Property owners of apartments and other multi-family rental units have until Dec. 31 to install carbon monoxide alarms in ccunits to comply with a 2010 state law. The Carbon Monoxide Poisoning Prevention Act required single-family homes with an attached garage or a fossil fuel source to install the alarms by July 1, 2011, but multi-unit property owners were given more time to come into compliance. Alarms are required in all units with attached garages or fossil fuel burning appliances.