Rescuers were struggling to locate three missing miners on Sunday after finding one crushed to death and locating another trapped after an earthquake hit a coal mine in the country's south, a mining official said.
Some 200 miners involved in the rescue were working in sweltering heat around a kilometre (0.6 miles) beneath the surface to find the three missing miners after one was found dead.
"A physician has pronounced him dead," Daniel Ozon, the CEO of the Jastrzebie Coal Company (JSW) managing the mine, told reporters on Sunday.
Ozon said the company believed the miner was 38 and had been working at JSW for ten years, but was waiting for the man's family to confirm his identity.
Ozon said that rescuers had "established visual contact" with another missing miner trapped between pipes, but it was unclear whether he was alive.
Rescuers have not been able to establish communication with any of three other missing men, Ozon said, adding that rescuers were building ventilation shafts to dispel high levels of methane hindering their efforts.
JSW is the largest company producing coking coal in the European Union.
Ozon said that family members of the missing miners were being offered psychological counselling at the mine site.
Two of the seven miners originally trapped after the quake, which struck Zofiowka in the Silesian coal basin on Saturday morning, managed to escape within hours with only minor injuries.
Poland's Prime Minister Mateusz Morawiecki visited the two rescued miners in hospital after meeting with mining officials late Saturday.
President Andrzej Duda arrived at the mine Sunday noon as the rescue operation was in full swing.
The earthquake hit the mine at 11:00 am (0900 GMT) on Saturday about 900 metres (3000 feet) below ground level, Anna Swiniarska-Tadla, a spokeswoman for the WUG mining office told PAP news agency.
Around 250 miners had been working underground when the quake struck, according to JWS.
Local residents also reported feeling a strong jolt in their homes in the region not known for seismic activity.
Coal is the main energy source in Poland with 65.5 million tonnes mined in predominantly state-owned mines the country last year.
Mining accidents have claimed over 200 lives in Poland over the last 45 years, according to statistics compiled by Poland's PAP news agency.
Poland's right-wing government and previous administrations have based their energy policy on plentiful domestic coal and taken little action to invest in or promote renewables to mitigate heavy pollution.
Smog from coal has spiked to record levels nationwide in recent years, with experts estimating there are some 50,000 premature pollution-related deaths per year in the country of 38 million people.
Poland is set to host the UN's COP 24 international conference on climate change late this year.
Family members and friends await news on the miners trapped down a coal mine in south Poland