PROVO -- Six women spent Thursday and Friday in and out of a hyperbaric chamber after a problem with their heater caused serious carbon monoxide poisoning.

Brigham Young University students Rebekah Demordaunt, Molly Huish, Ashley Dean and Elizabeth DeFranco, as well as roommates Laren Riedler and Pam Sawyer, all of whom live in two apartments in the same building near 600 N. 100 East, woke up Thursday morning with flu-like systems. Riedler stumbled into the bathroom and had a seizure before Sawyer, her roommate, pulled her out of the house.

They ended up at the emergency room at Utah Valley Regional Medical Center in Provo. They went through more than six hours of breathing pure oxygen in the hyperbaric chamber to force the carbon monoxide from their bodies and reduce the risk of long-term brain and nerve damage like memory and fine motor loss all the way to seizures and severe brain damage.

The chamber saturates the body with oxygen and rids the blood of carbon monoxide in about 20 minutes, said Dr. Marc Robins, a hyperbaric medicine physician who worked with the women. All of them got into the chamber within six hours of being exposed, which gave all of them a greater likelihood of walking away without much damage other than long hours in a submarine-like machine wearing a clear hood.

"The longer carbon monoxide is reacting in the tissues, the more likely it is to leave you with some damage," he said.

Carbon monoxide is a byproduct of burning; the toxic gas is released from furnaces, fireplaces and cars. It can cause symptoms like headaches, nausea and disorientation in a matter of minutes and can be fatal if the person does not get away from the gas. The winter months make up the largest carbon monoxide poisoning season as people turn on heaters and fire up furnaces that turned faulty sometime in the off months.

In this case, wind had blown the furnace's exhaust vent closed, so the furnace was spitting the CO back into the house. Other times, birds build nests in chimneys or vents, renovation causes blockages or a furnace is breaking down, said Darren Shepherd, spokesman for Questar Gas. Starting or warming cars up in the garage, even if the door is open, or bringing barbecue grills into the house also are causes for carbon monoxide poisoning.

This time, the women were lucky, Robins said. All of them woke up and five were out and went to the BYU health center before going to the ER. Demordaunt, who woke up, vomited and went back to sleep on the couch, was the only one home after the health center called 911 to report the situation.

"Next thing I know the firemen are pulling up and a fireman walked in the back door," she said.

Riedler, who had the worst reaction, said she realized something was off when she was stumbling around the house and seizing in the bathroom. But not until she collapsed in Sawyer's doorway did her roommate, who also felt sick, realize there was something toxic in the air and they needed to get out. She dragged Riedler out of the apartment.

"We probably should have called 911," Riedler said Friday. "We weren't thinking straight. It's one of the things that happens when you have carbon monoxide poisoning."

All six women seemed fine Friday afternoon; they were excited to be done with the hours of oxygen-rich therapy and the hyperbaric chamber. Robins said their chances of walking away with little to no damage is good because they got treatment so quickly.

It easily could have been fatal, though, had it happened during the night when there was a smaller chance the girls would have awakened. That is why every house should have at least one carbon monoxide detector and homeowners should get the furnace checked out before turning it on this winter.

The other danger, he said, is that the symptoms in CO poisoning look almost identical to flu symptoms, minus the fever. He's worried people will not recognize the real problem.

"If the whole household comes down with the same symptoms at the same time, think carbon monoxide before you think flu," Robins said.

People who have been exposed should go to the emergency room for treatment, he said. Last year, 35 people went to UVRMC, the only hospital in the county with a hyperbaric chamber, and 16 people have gone so far this year.