WARSAW, Poland (AP) — New blasts at a Polish coal mine injured 10 rescue workers and forced authorities on Friday to suspend the search for seven coal miners and rescuers still missing after deadly methane explosions earlier this week, officials said.

The initial explosion took place shortly after midnight early Wednesday and was followed by another one hours later, about 1,000 meters (3,000 feet) underground at the Pniowek mine in Pawlowice, near the Czech border. Authorities said the two blasts killed five workers, left seven missing and injured dozens.

On Thursday night, new explosions injured 10 rescue workers who were trying to create safe conditions for the search for the seven missing men. Authorities then decided to pull all rescue teams out and seal off the area of the repeated blasts at the mine, where the missing are believed to be, with a dam.

Tomasz Cudny, the head of the mine operated by the JSW company, said it was a “very difficult decision” to halt the search but it was taken out of concern for the well-being of rescue workers.

“It would be very risky and very irresponsible to send them to such a dangerous area,” Cudny said.

Seven people were hospitalized after Thursday’s blasts, three of them in serious condition.

A dam is to be built within days to temporarily seal off the zone of the blasts from the rest of the mine for safety reasons, but also to help improve the atmosphere and the security conditions in that zone, a spokesman for JSW, Slawomir Starzynski, told The Associated Press.

On Thursday, JSW said 25 people injured in the original explosions remained hospitalized, nine of them in very serious condition at a hospital that specializes in treating mine accident victims, especially those with severe burns.

The deaths and injuries make it the worst incident in the history of the coking coal mine, which was built in the 1960s.

Before the search for missing miners was suspended, JSW had said rescue crews were pumping air underground seeking to lower the methane levels and reduce the risk of further blasts.

Poland relies on its own coal and coal imports for almost 70% of its energy needs, drawing criticism from the European Union and environmental groups concerned about CO2 emissions and climate change. Most Polish coal mines are in the southern Silesia region.

The Polish government has been scaling down the use of coal and recently announced it would end coal imports from Russia by May, part of Poland’s drive to reduce its dependence on Russian energy in response to Moscow’s invasion of Ukraine.

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