HealthDay News reports that U.S. children continue to suffer severe injuries from both regular power lawn mowers and ride-on mowers, as found in a new Pennsylvania-based study. In more than half of such cases studied, children required an amputation.

“The vast majority of the injuries could have been prevented if safety guidelines had been followed,” researchers said.

Those guidelines, outlined in 2001 by the American Academy of Pediatrics (AAP), recommend that no child under the age of 16 should operate a ride-on mower, while no child under 12 should operate a powered or non-powered push mower.

The advisory further cautions parents — whether on farmland or in the suburbs — to keep all children under the age of 6 indoors when any mower is in operation. Kids shouldn’t ride along as passengers on mowers operated by adults, the pediatric group said.