Nine firefighters were injured Feb. 15 in an explosion while responding to a fire involving a truck with pressurized cylinders.

Los Angeles Fire Department (LAFD) firefighters responded to a fire located on North Alameda Street in Wilmington, in the Harbor region of Los Angeles, shortly before 7 a.m. when the truck exploded.

The truck’s driver was not injured, according to fire department officials.

The firefighters were transported to a local hospital, with at least two initially in critical condition, according to officials.

LAFD Chief Kristin Crowley said one of those firefighters’ status is now “stable,” but he may stay at Harbor UCLA Medical Center for additional observation.

“He was awake and alert and talking,” Ms. Crowley said.

The second critically injured firefighter had to be intubated and was transferred to Los Angeles General Medical Center for treatment at a burn unit, she said.

Dr. Molly Deane of Harbor UCLA Medical Center said the other firefighters suffered various levels of burn and blast injuries.

After seeing video of the explosion, she said, “frankly it’s remarkable none of them were more severely injured.”

According to reports from the scene, the explosion occurred in a tank of compressed natural gas that was part of the truck’s fuel system.

The circumstances of the blast were under investigation, and drivers were advised to avoid the area.

City News Service contributed to this report.