South Africa has lifted a moratorium on shale gas exploration in the semi-arid Karoo region, imposed 17 months ago pending further study on the use of hydraulic fracturing.

Collins Chabane, a minister in the President’s office, said the country’s cabinet had decided to lift a moratorium after a study eased safety concerns related to the extraction technique.

“When (the results of the study) … came back, they recommended that it was clearly safe for us to have that programme of exploration of shale gas,” Chabane said, according to Reuters.

The US Energy Information Administration estimates South Africa may hold 485 trillion cubic feet of technically recoverable shale gas resources, or the fifth most of 32 countries studied worldwide, most of it in the Karoo Basin.

Shell, Falcon Oil & Gas, Sunset Energy and Anglo-American are among the explorers who stand to benefit from the lifting of the ban.

Shell said last year it hoped to invest $200 million to explore for shale gas in the Karoo, while Johannesburg-listed Sasol Petroleum in November put its shale gas exploration plans on hold pending news on the ban.

Ferrial Adam, a climate and energy campaigner at Greenpeace Africa, said the decision could start a process that could have a devastating impact for the region.

“At the end of the day it is still fracking. They are going to use a lot of water with a enormous amounts of chemicals in them in an area that is water scarce,” she said.

Jonathan Deal, chairman of the Treasure the Karoo Action Group, said the decision was “hasty” and “ill-informed”, and vowed to mount legal challenges against exploration licences issued in the wake of the lifting of the moratorium.