Four Los Angeles firefighters were injured by an explosion while investigating a leak at a Silver Lake home.

Two firefighters remain hospitalized and two were released, Battalion Chief Nick Pellegrini told ABC7.com Wednesday afternoon.

Firefighters were called a little before 11 a.m. when an HVAC technician was unable to contain a Freon leak at the home on North Lakewood Avenue.

"When the engine company responded, we had one member in the basement trying to assist and an explosion occurred," Pellegrini said. "So we had a small explosion and the one member that was in the basement was slightly disorientated," Pellegrini said. "The other crew was still in the living area of the home and from there the crews left the structure at that point."

Branden Silverman, a captain with the Los Angeles Fire Department, told the television station that a flash fire occurred in the basement.

The firefighters were treated on scene and taken to the hospital.

"Injuries range from burns, concussion-type injuries from the explosions, and respiratory issues. We don't know the severity of the injuries," Pellegrini said.

The technician and residents of the home were uninjured, Pellegrini explained.

Arson investigators were called to the scene to determine what caused the explosion.