Cache County, UT – Cache County sheriff’s deputies are investigating the deaths of two campers who may have been poisoned by carbon monoxide emitted from a propane heater inside their tent.

A 28-year-old man and a 10-year-old girl were found around 8 a.m. Sunday in a tent near Ant Flat Road about 2 miles from the Weber County border, said Cache County Sheriff’s Lt. Matt Bilodeau.

The two were from out of state and had come to Utah for a large paintball event in the area where they were camping. Other participants found them dead when they checked the tent to let the pair know the day’s activities were beginning, Bilodeau said.

Authorities are not releasing their names, their relationship or their home state until family are notified.

Investigators believe carbon monoxide was produced by a heater that was screwed into a 5-pound propane tank, Bilodeau said. A medical examiner will determine the exact cause of death, he said. Temperatures dropped to the mid- to upper-30s Saturday night in the mountains near the paintball meet, according to National Weather Service records.

Campers often set up tents in the area of the Ant Flat Road, a dirt road that runs through the Uinta-Wasatch-Cache National Forest. There are no established campgrounds there, Bilodeau said, but as many as 200 people were camping in the area for the paintball event.

A Web site for the Scenario Paintball Players League advertises a national event for this weekend near Monte Cristo. The group is listed on the site as “an international, competitive paintball league.”

It is not clear whether the event was on private or federal land.

Doctors warn that carbon monoxide danger can increase during summer camping and boating activities.

Anything that burns fuel produces carbon monoxide, including kerosene lanterns, propane stoves, heaters, and idling cars, said Lindell Weaver, medical director of hyperbaric medicine at Intermountain Medical Center.

Carbon monoxide binds to hemoglobin, the oxygen-carrying molecule in the blood, reducing the amount of oxygen carried to other parts of the body.

“The prime target organ is the brain. The brain needs the most oxygen of any organ,” Weaver said.

The lack of oxygen causes nausea, headaches, confusion, and weakness. It also inflames the organs and brain, and continues even after the exposure ends, causing permanent injury.

A large amount of carbon monoxide can kill a person in a few minutes, Weaver said. Sleeping people are particularly vulnerable, since they can’t feel the warning signs.

“People shouldn’t be using anything that burns fuel inside a tent,” he said. The gas collects in small enclosed spaces. Take machines outside of any enclosed space, and away from people to use them, he said.

The deaths also underline the need for event planners to notify local authorities when they plan large gatherings in rural Utah, Bilodeau said.

“It’s important for the sheriff’s department and EMS to know. There could be a big fight or a problem with an animal — all kinds of things.”