The U.S. Food and Drug Administration is urging parents and caregivers not to use baby neck floats after the death of at least one infant and hospitalization of another. In both cases, the babies were injured while not being directly monitored, the agency cautioned on Tuesday.

The inflatable plastic rings can be worn around a baby’s neck, letting the infant float freely in water. Some are marketed for those as young as two weeks old, as well as premature babies or those with developmental delays or disabilities. 

While the necks floats are touted by manufacturers as a product that gives babies mobility and as a valuable tool for special-needs infants and kids, the FDA said the effectiveness of the products has not been established.

The agency recently became aware of companies marketing neck floats for use as a water therapy tool without FDA clearance or approval, it stated. 

“The safety and effectiveness of neck floats to build strength, to promote motor development or as a physical therapy tool, have not been established,” the agency stated. “The risks of using neck floats include death due to drowning and suffocation, strain and injury to a baby’s neck. Babies with special needs such as spina bifida or SMA Type 1 may be at increased risk for serious injury.”

Baby neck floats started gaining in popularity a number of years ago, with photos of the pint-sized swim devices cropping up on social media and prompting one pediatrician to describe the products as “potential death traps” in multiple news accounts.