A 4th of July fireworks show turned into a fiery nightmare when a rogue firework exploded too close to a boat — setting off a chain reaction that turned the vessel into a floating fireball.

Check out the shocking video circulating social media … you can see the low-flying firework explode right over the boat on Alabama’s Lake Martin — setting off a devastating incident of pyro chaos.

The barge stayed afloat once the stunning bursts terminated, and emergency personnel rushed to the scene.

Sources connected to the incident tell TMZ at least 5 were hospitalized … with an unknown amount being taken by helicopter. No deaths have been recorded.

We’re told the fireworks show has been taking place on Lake Martin for years … and this was just an unfortunate accident.

The Tallapoosa County Sheriff’s Office referred TMZ to the Alabama Fire Marshall and Alabama Law Enforcement Agency Marine Patrol … who has not replied to our request for comment.

TMZ also reached out to the Tallapoosa County Emergency Management Agency and Stillwaters Volunteer Fire Department and Rescue, which reportedly responded — so far, no word back.