Ministers were facing growing pressure last night to investigate the safety and environmental impacts of drilling for shale gas after fears that it could have triggered two small earthquakes in Lancashire. Critics say the released gas can contaminate local water supplies and that seismic activity could be linked with the technique. They also argue that prospecting for shale gas – which is banned in France, as well as New York and Pennsylvania states – leaves a far worse carbon footprint than conventional gas drilling. Chris Huhne, the Energy and Climate Change Secretary, has given the controversial technique, known as \"fracking\", a clean bill of health and insisted it is already subject to \"robust\" controls. The Commons Energy Select Committee has also backed the procedure, arguing that Britain could have considerable reserves of shale gas that should be exploited to reduce the country\'s reliance on energy imports. But MPs of all parties told The Independent the time had come for government scientists to examine all the scientific evidence after signs that exploratory drilling could have caused tremors near Blackpool. The energy company Cuadrilla Resources has suspended its operations in the area to investigate any possible connection with its activities. The process of fracking involves injecting fluids at high pressure deep underground to blast apart rocks in which gas could be trapped. MPs last night demanded a thorough investigation by government scientists into the possible risks – and potential benefits – of fracking. Gordon Marsden, the Labour MP for Blackpool South, called on Mr Huhne to review all the evidence. \"I will be writing to the department to say that, in the light of the moratorium the company has placed on [shale gas] drilling, it would be helpful if it could look at the issues sooner rather than later,\" Mr Marsden said. He said the regulatory regime around the industry, which is still in its infancy in Britain, remained \"very underdeveloped\". He added: \"There remain questions to be answered about the viability of the process.\" Eric Ollerenshaw, the Conservative MP for Lancaster and Fleetwood, said he wanted to see \"real unbiased evidence about the pros and cons\" of shale gas drilling. \"We need a lot more information and a lot more public consultation,\" he said. Alun Cairns, the Conservative MP for the Vale of Glamorgan, said drilling should be suspended until the merits and potential dangers of the process could be considered.