Fluorescent and some high intensity discharge (HID) lamps contain mercury, a hazardous substance regulated by Federal and State laws. Lamps that contain mercury will be marked with a circled "Hg" and “Contains Mercury”. These lamps must be recycled or disposed in accordance with local, state or federal law. For more information visit www.lamprecycle.com. If you are not the end user of these lamps you may be required by law to inform the purchaser that these lamps contain mercury and must be properly disposed or recycled. Check your State and Local laws for compliance.