DENVER (KDVR) — Two homes were destroyed in an overnight fire that injured one of the firefighters on the scene.

South Metro Fire Rescue said the fire was burning two homes on Kimball Street in Parker at 12:23 a.m. Tuesday. Two minutes later, they tweeted that a second alarm had been transmitted.

A couple of hours later, they said one firefighter was transported to the hospital with “a minor burn injury.”

The investigators determined that the fire was caused by “improper disposal of legal fireworks” in a plastic bin outside of the garage.

According to South Metro Fire Rescue, both homes were destroyed and families were displaced.