A child was killed in an accident involving the Peloton’s Tread Plus treadmill, Peloton CEO John Foley said in a note posted to the company website Thursday.

“I’m reaching out to you today because I recently learned about a tragic accident involving a child and the Tread+, resulting in, unthinkably, a death,” Foley wrote. “While we are aware of only a small handful of incidents involving the Tread+ where children have been hurt, each one is devastating to all of us at Peloton, and our hearts go out to the families involved.”

Peloton declined to provide further details about the child, the incident, or the “handful of previous incidents” Foley referenced. The company said in a statement that everyone at the company was saddened by the news.

The company’s statement adds that the Tread Plus was designed and tested for use by people over 16 and weighing more than 105 pounds. “Additionally, when the Tread+ is not in use Members should continue to follow the safety instructions by storing the safety key, which keeps the Tread+ from operating, away from the Tread+ and out of reach of children,” it says.

Foley warned that children and pets should be kept “away from Peloton exercise equipment at all times. Before you begin a workout, double check to make sure that the space around your Peloton exercise equipment is clear.” He also said the company is “currently assessing ways to reinforce our warnings about these critical safety precautions to hopefully prevent future accidents.”

Despite their somewhat expensive price tags, Peloton’s stationary bikes and treadmills have been hugely popular during the coronavirus pandemic, with most gyms closed and people social distancing at home. The company reported that its revenue increased 66 percent year over year in the first three months of 2020. The company struggled to keep up with the demand for its products early on, however.

In October, Peloton issued a recall for clip-in pedals on about 27,000 of its bikes following reports of broken pedals that caused injuries, including several that required medical care.

Some 25,000 children are injured annually in home exercise-related equipment accidents. One of the most common types of injury is friction burns that happen when a child touches a moving belt on a machine. In 2009, boxer Mike Tyson’s four-year-old daughter, Exodus, was killed in a treadmill accident after a cord wrapped around her neck.