Six firefighters were injured responding to a blazing car explosion in the Bronx Wednesday night, officials said.

First responders rushed to the blast around 7:06 p.m. at Westchester Ave. and Fox St. in Longwood, where stunned witnesses described the fiery mayhem.

“The fire started in the trash (outside an apartment building) and it spread under the car,” Frank Rojas, 26, an Amazon delivery driver who witnessed the eruption told the Daily News. “The car popped. There was at least two explosions.

“The first popping was from the trash and the second … explosion was the car,” he said. “The flames flew way up. It was a fireball.”

Three vehicles were damaged in the blaze — including a firetruck that was responding to the dangerous eruption, Rojas said.

The fire was placed under control around 8:19 p.m.

It was unclear what sparked the explosion; an investigation is underway, officials said.

EMS transported the injured firefighters to Jacobi Hospital for evaluation, the FDNY said.

Three of the injured firefighters were in stable condition, cops said.