By Tori Mason

DENVER (CBS4) — The risk of carbon monoxide poisoning grows during colder months. The Denver Fire Department is responding to an average of three carbon monoxide related calls every day, but one in Denver’s Capital Hill neighborhood was out of the ordinary.

(credit: CBS)

“I came home one night and I heard a faint alarm, but I didn’t know where it was coming from,” said Sharon Okechukwu, “I could hear it say ‘carbon monoxide.’”

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Okechukwu recently moved into the Belmont Buckingham Apartments. She looked at the detector near her front door, but it wasn’t going off. She searched around for another alarm producing noise, but couldn’t find it.

She called 911 to be safe.

“Any amount of carbon monoxide is concerning, but anything that’s in the 15-20 parts per million (PPM) range starts to becomes dangerous,” said Lieutenant Derrick Johnson with Denver Fire.

Denver Firefighters’ carbon monoxide reader indicated that Okechukwu’s apartment was at 22 PPM. They had her evacuate until it was safe to come back. During that time, firefighters couldn’t figure out where the mysterious alarm sound was coming from.

Denver Fire found the high levels were the result of a faulty oven, but Okechukwu had not used it in days. She had her building’s maintenance team inspect it.

“When the building got renovated a lot of the units had new ovens installed. Maintenance said the valve wasn’t adjusted for high altitude. Mine wasn’t the first one they had to fix,” said Okechukwu.

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She wonders why maintenance didn’t inspect all new ovens following their initial fix.

Okechukwu also told maintenance about the faint alarm sound she heard when her carbon monoxide levels were high. She was certain they were coming from the ceiling area near the kitchen. She convinced maintenance to break through the drywall.

Buried inside a newly added wall was the old carbon monoxide detector.

(credit: CBS)

“I’ve never come across that in my 26 years,” said a firefighter who responded to the apartment. “This is concerning because the levels are going to be higher out here, than they are seeping into the walls. It’s lucky she heard it all.”

Denver Fire said it would’ve only been a few more hours before she got sick.

“I didn’t think much of it at first, but this could’ve been really bad. It took a detector that was buried in the wall to alert me of the carbon monoxide in the apartment. That’s concerning,” said Okechukwu.

She worries about her neighbors with the same renovations who might not have heard their alarms.

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CBS4 and DFD reached out to the property manager, but have not heard back. DFD plans to do an inspection of the building next week.

Tori Mason