Might not provide adequate head protection in fall.

Products: 4,500 bicycle helmets sold 10/05 through 5/06 at authorized Trek dealers nationwide for about $130. Hazard exists because the helmets failed to meet the Consumer Product Safety Commission standard for impact resistance. Consumer Reports tested both helmets and judged them "Not Acceptable," after which we contacted the manufacturer and CPSC. The recall was announced shortly thereafter. The helmets can be identified by the attached label, which says "Trek Anthem C." Men's sizes came in black and charcoal color, blue and silver, and blue and red. Women's came in aqua blue and silver, and white and silver. Recall encompasses helmets of any adult size.

What to do: Stop using helmet and return it to dealer for refund. For information, call Trek Bicycle at 800-373-4594.