The environmental impacts of intensive hydraulic fracturing for natural gas extraction are not well understood and could pose a threat to B.C.’s ecosystems, according to a scientific review led by Simon Fraser University researchers.

Poor regulation and a lack of disclosure of methods and the chemicals injected into the ground in jurisdictions where hydraulic fracturing is widely practised have left huge “knowledge gaps” about the consequences of the process popularly known as “fracking”, said SFU conservation biologist Viorel Popescu.

Fracking involves the injection of a cocktail of water, chemicals and sand into shale formations under high pressure, which fractures the rock deep underground and releases otherwise inaccessible gas. The aqueous mixture may include methanol, xylene, naphthalene, hydrochloric acid, toluene, benzene, and formaldehyde, as well as proprietary chemicals, some of which remains in the ground after the process is complete, according to the article published on Thursday in the peer-reviewed journal Frontiers in Ecology.

Thousands of wells may be required to extract gas from a large shale formation.

Little research has been done on the impacts of fracking on groundwater and ecosystems, meaning B.C. is about to embark on a massive expansion of the gas industry with unknown consequences, Popescu said.

Premier Christy Clark has made expanded natural gas extraction central to her government’s economic plan, promising thousands of jobs and billions of dollars in revenue. The ambitious plan includes the construction of up to five LNG plants in northern B.C. to process gas for export to Asia.

Fracking for shale gas has been practised in the United States for more than 60 years — at least a million times, according to the Society of Petroleum Engineers — but states vary widely in their regulation of the process, disclosure of the chemicals used and environmental impact reporting.

The Canadian Association of Petroleum Producers supports disclosure of fracking fluid additives — required by law in B.C. — but the industry is relatively new here, so the effects of additives are not well-understood.

“In the 24 states with active shale gas reservoirs, each has its own mandate and regulations and may not require proprietary chemicals to be disclosed,” Popescu said. “In Canada, there appears to be more transparency.”

Only five of those states maintain public records of accidents and regulatory violations, so the frequency and severity of contamination events associated with fracking is not known.

In B.C., fracking water that returns to the surface is recovered for reuse or injected into exhausted gas wells for disposal. Surface disposal is prohibited.

“We need more than just disclosure of the chemicals,” he said. “We need to know what we are putting in the ground, how much stays there and how it migrates, which is one of the big research unknowns.”

B.C. requires steel and casing and cement to a depth of 600 metres in natural gas wells to provide isolation from groundwater, and so far has never had a reported incident of water contamination due to fracking, according to the ministry of natural gas development.

rshore@vancouversun.com