Apparently the hardware on the drop side bar can fail, causing it to separate and make a space where a child can slip and become strangled. One child did recently die in Iowa as a result of his injuries.
Several makes and models are affected. Please review this release by the Consumer Products Safety Commission and if you find yours is listed, stop using it immediately and contact the company at 866-762-2304 between 7:30 and 4:00 EST. You may also visit their website at Dorel-Asia.