 Rocky Mountain News Network, I'm Kristen Thober. With 4th of July right around the corner, it's important to know that any firework that explodes or leaves the ground is illegal in Colorado, with exemptions made only on a permitted basis to those with proper certifications. Some laws around fireworks vary by city or county. For instance, Aurora Fire Rescue has temporarily lifted a fire restriction through the 4th. If you see illegal fireworks, you can call local