Returning to homes and businesses after a disaster can pose significant health and environmental challenges, like leaking natural gas lines, carbon monoxide poisoning, and asbestos exposure. First, be sure your local authorties have cleared your area for re-entry. Before you begin cleaning, seek advice from public health authorities and help from specialty contractors. Although these services may be difficult to contact after an emergency, EPA strongly advises against attempting to remove potentially contaminated material yourself. Exercise caution when disturbing building materials to prevent physical injury or other health effects. Building materials may contain hazardous substances such as asbestos that when carried by the air can be breathed in and cause adverse health effects. If you are unsure whether something contains asbestos or another hazardous substance, treat it as if it does. Do not attempt to remove it yourself; wait until a professional can do it for you.