According to Wikipedia:
“Carbon monoxide poisoning occurs after enough inhalation of carbon monoxide (CO). Carbon monoxide is a toxic gas, but, being colorless, odorless, tasteless, and initially non-irritating, it is very difficult for people to detect. Carbon monoxide is a product of incomplete combustion of organic matter due to insufficient oxygen supply to enable complete oxidation to carbon dioxide (CO2).
It is often produced in domestic or industrial settings by motor vehicles that run on gasoline, diesel, propane, methane, or other carbon-based fuels and tools, heaters, and cooking equipment that are powered by carbon-based fuels. Exposures at 100 ppm or greater can be dangerous to human health.”
In the average American home there are several sources that can cause carbon monoxide to be released. Any of these sources has the potential to become dangerous or even fatal.
Another factor not mentioned by Wikipedia is that CO is a very sticky gas and by nature does not dissipate quickly or easily. If a home becomes saturated with this odorless gas it will cling to the walls, closets, draperies and any little nooks and crannies that it can. It takes extensive airing out to clear a house safely from carbon monoxide.
Building codes, and industry safety standards keep our homes safe as long as we follow the procedures. Carbon monoxide detectors can also be an important tool for keeping our families safe while at home.
CO is given off as a waste product by any kind of combustion. Gas water heaters and furnaces are probably the most common sources of CO in the home. When water heaters are not vented properly, or have leaks in the vent pipes they can pump CO into the home air space.
A condition known as negative air pressure can also suck CO fumes out of even a properly vented furnace or water heater and into the living area. Large attic fans or other ventilation systems can create enough negative pressure (going in the wrong direction) to overcome the normally sufficient venting process of a gas appliance and pull CO into the home. Gas dryers are also subject to the same issues.
Other sources for carbon monoxide poisoning in the home are vehicles left running in the attached or built in garage, generators, and even barbecue grills.
The source of CO gas does not have to be inside the home to cause a serious problem. Last year my sons school had contractors working on the roof and running generators for their power equipment. The generator was too close to a fresh air intake on the roof and caused quite a problem before school officials were able to figure things out.
A trained and experienced Home Inspector can detect conditions in appliance vents, generators, furnaces and garages that may lead to CO poisoning.
One way to think of home inspections is that they are a safety inspection for your home and family. Industries are subject to safety standards and conduct safety inspections. Your family is more important than an industry!