Every year, carbon monoxide kills hundreds of Americans and sickens thousands more, but there are simple steps people can take to protect themselves and their families.
The wild winds and massive power outages in the Pacific Northwest triggered what's now being described as a carbon monoxide epidemic in Washington state.
Hundreds of people were sickened by the colorless, odorless fumes after using charcoal grills and portable generators indoors to cook and stay warm.
Dozens have been treated in emergency rooms. Officials say they all were using unsafe methods to stay warm.
To demonstrate how quickly carbon monoxide can climb to dangerous levels, ABC News asked the Consumer Product Safety Commission to perform an experiment.
After a generator was turned on in a closed garage, it took just 15 minutes for carbon monoxide levels to get dangerously high.
"Just as smoke detectors have become common, CO alarms are just as important," said Julie Vallese, director of the commission's information and public affairs.
A carbon monoxide detector might have saved the seven people who were found dead in a Missouri apartment building over the weekend. Relatives of Phillip Scruggs say he was one of the victims.
"He was just a good person," said his mother, Robin Scruggs. "They should have had detectors in this building."
Furnaces, fireplaces and even refrigerators can emit carbon monoxide, which prevents oxygen from getting to the brain.
Last fall, Bob and Helen Roy were barely coherent when they called 911 from their welding shop just outside Boston.
When asked her name by the 911 dispatcher, Helen Roy said, "July 7."
In Seattle, more than 69 carbon monoxide victims have had their blood re-oxygenated in Virginia Mason Medical Center's hyperbaric chamber since Friday.
Doctors say the first signs of trouble are flulike fatigue, headaches and dizziness, progressing to impaired vision and nausea.
"It's key to treat people as soon as possible," said Dr. Neil Hampson of the Virginia Mason Medical Center. "It has the potential to be the largest storm-related poisoning of carbon monoxide."
The best way to protect you and your family is to install carbon monoxide detectors near your furnace and outside the bedrooms. They usually cost between $20 and $80.
Experts say you want to have the following things checked by a qualified technician once a year: the chimney, heating system, water heater, and other gas, oil and coal-burning appliances.
You should also have your car exhaust system checked.