The Australian company planning to build as many as 500 gas wells on thousands of acres in the north-west region denied yesterday it will use chemicals linked to cancer and tap water pollution.
According to the Irish Independent, Tamboran has been awarded the licence to make preliminary drillings for onshore natural gas in the Lough Allen basin, which takes in all of North Leitrim, and parts of counties Sligo, Roscommon, west Cavan and Donegal.
The volume of gas trapped in shale rock has been estimated to be worth tens of billions of euro.
Hundreds of people have been attending public meetings in the north-west where they were told huge stretches of water could be at risk of pollution from the project because of the controversial method of 'fracking' -- or hydraulic fracturing -- used to obtain the gas below the surface.
Fracking has come under scrutiny internationally due to concerns about environmental and health safety and has been suspended or banned in some countries, including France and parts of the US and Britain. The practice has also been blamed for causing earthquakes in the UK.
Fracking for underground gas was suspended recently near Blackpool after the operation caused mini-earthquakes.
Such tremors are caused when water pumped underground at high pressure has nowhere to go and effectively causes rock explosions, sometimes with a magnitude of 4.7.
A 2010 study by the US EPA "discovered contaminants in drinking water including: arsenic and copper adjacent to drilling operations which can cause illnesses including cancer, kidney failure, anaemia and fertility problems".
The EPA said a broad range of sources were being investigated, including agricultural activity, but noted gas drilling as a potential cause.
At an Oireachtas committee yesterday, Tamboran CEO Richard Moorman said the firm planned to construct as many as 500 gas wells, one every two to four kilometres, mainly in north Leitrim and Cavan, using one million gallons of water per well.
The company is also examining sub-structures in Bundoran, Mullaghmore, and Benbulben.
Mr Moorman insisted they would not use any chemicals to help force out the gas from the rocks below ground.
An Taisce chairman Charles Stanley-Smith called for a ban on fracking in Ireland and said the fluids used elsewhere "contain known and potential carcinogens".
"It was also linked to leaks of radioactive gases, contamination of water supplies, reproduction problems and damage to aquatic life, he told the Oireachtas Environment Committee.
Ciaran O hObain, principal officer at the Department of Energy and Natural Resources, told the committee such a project would have to be subject of an environmental impact report, as well as approval from the Environmental Protection Agency , local authorities, An Bord Pleanala, and the department itself.
He said natural gas production could start by 2019 if the project is approved.