Written by: Lauren Horsch, Dec 13, 2013

Eight people were rushed to two Des Moines hospitals early Friday morning after exhibiting symptoms of carbon monoxide poisoning, fire officials said.

The Des Moines Fire Department was called to the 1300 block of 11th Street after a woman telephoned emergency officials and said she’d had a headache for about four days, fire Capt. Steve Brown said.

The woman collapsed when the fire crew arrived, officials said. Three of the house’s occupants were taken to Mercy Medical Center; the other five were taken to Iowa Methodist Medical Center.

The fire department took preliminary readings inside the house and found high levels of carbon monoxide. Brown said that after the first reading, they called in the hazardous material crew and MidAmerican Energy. Once inside the house, fire crews shut off the furnace and water heater.

MidAmerican Energy is called when carbon monoxide is suspected in a house because the company’s workers have equipment that can detect the exact location of the leak, Brown said.

“MidAmerican Energy’s role with carbon monoxide events is primarily one of detection,” said Tina Potthoff, media relations manager for Mid­American Energy.

In this case, MidAmerican found that a rusty heat exchanger in the furnace caused the leak, Brown said.

The exchanger was expelling more than 500 parts per million of carbon monoxide. The usual amount of carbon monoxide in a house should be around 5 parts per million or less. If the house has a properly working gas stove, that amount can go up to 30, according to the Environmental Protection Agency.

Carbon monoxide can be a serious threat because of how undetectable it can be.

“The biggest thing about carbon monoxide — it is an odorless, colorless gas,” Brown said. Many of the symptoms that come from carbon monoxide poison are similar to the flu, which makes it hard to detect. Often, someone with carbon monoxide poisoning will have a headache, dizziness or a stomachache.

If someone suffering from carbon monoxide poisoning is awake, the person will start to feel sick, said Ron Humphrey, spokesman for the state fire marshal’s office. However, it is when someone isn’t alert when carbon monoxide becomes especially dangerous, he said.

“A lot of time you hear about people dying in their sleep,” Humphrey said.

In Friday’s case, one of the eight people taken to the hospital received hyperbaric treatment, which helps raise the levels of oxygen in the body, Brown said.

Brown and Humphrey said the leading cause of carbon monoxide poisoning is faulty heating equipment. MidAmerican Energy suggests that homeowners get equipment checked every year by a professional to ensure an accurate reading.

Another news article described the furnace as having a “rusted out” heat exchanger.