Thillcraft harm other people. Some snowmobiles and jet skis can exceed 100 miles per hour, and lacking brakes, they are a safety risk to others using the public land and waters. Because of the speeds that are often driven by thrillcraft enthusiasts, other outdoor recreationists are sometimes run over, hit, or otherwise directly harmed by speeding thrillcraft.
There are the indirect environmental health effects. For instance, exposure to the air pollution in some heavily used thrillcraft has been shown to be a health hazard to workers and other non-motorized recreationalists.
But the real harm occurs to thrillcraft enthusiasts themselves. There were more than 550 documented deaths attributed to ORV use in 2006 with more than 146,000 emergency room visits were the result of accidents while on these machines. Some estimate that total death from ORV use is 800 people or more. A third of these deaths were children. The Oregonian estimated that the cost of these accidents is 3 billion a year. This drives up insurance rates for everyone.