Avon, CO – Almost two dozen people from four families were treated for carbon monoxide exposure Thursday.

The 23 people from four families were staying in a multi-family home complex in Avon. All were treated at the Vail Valley Medical Center and released. No major injuries were reported.

The source of the carbon remains unknown, but officials are investigating, said Gail MacFarland, of the Eagle River Fire Protection District.

What happened Thursday

Three people woke up Thursday morning complaining of headaches and nausea, MacFarland said. All three went to the Vail Valley Medical Center and were found to have been exposed to excess amounts of carbon monoxide.

The hospital asked the Eagle River Fire Protection District to check it out, and investigators found two more people suffering with carbon monoxide symptoms.

Those two were taken by ambulance to the hospital. Eventually, 18 more people were examined at VVMC. All were found to have symptoms stemming from carbon monoxide exposure.

Since Dec. 4, Eagle River firefighters have had 13 carbon monoxide calls. In some of those calls nothing was found, but not all, MacFarland said.

True carbon monoxide cannot be smelled, said George Wilson, planning director with the Eagle River Fire Protection District. Gas companies put substances in it so you can smell it, but the most certain way to know it’s there is with a carbon monoxide detector, Wilson said.

“Carbon monoxide displaces the cells’ ability to get oxygen,” he said.

Symptoms include dizziness, weakness, nausea, vomiting and headaches.

Firefighters have equipment that detects and measures various gases in the air, including carbon monoxide, Wilson said.

For carbon monoxide, 20 parts per million is considered acceptable, but not for an extended period of time, he said. He said he has seen it reach thousands of parts per million.

“Typically within a household you’ll have multiple heating and cooking systems that, if it’s not maintained, can cause carbon monoxide,” Wilson said.

He suggested households should have carbon monoxide detectors available from local stores.

“If you don’t have one of those, you won’t know it’s there,” Wilson said.

The source of the carbon monoxide in Thursday’s leak was being investigated but no source had been determined. A thorough inspection was conducted by an Avon building official who found no problems with any gas fueled appliances, MacFarland said.

The source of the carbon monoxide remains under investigation, and carbon monoxide detectors have been installed in the house. Carbon monoxide detectors can be purchased at local hardware stores, Wilson said.

Eagle River Fire Protection District, Eagle County Paramedic Services, Red Cross, Eagle County Emergency Management, Avon Police Department and town of Avon building officials responded to the scene.

About carbon monoxide poisoning

According to Eagle County Environmental Health Department, carbon monoxide is produced whenever any fuel such as gas, oil, kerosene, wood or charcoal is burned. If appliances are not working properly or are used incorrectly, exposure to dangerous levels of carbon monoxide can result.

Improperly vented furnaces, boilers and water heaters are common sources of indoor carbon monoxide problems. The proper use and maintenance of your fuel-burning appliances will lower your risk of carbon monoxide poisoning, Wilson said. According to the Centers for Disease Control, more than 400 people die in the U. S. from accidental carbon monoxide poisoning annually.