"Preliminary findings suggest that the fire was caused by an unsealed gas container inside a heater", Mr Gasiorowski said.
Karolina Barabas was identified as one of those who died.
Attorneys for the man charged said he was "deeply distraught" by the deaths.
Interior Minister Joachim Brudzinski said the girls were all 15-years-old. If convicted, he faces up to eight years in prison.
A police spokeswoman in the city of Koszalin, Monika Kosiec, said the victims were thought to have been celebrating one of their birthdays. Prosecutors said that carbon monoxide inhalation was the likely cause of the deaths.
A memorial for the victims.
The group was celebrating a birthday on Friday.
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Escape Rooms are a popular interactive adventure activity where participants must solve a series of puzzles and riddles in order to find the exit from a closed room.
Police and fire officials said they did not yet know what started the blaze in the escape room.
Poland's Prime Minister Mateusz Morawiecki vowed earlier on Sunday to close escape rooms that fail to meet safety standards after firefighters inspected almost 200 such facilities across Poland over the weekend.
Prime Minister Mateusz Morawiecki, along with Suski and Szymczyk, spoke after holding a meeting in which they discussed with other officials ways of improving safety at entertainment venues.
"The deepest sympathy for the families of all the victims of the great tragedy in Koszalin, where five young girls lost their lives".
According to Polish officials, they have shut down 13 escape room games due to safety flaws after the incident. Brudzinski ordered a Review of the compliance with the fire protection provisions in all of the more than a thousand Escape Rooms in Poland.