Jeremy Paniagua's mother died saving his life after a fire broke out in their two-bedroom apartment in East Harlem in February 2005. His mother, Jeanette Montanez, threw her 11-year-old son into a bathtub and covered him with her body to protect him from the flames. Her silhouette was burned onto the flesh of his back by the intense heat and flames.

"His back is burned pretty badly, but you can see the patch where she held him, where she put her head between his shoulder blades and where she held onto his right arm," says Mallory Claudio, Jeremy's older sister, who was pulled out of the 112th Street apartment by firefighters.

Investigators later determined the fire that killed Montanez was started by a cigarette. And while there was a working smoke detector in the apartment, it may have failed to give the kind of advanced warning that allows people to flee fires with their lives, and without scarring burns.

Two types of protection

Approximately 96 percent of American households have at least one smoke alarm, the vast majority of which are traditional ionization smoke detectors. These use tiny amounts of radioactive material to detect fine smoke particles, the type generated by hot fires with high flames most commonly started by cooking accidents or improperly tended candles.

But a growing number of experts are lobbying for a shift toward photoelectric smoke detectors, which are faster at detecting the larger smoke particles that are generated by smoldering fires, like those caused by smoking accidents or slow-developing electrical fires. Photoelectric sensors shoot beams of light into a chamber that are not aimed at a sensor, but deflected toward the sensor by smoke particles.

In May of 2012, five New York City Councilmembers proposed a law to require photoelectric smoke detectors in residential buildings. Councilwoman Elizabeth Crowley, who chairs the Fire and Public Safety Committee, was the prime sponsor of the proposal.

"We know that the photoelectrics are better at alerting people to the fires that are killing more people," says Crowley. "A lot of people die from smoke inhalation and not raging fires. The traditional smoke alarms go off frequently when people are cooking or showering and they disable them and forget to reconnect them."

Although fires caused by smoking accounted for only 5 percent of structure fires in the United States between 2006 and 2010, they were responsible for the highest percentage of fatalities (24 percent), followed by fires involving heating equipment (20 percent) and cooking equipment (15 percent). According to some researchers many of the smoking-related deaths could have been prevented if the structures they occurred in had been required to have the slightly more expensive photoelectric smoke detectors, which most building codes do not now require.

Marshal's crusade

The fire that killed Montanez occurred in the New York City Housing Authority's Johnson Houses development. Claudio, who was 18 at the time of the blaze, later found out that the New York City Housing Authority, like nearly all landlords, used the less expensive ionization smoke detectors. (NYCHA declined to comment, citing the pending legislation.)

Claudio learned that the fire she survived involved an ionization smoke detector through the dogged persistence of a man named Jay Fleming. A deputy fire chief from Boston, Fleming's obsession with photoelectric smoke detectors began after a 1990 fire—started by a cigarette—killed five members of a Boston family, including three children ages 3, 2 and 10 months.

Fleming, who has a master's degree in engineering, researched the issue and began applying pressure to push for legislative change. He routinely reaches out to survivors and relatives of fire victims and tries to enlist their aid to pressure municipalities to change their laws and building codes.

"There are tons of studies that conclude that an ionization smoke detector will not give you enough time to get out of the house in a smoldering fire," says Fleming, who managed to get the Massachusetts state legislature to require photoelectric detectors in his home state. "I believe that somewhere between 10,000 and 15,000 people have died unnecessarily over the past 20 years because they didn't have adequate information about their smoke detectors."

Fleming says he only uses photoelectric detectors in his home because hot, fast moving fires—the ones that ionization detectors are best able to detect—frequently occur from cooking accidents while people are awake and able to either put the fire out or get out of the building. He's more worried about smoldering fires, which begin quietly and can disable or kill with subtle smoke, and which ionization detectors are slower to detect.

Claudio says that the night her mother died, she was awakened by the ionization detector, but by the time she woke up, the two-bedroom apartment was so filled with smoke she could barely see or breathe. "All I saw was thick black smoke and some sparks," she says. "I ran to the window by the air conditioner and just stayed there, it was the only place there was any air. That's where the firemen found me and took me out."

Codes don't differentiate

The city's building code specifies where smoke detectors must be located and how they are to be connected to one another and to fire dispatch systems, but is silent on what type of detector to use. Same with the separate New York City Fire Code.

The New York City Fire Department, the National Fire Protection Association (NFPA) and several other agencies recommend installing both types of smoke detectors, but have only begun making the recommendation within the past few years and have stopped short of pushing for requiring photoelectric devices.

