Chiacchia, a bronze medalist at the Athens Summer Games, suffered catastrophic injuries in March when his horse fell over a fence, nearly crushing him.

Recently, 12 riders worldwide died in falls in the eventing discipline, which enthusiasts consider the "ultimate test of horse and rider," The New York Times said Wednesday.

A cross-country phase of the event requires participants to clear more than 20 jumps and all of the recent deaths occurred during this phase.

Organizers encourage competitors to review the course and raise any complaints to officials, but Mark Phillips, the U.S. Olympic eventing coach, said riders issued no complaints at the event where Chiacchia fell.

Five British riders died during a short period in 1999, prompting officials to design pins that release fence rails when a horse hits it, but, with a cost of $70 per fence, only 4 percent of British courses use them and there are even fewer in the United States.

Chiacchia sits as the chair of a task force addressing safety concerns and the group plans to issue its recommendations to the U.S. Equestrian Federation later this month.