Campaigners are calling for a ban on the extraction of "shale gas" in the UK until potential environmental and human health risks have been properly assessed.
Exploitation of the natural gas in this country is expected to begin near Blackpool later this month, but the Co-operative has raised concerns the process of extraction can contaminate groundwater.
In the US, some residents in areas where drilling for shale gas is taking place can set fire to their drinking water and have become ill because of pollution by gas and chemicals, according to a new documentary Gasland.
The gas is found in shale formed from deposits of mud, silt, clay and organic matter.
It is extracted by drilling down and then horizontally through the ground and then by "fracking", a process of hydraulic fracturing of the shale using high pressure liquid containing chemicals to release the gas.
According to a report by the Tyndall Centre for the Co-operative, information about which chemicals are involved in the process is not publicly available but data on what is being stored at drilling sites in the US indicate the use of chemicals which are toxic or cause cancer.
The Co-operative, which is running a campaign against "unconventional" fuels such as tar sands from Alberta, Canada, which are a much more polluting source of oil than conventional oil, has also raised concerns about whether the gas fits with a move to a low carbon economy.
While shale gas does not emit much more carbon in its production and use than conventional natural gas, its exploitation worldwide could add to the greenhouse gases already being released.
The Co-operative is calling for a moratorium on exploitation to allow the wider environmental concerns to be addressed.