Fleming maintains that most of the time the smoke detector industry sponsors free smoke alarm giveaways, they donate ionization models. Heather Caldwell, a spokeswoman for Kidde, the world's largest manufacturer of fire safety products, would not provide specific numbers about her company's donation policy.

"I don't think it really matters what the larger share of the donations are," Caldwell says. "If you talk with fire departments they would say that if they're getting a donation of smoke alarms it's important to them to get as many smoke alarms as they can so they can protect as many houses as they can." She says the company does donate dual technology and photoelectric units where local codes require them, and emphasized that all the company's products have to pass standardized tests.

"Each technology has its strength, and each responds differently to different types of fire," says Christian Dubay, vice president and chief engineer for the NFPA. "The problem is you don't know what kind of fire you're going to have."

Dubay is familiar with the criticism leveled by those who believe photoelectric technology is superior. Professor B. Don Russell of Texas A&M University has gone on national television recently showing tests he has conducted where photoelectric detectors outperform ionization in smoldering fires.

"You can set up scenarios. You can set up demonstrations that push the limits of both technologies. You can create conditions that will either further the capabilities of each technology or take away from them," says Dubay. The NFPA's latest fact sheet on smoke detectors warns the public that televised tests can be misleading.

Dubay says the data he has studied supports the conclusion that the ideal safety scenario involves installing both technologies, either as separate units or as a combination unit. The average price for a battery-operated ionization smoke detector is about $15. Photoelectrics cost about $25 and dual technology devices run around $40.

One of Fleming's critiques of the entire fire safety community is that people have known since at least 1980 that photoelectric units are better at detecting the types of fires that kill the most people, and that organizations like the NFPA have only begun advising people to use both technologies in the past few years. Dubay responded to that criticism by saying his organization relies on data from a multitude of sources and that upgrading fire safety recommendations is a complex and ongoing process.

"UL (Underwriters Laboratories) is actually getting ready to establish a new list of criteria in response to the way furniture and carpeting and interior furnishings are changing in their construction types," he says. "The smoke is actually changing, the qualities of the smoke. So we have to make sure that the smoke detectors, both photoelectric and ionization, are responding adequately to the new smoke and the old smoke."

False alarms, real risks

Smoke alarms were not widely manufactured or used until the 1970's. As detectors have become a more common presence in homes, fires—especially fatal fires—have become less and less frequent, both in New York and nationally.

In 1970, 310 people died from fire in the five boroughs; last year, only 58 did. The number of structural fires in the city last year—25,612—is about 13 percent lower than the annual average in the 1990s.

Nationwide in 2011, there were 484,500 reported structure fires that resulted in 2,640 civilian deaths—a 56 percent reduction in incidents and a 59 percent drop in deaths since 1977, according to the National Fire Protection Association.

However, at least half of the deaths in 2011 occurred in homes where smoke alarms were not functioning because the battery was either missing or deliberately disabled because of nuisance alarms.

A long-standing frustration in the fire prevention community is the disabling of smoke detectors by residents because of "nuisance alarms," most frequently set off during cooking. In addition to their weaker ability to detect smoldering fires, ionization detectors are also more likely register nuisance alarms—which means their owners are more likely to remove the battery and render the device useless when a real fire occurs.

The sole survivor of the 1990 Boston blaze that drove Fleming to study smoke detectors told investigators that the smoke alarm had been disabled because it went off too frequently from cooking.

Fleming and others believe properly placed photoelectric detectors would reduce the number of disabled devices because they are less prone to be set off by cooking smoke. Ionization detectors are also sensitive to steam from either cooking or hot showers and are frequently disabled by residents when they are located too close to a bathroom.

Councilwoman Crowley says that there are approximately 300 bills before the committee on Housing and Buildings, where New York City's photoelectric smoke detector bill is currently sitting in limbo, but she says she is hopeful it will get a hearing before this summer.

On February 27th, the Cincinnati City Council unanimously passed a similar bill after two college students died in a New Year's Day fire in that city. The new ordinance requires photoelectric smoke detectors in all rental properties and gives landlords with 12 units or less six months to comply. Owners of larger properties have two years to install the devices.

Currently Vermont requires all newly installed smoke detectors to be photoelectric. In April 2010 the state of Iowa began requiring dual-sensor units in residential dwellings. Massachusetts, which changed its statewide building code to require photoelectric detectors within 20 feet of all kitchens in 1997 has gone from ranking as the 15th out of 50 states for fire fatalities to the 3rd safest state in the country.