The National Transportation Safety Board says a natural gas alarm belongs in your home, and it has the investigations to back that up. Natural gas is odorless on its own, so pipeline safety regulations require gas companies to add an odorant that smells like sulfur or rotten eggs, the NTSB notes. That smell does not always do the job.

The NTSB says some people cannot smell the odorant, are asleep, do not connect the smell with natural gas, or are not in the part of the building where gas is collecting. The odorant can also be stripped out when gas migrates through soil before entering a building, leaving it odorless again.

After investigating leaks that caused deaths, serious injuries and major property damage in homes and businesses, the NTSB says a natural gas alarm could have reduced the consequences of each through early detection and timely evacuation. The devices monitor the air and sound an alarm, much like a smoke detector, when they detect dangerous levels of gas. Unlike smoke alarms, the agency says, they are not required in homes or businesses, even those with gas service.

The NTSB recommends installing alarms that meet National Fire Protection Association 715 standards. They are sold online and at home improvement stores, the packaging gives guidance on placement, installation and maintenance, and a large building may need more than one. If an alarm sounds or you smell gas, the agency says to get everyone out of the building to a safe distance right away, then contact the gas company.