Carbon monoxide that killed Anchorage teen came from heating system boiler

Carbon monoxide that killed a teen at a South Anchorage home on Monday and sickened seven of his family members came from a heating system boiler in the garage, police said.

The Anchorage Police Department identified the deceased as 18-year-old Trevor Noble.

Firefighters said Monday Noble died at the scene, after he was reported to have suffered cardiac arrest at the family home on the 4800 block of Shoshoni Avenue off DeArmoun Road. Seven other people were taken from the home for treatment at hospitals.

APD spokesperson Renee Oistad said Tuesday night the survivors were recovering.

"The CO source appears to be a boiler in the garage," Oistad wrote in an email.

Investigators and representatives from natural gas utility Enstar were working to learn why the leak occurred.

"Essentially, they're going to have to try to duplicate what happened before they can figure out what happened," said Alex Boyd, an assistant chief with the Anchorage Fire Department.

Asked if the home had functioning CO detectors, Oistad said "it does not look like there were."

Municipal property records show the affected home is owned by Brenda and Steven Noble.

Ben Clayton, a retired AFD captain who lives near the home, said Monday the Nobles — Steven and Brenda, plus their six children — were members of the Church of Latter-Day Saints, the same chapel his wife attends.

"They're excellent neighbors, good folks," Clayton said.

Trevor Noble attended South High School, said Anchorage School District spokesperson Heather Marron. Classmates at the school wore green Tuesday to honor Noble, and school psychologists were on hand to support students and staff, Marron said.

During his 25 years with AFD ending in 2000, Clayton responded to a variety of carbon-monoxide calls, ranging from cars started in closed garages to outdoor barbecue grills used indoors. The most common cause he recalled, however, was blockages or damage to chimney flues.

Clayton said he was surprised the large, relatively new home had been so densely filled with carbon monoxide. As a lighter-than-air gas, he said, CO would likely have to fill much of the home's upper spaces before getting low enough to affect people in beds or chairs.

"A big home like that, you'd expect it would take a great deal of CO to saturate it," Clayton said.

Sitting at his home Monday, Clayton said he was "stunned" by the event.

"It's awful — it's just awful," Clayton said.

CO poisoning prevalent in Alaska

Jan Mitchell, fire training administrator at the Alaska Division of Fire and Life Safety, said cases of carbon monoxide poisoning are widespread in the Last Frontier.

"Throughout the state of Alaska we have a lot of CO incidents, not just because of the cold but the kind of alternate heat sources that people use," Mitchell said. That includes use of portable generators, which can produce "100 times more CO than a typical automobile engine," she said.

A carbon monoxide fact sheet from the University of Alaska Fairbanks says several factors combine to give Alaska some of the nation's highest carbon monoxide-related fatality rates, including a trend toward smaller homes, weatherization efforts that cut off ventilation, and Alaskans' tendency to spend more time indoors.

Normal CO levels in the air of Alaska homes range between zero and 7 parts per million. Federal authorities recognize a maximum safe level of 50 ppm; 200 ppm can cause headaches and nausea, and 800 ppm can induce unconsciousness after an hour.

AFD crews reported levels of 1,000 ppm in the Shoshoni Avenue home on Monday — close to 1,200 parts per million, which is considered immediately dangerous to life and health.

Boilers, Mitchell said, pose the same threat as other appliances that burn wood, coal, fuel oil and paper of releasing CO if they fail to completely combust their fuels.

"If there's a leak in one of those fuel-burning systems, then that gets released into the atmosphere," Mitchell said. "Because it's ambient weight, it weighs about the same as oxygen, and because it's odorless and colorless people don't know it's in their homes."

Mitchell said from 2000 to 2010, Alaska averaged about 1.2 people hospitalized each year for carbon monoxide poisoning per 100,000 people. That rate, drawn from data compiled by the U.S. Consumer Products Safety Commission, was sharply above the national average of just .145 people per 100,000.

Alaska has seen a number of carbon monoxide deaths over the years, some accidental and others ruled intentional. Among them:

In December 2003, a family of five — a husband and wife, and three children aged 3 to 11 — died when a boiler at their Bear Valley home malfunctioned and filled the residence with carbon monoxide. The wife was found alive, but she died days later after being hospitalized in critical condition.

A year later, police said Diana Crapps, 37, used carbon monoxide to kill herself and her two children, 12-year-old Alexander and 10-year-old Cynthia, in a South Anchorage garage where she left her car running overnight. Police deemed the case a murder-suicide.

Van Dan Sosongkhan, 47, and Jewell Gafford, 33, died in January 2011 when they were found in a car in a Russian Jack neighborhood garage. Police said at the time the two had apparently let the Dodge Neon run inside the unheated garage to warm it up.

In November 2013, a Meadow Lakes woman succumbed to CO poisoning that also sickened her husband and their young daughter. Medics found 25-year-old Angela Hubbard dead, in a case investigators traced to carbon monoxide from a malfunctioning furnace drawn into the home by an overpowered ventilation fan.

Daniel Whitlow, 58, died in March 2015 at a cabin on Summit Lake south of Delta Junction on the Richardson Highway.

Alaska State Troopers said Whitlow was found in a generator shed filled with "nauseous fumes," believed to be CO; a wife and a female friend, who were performing CPR on him, had to be treated for suspected CO exposure.