The Environment Agency has given fracking firm Cuadrilla permission to use a "nitrogen lift" during well testing at its Blackpool site.
The agency has approved changes to Cuadrilla’s environmental permit at Preston New Road, Little Plumpton.
The permit variation allows a process known as a nitrogen lift to take place for a limited number of days during the next phase of well testing operations.
This short-term activity during the exploratory phase uses nitrogen to assist with the removal of fluids in the well. This is a safe and commonly practiced technique in the oil and gas industry.
The decision follows rigorous technical assessment and modelling of the impact to the environment and people, and review of the comments submitted during a public consultation.
John Neville, Environment Manager for the Environment Agency in Cumbria and Lancashire, said: “After completing a thorough assessment of Cuadrilla’s application and fully considering all of the responses to our public consultation, we are confident that the environmental permit sets the right conditions to ensure that people and the environment are protected.
“The regulatory controls covered by the original permit provide a high level of protection for people and the environment. The changes we have agreed also meet these strict requirements so that the period of venting gas will be limited and the flaring of gas is controlled.
“Our inspectors will enforce the conditions of the permit to ensure that operations are carried out in line with the controls set out in the permit and the gas management plan.”
Fracking on site has been paused following a number of earth tremors earlier this year.
Cuadrilla has said it will return to the site in due course.
The firm's planning permission means that it cannot fracture or drill beyond November but it can remain a working site until 2023.
A "nitrogen lift" is the use of nitrogen gas circulated into the production conduit to displace liquids and reduce the hydrostatic pressure created by the fluid column.
Nitrogen lifting is a common technique used to initiate production on a well
A spokeswoman from the Preston New Road Action Group said: “As close residents of the PNR site we find it astounding that the Environment Agency have granted Cuadrilla permission to use a nitrogen lift.
“They will now be able to cold-vent climate-affecting methane and gases such as benzene that are harmful to human health, into the air that we are breathing.
"Nitrogen lift is a process usually used at the end of life of a well to extract the last bits of gas, yet Cuadrilla are going to be using it throughout the flow testing process.”
A new report from the National Audit Office has found that progress in establishing the shale gas industry in England has been slower than initially planned, while operators have said the system to protect against the risk of earthquakes is stricter than that used internationally and has hindered their development.
Meanwhile, opposition to the controversial extraction process is on the rise.