PLANO, Texas (CBSDFW.COM) – A 6-inch mortar exploded inside its launching tube, resulting in a chain reaction of other nearby mortars exploding as well, sparking fires and ending Plano’s Fourth of July fireworks show prior to the grand finale.

Plano Fire-Rescue said it responded to the fires Saturday night near Spring Creek Parkway and Jupiter Road related to the city’s fireworks show.

Crews worked through the evening to contain one of the fires at Lavon Farms. At around 11 p.m., officials said this fire was “100% contained.”

Officials said the other fire was in the Oak Point Nature Preserve, but it was extinguished about 30 minutes after it was reported.

Video from the incident shows fireworks going off near ground level and sparking fires on nearby grassy areas.

No injuries or damage to structures were reported, however the fire resulted in several acres of burned field.

It took firefighters one hour to contain and completely extinguish the hot spots.

The Fire Marshal’s Office and pyrotechnic company will remain onsite overnight as they determine the safest way to remove the unexploded fireworks.