The law applies to all single-family homes with an attached garage. It also applies to homes containing fuel burning appliances such as a grill or generator. Owners are required to have a carbon monoxide alarm on each level of the house.
The law first took effect in January for construction of new homes. Starting Friday, it applies to existing homes as well. The alarms sell for less than $50 dollars at home supply stores.
Carbon monoxide is an odorless, colorless and deadly gas. About 400 people die each year in the U.S. from carbon monoxide poisoning.