural gas.

Quebec currently receives most of its natural gas from Alberta and the United States.

Several companies with shale gas drilling rights in Quebec did not return interview requests on Monday.