(NEXSTAR) — The U.S. Food and Drug Administration (FDA) is advising parents and caregivers not to use neck floats for babies after one child died and another was hospitalized.

The flotation devices — inflatable rings that are worn around a baby’s neck to allow them to float freely in the water — are marketed for children as young as 2 weeks old. In a news release Tuesday, the FDA warned against the use of the products, which can lead to “death or serious injury.”

“The FDA is aware that some manufacturers are claiming these products support water therapy interventions in babies with developmental delays or special needs and that the benefits of these products include increased muscle tone, greater flexibility and range of motion, increased lung capacity, better sleep quality, and increased brain and nervous system stimulation,” the release states. “The safety and effectiveness of neck floats to build strength, to promote motor development or as a physical therapy tool, have not been established.”

For children born with special needs requiring water therapy, such as spina bifida, spinal muscular atrophy type 1 or cerebral palsy, the devices can be especially dangerous because of the increased risk of neck strain and injury, according to the FDA.

The FDA says in the two documented cases involving death and hospitalization, the caregivers were not directly monitoring the children after they were placed in the neck floats.

While death or serious injury is rare, the FDA is warning that such events can and do occur. The FDA added that there may have been similar events that have gone unreported. Parents or caregivers are urged to report injuries or “adverse events” associated with neck floats via its MedWatch reporting program, along with details and descriptions of the products.