Carbon monoxide detectors are hot items

At the venerable Charles Street Supply Company, Beacon Hill's go-to hardware source since 1948, the usual hammers, nails, and screwdrivers that fly out the door have been supplanted by a new best-seller: the carbon monoxide alarm.

''We can't keep them in stock," said owner Jack Gurnon. ''We ran out about two days ago."

He quickly added that the store, now part of the ACE Hardware chain, will have a new supply in stock today, just a day before a state law goes into effect requiring carbon monoxide alarms to be installed in all homes with garages, or with wood- or fossil fuel-burning equipment, such as oil, gas, and coal stoves and burners.

Governor Mitt Romney signed the law in November, setting a March 31 deadline for installing the devices. The death in January 2005 of 7-year-old Nicole Garofalo, who perished after her Plymouth home filled with carbon monoxide gas, prompted the measure and led to its nickname, Nicole's Law.

In the last three months, people in Cambridge, Brookline, and Bellingham have been hospitalized after suspected incidents of carbon monoxide poisoning.

''Carbon monoxide is invisible. You can't see it, smell it, or taste it. The symptoms of CO poisoning are flu-like, and what do we do when we have the flu? Take an aspirin and a nap," said state Fire Marshal Stephen D. Coan. ''But when you have CO poisoning and not the flu, that is the exact opposite of what you should do. You need to get outside into fresh air or you might never wake up. Carbon monoxide alarms will give you the early detection and warning you need."

State officials have said they understand that widespread compliance to the new law will take time. The law will be enforced mostly during home sales. Under it, homes that are on the market must pass inspection by local fire departments, who will check for carbon monoxide alarms in addition to traditional safety criteria.

With tomorrow's deadline, hardware stores large and small have been inundated with shoppers seeking the latest in carbon monoxide detection technology.

At the Home Depot in Mansfield, employees put together a rack of the devices and displayed it at the front of the store.

''It's the item that everyone's coming in to look for," said store manager Mike Joughin. ''We're just trying to keep the product in front of them."

Prices range from $21.97 to $48.96, he said.

Home Depot's massive supply chain has been able to send its Massachusetts stores a steady supply of products, according to Joughin, but Gurnon said that local ACE Hardware-affiliated stores, supplied by a warehouse in New York state, recently ran out, though the chain has scrambled to resupply its Bay State stores by today. ''Every other phone call we get these days is about carbon monoxide detectors," said Gurnon.