LANSING (AP): New Michigan homes will have to come with carbon monoxide detectors starting March 23, 2009.

Gov. Jennifer Granholm signed the measure into law in December, but held a ceremonial signing Thursday to mark the law taking effect.

The change was prompted by the 2003 deaths of Patty and Gene Overbeck.

The elderly couple died from carbon monoxide poisoning in their retirement home overlooking Elk Lake in Antrim County after Patty Overbeck accidentally left a car running in the garage.

Carbon monoxide is a colorless, odorless gas, and the Overbecks were overcome before they realized they were in danger.

Democratic state Rep. Gary McDowell of Rudyard sponsored the bill.

Detectors cost $30 to $50. First Alert has donated 500 to be distributed to low-income families.