PROVO — Laren Riedler's seizure saved her and some of her roommates' lives.

Riedler, 24, woke up Thursday morning knowing something was wrong. She just didn't feel right. She stumbled out of her bedroom door and was running into both sides of the hall when she collapsed at one of her roommate's doors and had a seizure.

Her roommate, Pamela Sawyer, 27, was about to leave for work and hadn't been feeling well either. But when she saw Riedler, she began to put two and two together.

She remembered they had turned on the furnace the night before for the first time and then it clicked for both of them: There was something wrong with the air they were breathing, and they needed to get out of the house — fast.

"I knew it was a gas leak of some kind," Riedler said.

They called their manager, sought treatment and tried to contact their roommates.

All six of them, who were living in an older house just south of the BYU campus, are being treated at Utah Valley Regional Medical Center for severe carbon-monoxide poisoning.

Marc Robins, the hyperbaric doctor who is treating the young women, said a couple of them were in very serious condition.

"Had they been left longer or the furnace gone off earlier, they might not have wakened," Robins said. "They could have easily died."

To help them get rid of the CO in their bodies, the women were receiving hyperbaric treatment at the hospital, in which they are placed in a submarine-looking chamber and given 100 percent oxygen. The pressure of the chamber is also increased as if they were going underwater.

Robins said this will hopefully force the CO out of their bodies. CO is toxic to brain and nerve tissues and can cause memory and fine motor loss in later years, he said. He said treatment after poisoning needs to happen within the first 24 hours.

CO is odorless, tasteless and colorless, so many people do not recognize they are being poisoned and often ignore the symptoms, Robins said.

That's what some of the roommates, including Rebekah DeMordaunt, 21, did. She thought she had contracted H1N1 flu and was going to take ibuprofen and go back to sleep for the rest of the day.

"What college student would think they have carbon-monoxide poisoning?" DeMordaunt said.

Robins said the symptoms of CO poisoning include headache, nausea, vomiting, loss of fine motor skills and seizure. If everyone in a house or apartment feels flu-like symptoms at the same time, he said, it may be CO poisoning.

Riedler said the only reason she recognized the symptoms is because her dad's childhood best friend died of CO poisoning.

"This really hit close to home," she said of the experience.

To try to prevent CO poisoning, Robins said, furnaces and fireplaces should be checked every year before use. He warned against bringing gas-powered equipment into a house and leaving vehicles running in a garage.

"Carbon monoxide can overcome you in as little as five minutes," he said. That's why having a CO detector in every level of a house and the garage is so important, Robins said.

Houses built after 2000 are required to have a CO detector, he said, but the women lived in an older house and didn't have one. Shortly after the incident, their house and all the houses owned by the manager had detectors installed.

"It's a little overwhelming what could have happened," Sawyer said. "So many things could have gone wrong."

e-mail: slenz@desnews.com