Peloton is warning owners to keep their children away from their treadmills after an accident involving its Tread+ in which a child died.CEO John Foley sent a letter to Tread+ owners Thursday, saying the warning comes after a "tragic accident involving a child and the Tread+, resulting in, unthinkably, a death."He didn't reveal details of the fatal accident, but he did note Peloton is "aware of only a small handful of incidents involving the Tread+ where children have been hurt."Overall, exercise equipment as a category can be particularly dangerous for children: 25,000 kids under the age of 10 are injured by exercise equipment each year, according to a 2014 study from the U.S. National Institutes of Health. In 2019, the Consumer Product Safety Commission estimates U.S. emergency departments treated 2,000 treadmill-related injuries in children under 8.Peloton said in a statement to CNN Business that there are "no words to express the shock and sadness everyone at Peloton feels as a result of this terrible tragedy." The company won't be disclosing any additional information about the incident "out of respect for the family and privacy."Recommendations to help kids stay safe"We design and build all of our products with safety in mind," Foley wrote. "But in order to help ensure that you and your family members stay safe with Peloton products in your home, we need your help."Foley said Peloton recommends its customers keep children and pets away from equipment at all times. Before a workout, they should ensure the area is completely clear — and once they're done, they should remove the treadmill's safety key (required to be inserted for the machine to work) and store it out of reach.NIH similarly recommends positioning treadmills to face the doorway, or using a mirror to improve visibility, if children are present in the household.People of all ages are more likely to injure themselves on treadmills than any other kind of exercise equipment, the NIH study found. Americans report 46,000 treadmill-related injuries each year — more than four times the number of stationary bike accidents, the next-most dangerous kind of exercise equipment.Treadmills comprise two-thirds of exercise equipment injuries, even though they represent just a quarter of exercise machines, NIH said. The group did not break out how many children are injured specifically by treadmills.Peloton's Tread+, which costs $4,295, features carbon steel and aluminum as well as a motorized belt for walking or running. The company recently revealed a lower-priced treadmill for $2,495 that's expected to ship in late May. Both have large screens to stream Peloton classes.