Early last fall, nine-year-old Beverly called her grandparents to remind them of her visit that weekend. The weather reports warned of an early cold spell, so Grandpa promised to get their oil-burning furnace ready for its first use since the previous winter.

That Friday night was cold as predicted, but the heat in the house kicked on only once or twice. Saturday was frigid, but Beverly and her grandfather took the dog, DJ, to the park to play in the morning. Then Beverly went shopping with her grandmother at the mall. Later that night, she and her grandparents enjoyed a home-cooked meal and sat down to watch TV. Surprisingly, during the meal, DJ didn’t beg for any table scraps. He just lay by his food bowl in the kitchen. Grandpa said that DJ was acting odd because he was jealous of the attention being paid to Beverly. The dog eventually vomited and fell asleep in the kitchen. After dinner, Beverly started to complain of a stomachache and a headache. Grandma then said she had some nausea. Grandpa, however, felt just fine. He surmised that his wife and granddaughter had eaten some “bad” food at the mall. But then, when Beverly started to violently vomit, Grandpa decided it was time to go to the local hospital’s emergency department. When I first met Beverly, her triage note from the nurse read “Chief Complaint: The Flu.”

While I interviewed Beverly and her grandparents, her grandmother volunteered that she was feeling much better, but Beverly was still visibly ill. I then asked a simple question that helped make the diagnosis—“Is there anyone else at home who is ill?” Grandpa said, “There’s no one else, just us three.” But, thankfully, Beverly made an offhand comment that may have saved her life. She exclaimed, “Grandpa, what about DJ? He threw up before I got sick!”

Unintentional carbon monoxide (CO) exposure accounts for about 15,000 emergency department visits and 500 deaths in the US each year. CO gas from a poorly maintained oil, natural gas, propane or wood burner or other household source is odorless, colorless and tasteless. As CO levels rise in the home, nausea, headache, vomiting, dizziness and eventually death can result. The smallest person (or mammal, such as a dog or cat) usually will get sick first. That’s why DJ and Beverly were so ill. Beverly weighed 80 pounds and Grandma weighed 150. Grandpa weighed about 250 pounds, so he had not yet experienced symptoms.

Beverly received several hours of 100% oxygen by mask. Her grandmother’s CO level wasn’t as high, but she was given oxygen as well. Beverly’s grandfather’s level was negligible, so he hurried home to open the windows, rescue the dog and turn off the oil burner.

My advice: The warm months are the time to get your home heating system professionally inspected—technicians are more readily available and rates may be lower. And be sure to place a CO detector on every floor of your home. After the CO poisoning, Beverly’s grandparents did. To learn more about CO, go to www.epa.gov/iaq/co.html.