This is an archived article that was published on sltrib.com in 2013, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.

Sarah Mah did not feel sick as her house filled with poisonous gas.

A couple of weeks ago, the Salt Lake City woman and her boyfriend were making some evening tea at their home near 9th and 9th when the carbon-monoxide alarm went off. Besides the baby in her womb, Mah was concerned for her best friend's three children spending the night. A quick web search told Mah to call 911 and get everyone out of the house.

The alarm saved everyone. As winter approaches and people seal their homes, stay inside and look for ways to warm up, Cristal VanDongen of the Salt Lake City Fire Department has some simple advice that could save your life: First, install carbon monoxide alarms and, second, replace aging units.

Carbon monoxide is a colorless, odorless gas that can be produced by heaters, fireplaces, furnaces and other gas- or fuel-burning appliances and stoves. Only by using an approved carbon-monoxide sensor and alarm unit can dangerous levels of the gas be detected.

Otherwise, VanDongen warns, carbon monoxide, even at low levels, can sicken you and, at higher levels, kill you.

In Mah's case, the poison was spilling from a refurbished stove that she and her boyfriend bought recently. When the firefighters arrived and tested the house, they discovered the concentration had reached 70 parts per million. Half that much starts affecting people.

The signs begin with flulike symptoms, which turn to dizziness and confusion, and then you black out. As carbon monoxide bonds with the hemoglobin in your blood, it prevents oxygen from bonding to it. Once enough carbon monoxide is in your system, VanDongen said, you still cannot breathe even if you get outside and are surrounded by clean air.

Under state law, homeowners and landlords are required to install carbon-monoxide-detection units in all buildings that contain bedrooms or sleep areas and use fuel-burning appliances.

However, because the detection units' life span is only five to seven years, it is imperative that old units be replaced with new ones.

In light of their run-in with the poisonous gas, Mah and her boyfriend bought a second alarm. Everyone is all right, including the children who were asleep as the gas filled the house.

"We're super-safe," she said. "I've told everyone I can [to buy one]."

The gas is greatest source of accidental poisonings in the city. The fire department had 21 carbon-monoxide calls last year — excluding false alarms. To VanDongen's knowledge, none turned fatal.

Earlier this year, a Questar technician saved a Kearns man's life from the gas.

The man's sister smelled something weird in the air and called Questar Gas. When the technician arrived, his carbon-monoxide monitor went off, showing a reading of 800 parts per million, "the highest I have ever seen it," Unified Fire Authority Capt. Clint Mecham said at the time, speaking from 10 years of hazardous-material experience.

The technician got the woman out, but when he went back inside to check on her brother, he found him unconscious in a basement room. So he carried him out.

For more information about carbon-monoxide safety, visit the FirstAlert.com website.

Twitter: @remims

Twitter: @mikeypanda