A lithium-ion battery is to blame for an early morning fire in Brooklyn.

Construction crews were busy boarding up the windows of Prompt Cleaners on Avenue M in Midwood Thursday.

Fire officials said the business, and two apartments on the second floor sustained severe damage.

“Heavy fire amange throughout. They had fire from front to rear and pretty much ruined,” Deputy Assistant Fire Chief Brian Gorman said.

According to the FDNY, firefighters responded to the blaze minutes after receiving a call around 6:30 a.m.

Officials said the fire then started to grow.

“Units responded within three minutes and 23 seconds. It quickly escalated to a second alarm. We had four victims,” Gorman said.

Authorities said one of the victims was critically injured after suffering from respiratory distress and burns. The other three sustained minor injuries.

Meanwhile, a charred e-bike could be seen getting pulled from the two-story building.

“We did recover a micro-mobility device at the base of the stairs, which is the area of origin which is powered by a lithium-ion battery,” Chief Fire Marshall Daniel Flynn said.

“It was in the hallway which lead to the problem with the victims being evacuated,” Gorman added.

According to the FDNY, there have been 107 lithium-ion battery fire investigations so far this year, not including the most recent one in Midwood. Officials said 46 people have been injured, and one person has died.

The Red Cross is providing financial assistance and emergency lodging to several people displaced by the fire, including three adults and one child.