largest firework shell every shot
WATCH: North America's largest firework detonated in Steamboat. The 48-inch shell was launched in February with 58 pounds of high explosives from a mortar buried 20 feet deep into a mountainside in Steamboat Springs. STEAMBOAT SPRINGS - In honor of the Fourth of July, check out the largest firework ever detonated in North America. At more than 1,175 pounds, it may be the heaviest ever set off in the world. The 48-inch shell was launched on February 6 as part of Steamboat's Winter Carnival.