Carbon monoxide leak at Aloft Hotel sent 18 people to hospital

Eighteen people were given emergency treatment Tuesday after a carbon monoxide leak at the Aloft Hotel near Denver International Airport.

Aurora Fire Rescue evacuated the hotel at 6470 East 40th Circle at about 9:30 a.m. when it received reports of apparent carbon monoxide poisoning and detected elevated levels of the toxic, odorless gas on the first and second floors.

Two ambulances carried four patients each and a hotel van transported 10 more to UCHealth’s University of Colorado Hospital, where the fire department says they were in stable condition. Hospital spokeswoman Paula Freund would not elaborate on the patients’ conditions. “We can’t share that information,” she said.

Fire and rescue workers ventilated the hotel and allowed occupancy later on Tuesday. They are still investigating the cause of the leak.

Stonebridge Companies, which operates but doesn’t own the hotel, said the leak was detected after it activated a carbon monoxide detector and some guests complained of poisoning symptoms. Although the company said in a statement that the cause of the incident was identified and corrected, spokesman Andy Boian wouldn’t say what it was “because the final report hasn’t been released.”

“The safety and security of our guests and employees is always a top priority,” Stonebridge wrote in a brief statement.

Boian told The Independent that all of the victims were treated in and released from the emergency room, and none were admitted for further treatment.

Aloft’s parent company, Marriott International, Inc., hasn’t responded to inquiries. We’ll update this story if and when they do.

Aurora Fire Rescue spokesman Tony Krenz called the scope of people affected by the leak “unusual.” “We have a large city and quite a few hotels and residences. It’s pretty rare that we have to transport that many patients for carbon monoxide. It doesn’t happen all that often in the state.”

Krenz said Tuesday’s leak is a reminder of the November 2008 carbon monoxide deaths of a Denver family of four in a vacation rental in Aspen. Relatives and friends of the Lofgren family since have been involved in passing carbon monoxide legislation in Colorado, Oregon, Maine and Washington. “The quiet killer” – as carbon monoxide poisoning is often described – also claimed the lives of retired judge Roger Cisneros and his wife Adelia Cisneros in southwest Denver last September.

Records from the state Department of Public Health and Environment show that 36 people were hospitalized for carbon monoxide poisoning in 2016, the most recent year for which data is available. A brief analysis of annual data shows that hospitalizations haven’t significantly dropped since the Lofgrens’ deaths in 2008 triggered legislative and public education campaigns about carbon monoxide awareness.

“We need detectors all over,” Krenz said. “If nothing else, this is a reminder.”

Photo of the Aloft Hotel from

A recovering newspaper journalist, Susan reported for papers in California and Nevada before her 13 years as a political reporter, national reporter and metro columnist at The Denver Post. “Trashing the Truth,” a series she reported with Miles Moffeit, helped exonerate five men, prompted reforms on evidence preservation and was a finalist for the Pulitzer Prize in investigative journalism. Her 2012 project, “The Gray Box,” exposed the effects of long-term solitary confinement. The ACLU honored her in 2017 for her years of civil rights coverage, and the Society of Professional Journalists honored her in April with its First Amendment Award. Susan and her two boys live with a puppy named Hymie whom they’re pretty sure is the messiah.


  1. The hotel did not detect the carbon monoxide, hotel guests did with their own equipment. In fact, hotel staff had to be pressured to set off fire alarm.

  2. The comment regarding “all victims were treated and released from the emergency room, and none were admitted for further treatment” is false. There was in fact a victim that required further treatment due to the effects of CO poisoning and wasn’t released until the following day. Much of this story is very inaccurate, I would suggest thourough verification.

  3. That comment comes from and is attributed to the Fire Department. The hospital, which we also contacted, would give no information citing patient privacy.

  4. Unfortunately I year later this is still an ongoing issue! If staying at this hotel, strongly consider bringing your own CO detector.

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