A significant number of workers each year in the U.S. are killed or sustain serious injuries in heavy machinery accidents. Those at highest risk are construction workers with heavy machinery such as diggers and cranes commonplace on building sites for earth moving and demolition. Other workers such as road maintenance and construction crews, or agricultural workers may also be at risk, as heavy machinery may be regularly used as part of their job. The most common injuries arising from a heavy machinery accident include crushed or amputated limbs, head and brain injuries, spinal injuries, burns and electrocutions. The majority of heavy machinery accidents may be caused by faulty equipment or operator error, while a significant number also occur when cleaning equipment without taking appropriate safety precautions. Certain pieces of heavy machinery are also associated with higher numbers of accidents than others, with cranes, backhoes, bulldozers and front-end loaders all posing a significant risk.