Graco is recalling thousands of its high chairs. The recall involves about 86,000 Graco classic wood high chairs in the United States and about 3,400 in Canada. The high chair's seat can become loose or even detach from the base, posing a fall hazard to the child. Graco knows of nine incidents in which children fell as the seat became detached, resulting in bumps, bruises and scratches and one report of a concussion in Canada. Consumers should stop using the chairs and contact Graco for a free repair kit at 800-345-4109 or at www.gracobaby.com .