According to ABC affiliate WSOC-TV, fireworks triggered "small explosions" inside a mailbox and a trashcan northeast of Charlotte on Wednesday.
Near South Rowan High School, a man told WSOC he heard a "loud boom" and went outside. He saw smoke coming from his sister's mailbox, right next to his. When the man opened his mailbox, he found an unlit firework.
Captain Mark McDaniel from the Rowan County Sheriff's Office told WSOC that at the same time this report was received, another 'loud boom' was reported about a mile away. China Grove police discovered "a device detonated" there in a trashcan.
There are no reported injuries.
A spokesperson for the sheriff's office told WSOC that the discovered fireworks were "similar to a mortar shell you light and put in a tube to launch."
Most fireworks are illegal in North Carolina, but some types are permitted, including sparklers, glow worms or snakes, smoke bombs and noisemakers. If it flies in the air and explodes, it is illegal.