Peloton issued a voluntary recall of its two treadmills on Wednesday after coming under intense scrutiny from US regulators to do so. 

Regulators warned customers in April to stop using its $4,295 Tread+ treadmill, deeming it unsafe after it was reported that a child had died and others were injured while it was in use.

Peloton's CEO initially denied that its Tread+ running machine has any safety issues and said the company would not recall the product. A spokesperson reiterated this in an email to Insider in April: 

"A recall has never been warranted," the spokesperson said. "The Peloton Tread+ is safe when operated as directed and in accordance with the warnings and safety instructions."

On Wednesday, Peloton CEO John Foley  said that the company had "made a mistake" in its initial response and apologized. 

According the US Consumer Product Safety Commission, the independent federal agency that issued the warning about the treadmill, some of the machine's design features make it "particularly dangerous" to use. Specifically, the agency highlighted potential problems with the height of machine's base off the ground and well as the design of the running belt.

A spokesperson for CPSC previously told Insider that the agency was examining how the Tread+ differed from other treadmills on the market. 

"We have had injuries reported concerning other treadmills but to date, we are unaware of this hazard pattern involving other treadmills. For example, many injuries involve sudden acceleration of the treadmill, which is not the issue here," the spokesperson said. 

Thousands of accidents involving treadmills happen every year in the US. In 2019, there were 22,500 emergency-room visits related to treadmills, according to CPSC data reported by the Wall Street Journal. 

The CPSC shared a video alongside its warning about the Tread+ to demonstrate its safety concerns.

The footage showed two children playing, apparently unsupervised, on a Peloton Tread+. One of the children, who was playing with a ball at the rear of the machine, was sucked underneath while the treadmill's belt was moving. The child was eventually able to wriggle free. 

Regulators have highlighted the space between the ground and the machine's base as potentially posing a safety risk. The following photograph shows the size of the gap between the base of the machine and the floor, which is apparently enough space for a child to be pulled underneath, according to the footage released by the CPSC. 

Regulators were also examining the design of the running belt. While most running machines on the market have a flat and continuous running belt, the Tread+ belt is made up of 59 slats that are "mounted on a ball bearing rail system," according to Peloton.

The design is meant to make the running experience easier on the knees and legs as the slats are more shock-absorbent, according to Peloton.

Peloton customers have been debating the safety of the Tread+ in private Facebook members' groups online in recent days. Some users suggested that the lack of a "safety bar" at the rear of the machine could be the issue.

Richard Moon, director of fitness consultancy agency Motive8, which designs and installs gyms and fitness centers, and an expert in the sector, told Insider that "safety bars" are not standard on all machines. Motive8 does not currently work with Peloton. 

Moon said that he felt the best way to prevent accidents from happening would be to have a safety feature in the software that forces the machine to cut out if it feels a resistance to the point that it stops the belt from running. This could, therefore, help to prevent objects from being dragged underneath. 

Peloton's CEO John Foley previously said in a letter to Tread+ members that the company would update the software to add an access code to the machine to prevent it from being used when the safety key hasn't been removed.

William Wallace, safety policy manager for Consumer Reports, said that the recall is "the right move for consumers."

"As a safety advocate and close observer of the CPSC, I can say: it's highly likely Peloton changed course because the CPSC stood its ground on behalf of consumers. The agency made a clear and compelling case for why the Tread+ puts people at risk, and people seemed to recognize that Peloton wasn't doing all it could to keep people safe and make its customers whole.

"We're very glad to see Peloton come to its senses, apologize for its mistakes, and offer a full refund," he wrote in an email to Insider on Wednesday.