A popular baby seat is under fire by consumer advocates for its poor safety record. Four million Bumbo baby seats have been purchased in the U.S., according to the Detroit Free Press.

And apparently babies falling from the seat have been getting serious injuries, including 33 with skull fractures.

Made of stiff, colorful molded plastic, the Bumbo seat sits low to the ground and supports a baby's lower trunk, with round openings for legs. More in the nature of a toy than a traditional infant seat, the Bumbo does not have safety straps.

The federal Consumer Product Safety Commission issued a recall of the seat in 2007 because there was no warning label not to use the seat on a "raised surface" and those manufactured after that recall have included that warning.

A coalition of safety advocates want the CPSC to recall the seat again, this time because injuries continue even when the seat is used flat on the floor and not on raised surfaces. Young children are still getting injured falling to the floor from the chair, rather than from a higher perches.

If this second recall is issued, the advocates want the company to redesign the product and make it safer. The South African manufacturer has reportedly said safety straps would cause parents to have a "false sense of security" and that if the seat is "used as intended" it is safe.

Source: "Should Bumbo baby seat be recalled again?" Detroit Free Press, 2/10/12