 The NFPA standard is not necessarily enforced by law . As of April 2006 , the U.S. state of Massachusetts requires detectors to be present in all residences with potential CO sources , regardless of building age and whether they are owner @-@ occupied or rented . This is enforced by municipal inspectors , and was inspired by the death of 7 @-@ year @-@ old Nicole Garofalo in 2005 due to snow blocking a home heating vent . Other jurisdictions may have no requirement or only mandate detectors for new construction or at time of sale . 
