A fire at a Belltown high-rise apartment building early Thursday left one man critically wounded. Investigators determined the fire was intentionally set.

The blaze started in the lobby of the building in the 2200 block of First Avenue around 2:40 a.m., according to the Seattle Fire Department.

While conducting their primary search of the fire ground, firefighters found and rescued an approximately 50-year-old man who had been in the lobby’s bathroom, according to fire department spokesperson David Cuerpo.

The man was taken to Harborview Medical Center in critical condition, Cuerpo said in an online statement. Two more people were treated at the scene for minor injuries related to the fire, but they did not require transportation to a hospital, he said.

Cuerpo said once it was determined that the fire was arson, the Seattle Police Department’s Arson Bomb Squad was notified.

The Arson Alarm Foundation is offering a $10,000 award to anyone with information that leads to the arrest or conviction of those responsible for setting recent fires in the vicinity, Cuerpo said.

Information about the fire can be shared by calling 800-552-7766 or emailing SFD_FIU@seattle.gov. You can choose to remain anonymous, the fire department said.

Cuerpo said several floors of the apartment building were evacuated because of unsafe smoke and carbon monoxide levels, and people were temporarily sheltered in a King County Metro bus. Firefighters used high-powered fans to ventilate the building and residents were able to return to their homes within a few hours.