Four police officers injured while evacuating two houses during a major fire Wednesday all have been discharged from the hospital.

Officers John Carrano, Carlos Pabon, John Topolski and Matthew Goncalves all were treated for smoke inhalation after they arrived at 181 Poplar St.  and worked to evacuate residents from that house and one next door.

“They went above and beyond,”  said police Capt. Robert Gearing, who checked Wednesday night on the officers. The officers were in the area and arrived before the fire department to find the house ablaze. “This is one of the more dangerous situations for a police officer.”

The cause of the blaze, which caused very extensive damage, remains under investigation but police said it is being treated as an arson investigation. The detective bureau and Fire Marshal’s office are collaborating on the investigation.

The fire was a difficult and dangerous one to battle for firefighters. When firefighters arrived, the first and second floors were already fully involved in fire but initial accounts said several children might still be inside. As firefighters began the battle, others conducted a primary and secondary search inside the burning building for possible victims. They found none. The children had already escaped the house. Then additional information was received that a teenager might be in the home. Chief Ivan Fossesigurani ordered a third search. The teen also had escaped.

“It was very difficult conditions. The firefighters took a hell of a physical beating,” Fossesigurani said. “The guys did a great job pushing back the fire from the rear and also protecting the house next door. Heck of a job.”

The American Red Cross was called in to assist displaced residents.