Energy giant Cuadrilla are calling for fracking earth tremor limits to be reviewed if it is to continue work at its Preston New Road site.
Since December the company has been assessing the results of its fracking at the Preston New Road site in Lancashire, which triggered 57 small tremors before Christmas, some above the 0.5 magnitude (ML) safety limit at which fracking has to be paused for 18 hours.
No fracking has taken place on the site since December.
Speaking this afternoon, Cuadrilla said it has asked the Government to review the 0.5ML limit to allow fracking to continue at the site.
A spokesman said: "Cuadrilla confirmed that it has requested the Oil and Gas Authority (OGA) to urgently review the TLS to enable the Preston New Road exploration wells to be properly tested and produced effectively, without compromising safety or environmental protection.
"Subject to the outcome of such a review Cuadrilla plans to complete hydraulic fracturing of the PNR1 well, fracture the PNR2 well and carry out flow testing of both wells later this year."
They added that "an intentionally conservative micro-seismic operating limit" of 0.5ML had "severely constrained the volume of sand that could be injected into the shale rock".
They continue: "Cuadrilla has now shut in the well and will monitor build-up as it continues to assess the results."
Earlier this week energy firm Ineos urged the Government to raise "absurd" limits on fracking which it said were making the UK's shale gas industry "unworkable".
Chairman Sir Jim Ratcliffe said: "We have a non-existent energy strategy and are heading towards an energy crisis that will do long term and irreparable damage to the economy, and the government needs to decide whether they are finally going to put the country first and develop a workable UK onshore gas industry."
In response to Cuadrilla's announcement, John Sauven, Executive Director of Greenpeace UK, said: "Cuadrilla have practically admitted that they can't make fracking work under the safety rules they've been boasting about for years.
"If they can't, then they shouldn't. In order to ‘grasp the prize’ of a very small amount of very expensive fracked gas, ministers have already removed people's property rights and are pushing plans to suppress all local democratic control by allowing fracking without planning permission.
"And now the industry need just one more regulation to be lifted, the safety limit on earthquakes.
"Until the next one, of course. The UK government should stop wasting time on this polluting industry and back the clean energy infrastructure we need to tackle climate change."
And in January Cuadrilla welcomed reports from two scientists that suggest increasing the tremor limit at drill sites could be done safely.
Dr Ben Edwards, of Liverpool University, who worked on a recent report suggesting 1.5ML tremors were the same level as dropping a melon, and British Geological Survey scientist Dr Brian Baptie, who contributed to the report on Cuadrilla’s Preese Hall fracking in 2011 which caused two larger tremors, and led to the recommendation of the 0.5ML limit, have now said that the limit could be raised safely to 1.5ML, which “was unlikely to be felt”.
Cuadrilla's Chief Executive Officer Francis Egan said: “Cuadrilla and its investors remain committed to this opportunity.
"The potential for Lancashire and the UK has again been clearly demonstrated by the fracturing and flow-testing carried out at Preston New Road. We look forward to completing the job."