That is because they are explosives dumbass. Also they are loving awesome, and you can buy ear plugs. Its awesome here because they are legal to shoot until midnight from the 1st to the 4th. Almost everything is legal, I had a 360 degree fireworks show from my balcony tonight.
My favorite thing to do is buy those little cardboard firework tanks, and sometimes I set them up to shoot each other. Then I blow them both up with firecrackers and ground blooms.