Have you ever put a new roof on your home? A little-known, but potentially deadly risk of carbon monoxide poisoning or fire can be created by roofers if exhaust vents are not checked immediately after the work is completed. Many homes are space-heated by forced air furnaces or have hot-water heaters that burn natural gas. The hot, poisonous fumes from the appliances are often vented outside through sheet-metal ducts routed through the attic roof. The roofer could unknowingly cause these vents to separate when working on the roof above. Often these pipes are just loosely connected, and as many as seven of 10 come apart when new roofs are installed. Yet many roofers don't check attics or vents when they're finished, and thus put homeowners at risk of deadly carbon monoxide poisoning or fire when hot gases are exhausted near a combustible material. And that is your On The House Tip for today.