British chemical manufacturer Ineos has called on the U.K. government to change its ‘unworkable’ rules on gas fracking which it says could force the closure of the industry.

Ineos has the largest shale gas license acreage in Britain and wants to develop the sites to cut its reliance on imported gas, which it says will dramatically reduce its costs.

“The Government is shutting down shale by the backdoor and is betting the future of our manufacturing industry on windmills and imported gas,” Ineos said in a statement on its website.

Ineos said Britain must change its so-called traffic light seismicity regulations which mean fracking must be halted for 18 hours if seismic activity of magnitude 0.5 or above is detected at sites.

“Ineos calls upon the Government to either make shale workable or shut it down,” Ineos said.

Cuadrilla, currently the only company to have fracked for gas in Britain, had to halt operations several times last year at its Preston New Road site in northwest England due to seismic events which exceeded the limit.

It has also said the current regulations are too stringent and experts agree that the limit for tremors could be safely raised at fracking sites.

However, the government, which initially supported fracking to cut Britain’s reliance on imports as North Sea gas supplies dry up, said earlier this year it has no plans to change the rules.

Britain currently imports around 60% of its gas needs via pipelines from Norway and continental Europe and tankers of LNG from countries including Qatar, Russia and the U.S.

Fracking, or hydraulically fracturing, involves extracting gas from rocks by breaking them up with water and chemicals at high pressure.

It is fiercely opposed by environmentalists who have raised concerns about potential groundwater contamination and say extracting more fossil fuel is at odds with Britain’s commitment to reduce greenhouse gas emissions.