The incident occurred around 6:15 a.m. in the Cheongna district of the port city, according to the Incheon Fire Department.
Closed-circuit television footage showed a white car emitting smoke before exploding into flames, which spread to other cars parked in the garage. Police said the vehicle was identified as a Mercedes-Benz EV.
Twenty residents, including seven children under 10, were hospitalized for smoke inhalation, and one firefighter was treated for dizziness.
Immediately after the blaze started, black smoke spread throughout the apartment building, prompting the evacuation of 103 residents, while 106 others were rescued via staircases and balconies. About 70 vehicles sustained damage.
The blaze was fully extinguished at 2:35 p.m. after an eight-hour battle. Authorities deployed 177 firefighters and 80 pieces of equipment, including ventilation vehicles.
The affected apartment complex consists of 14 buildings housing a total of 1,581 households. Police and the fire department are investigating the exact cause of the fire and the extent of the damage.