The party’s Blue Mountains candidate Kerrin O’Grady and Penrith’s Suzie Wright issued a joint statement last week saying they were very concerned over applications from Apex Mining and Peabody Resources to explore for coal seam gas in the Warragamba catchment.

“The 2009 proposal to conduct exploratory drilling under huge sections of Blue Mountains World Heritage Area could be resurrected and the potential for contamination of our underground aquifers, and in the case of the Warragamba catchment, Sydney’s drinking water supply, are very real,” Ms O’Grady said in the statement.

“These mining companies don’t undertake exploration without a high probability of extraction. Once approved and mining begins, it is too late.”

Mining would involve the controversial “fracking” technique, which involves drilling into coal seams and injecting under high pressure, water containing chemicals to break up — or “frack” — the coal seam, Ms Wright said.

Gas — usually methane and hydrogen — is then extracted from the well, and some of the water is extracted and stored in open ponds onsite.

However, Ms Wright said laws and regulations pertaining to the environmental and social impact of both water contamination and the mining techniques were “inadequate”.

“This form of mining puts our waterways and ecosystems at risk of irreversible contamination,” she said.

Both candidates are calling for a moratorium on all current coal seam gas exploration and extraction in the area.

“The old political parties need to say where they stand on coal seam gas exploration and mining along the escarpment,” Ms Wright said.

“Will they allow this to take place in future? The Greens will say no to coal seam gas mining.

“Coal seam gas mining carries huge risks for the environment. One well injects up to 500,000 litres of water mixed with highly toxic chemicals into the coal seam, fracturing the rock structure. This high-pressure injection fractures the seam and forces the methane gas to escape.”

The Blue Mountains and Nepean Greens have called on the two major parties to declare their policies to keep Sydney’s drinking water supply secure and will be screening the film Gaslands, which deals with the billion-dollar energy industry, at Glenbrook Theatre on February 13 as part of their awareness campaign.

Greens NSW upper house MP Cate Faerhmann will speak on the night, which begins at 6pm. All are welcome, for more details contact Ms Wright on 0468 832 356.