The new carbon monoxide (CO) alarm law requires that "every single-family dwelling and every dwelling unit in a multifamily dwelling" have "an approved and operational carbon monoxide alarm installed within ten feet of each room lawfully used for sleeping purposes." (See MN Stat. 299.51) This law was effective as of August 1, 2007 for newly constructed homes, and just became effective August 1, 2008 for all existing single-family dwelling units. It becomes effective in August 1, 2009 for existing multifamily dwelling units. The alarms must be an approved device (conforming to UL2034 standards), and may be hardwired, plugged in, or battery-powered (if attached to the wall).
So, yes, this means YOU, all home owners in Minnesota, must have CO detectors or you are breaking the law! But some how I doubt most of you will be running out and picking one up. Just know that when you go to sell, you should make sure to have one within 10 feet of all bedrooms. Failure to comply with the law could hurt your wallet in the future...with the sue happy society we live in, a buyer that is later injured by Carbon Monoxide poisoning could come back and take you to court for damages.