Fracking has sparked controversy in Nova Scotia. CBC

An engineering professor from Cornell University urged Maritime governments to be cautious about shale gas development.

Tony Ingraffea, who has a Ph.D. in rock fracturing mechanics, told delegates at the "Protecting our Communities: A Conference on Shale Gas and Fracking" conference in Truro, N.S., on Saturday that there is no reason to rush into shale gas drilling.

Ingraffea said there is still much that science doesn't know about the process, but the fact that it causes groundwater contamination is not in doubt.

In Nova Scotia, the Dexter government announced a review of its regulations regarding shale gas development in April.

Ingraffea said it could take 10 years to collect enough data to determine the safety of hydro-fracking.

"There will be contamination incidents," he said.

"The question is: how many, at what rate should we expect them over space and time and what will be the environmental, human health and financial costs?"

Ingraffea said shale gas will only increase in value over the coming years and waiting to extract it will avoid any pitfalls in the still-developing extraction process.

"There's no logical reason other than political reason for Nova Scotia to join the experiment. Let it play out where it's ongoing," he said.

"Let the science continue to evolve. Let the technology continue to evolve and get to a point … four to five, maybe even 10 years from now, when adequate science has been done and the cumulative impact of all this activity on the environment, human health and climate can be scientifically assessed."

The Truro conference was a gathering of citizens, activists and experts sponsored by NOFRAC, the Ecology Action Centre, the Council of Canadians and the Canadian Association of Physicians for the Environment.

Fracking has been a controversial issue in Nova Scotia and New Brunswick, where numerous groups and communities have come forth to oppose shale gas exploration.

Ingraffea was a researcher with the oil and gas industry for 25 years, where he specialized in hydraulic fracture simulation. He was invited to speak to the Parliamentary Standing Committee on Natural Resources about shale gas in February 2011.