Indoor Air Quality

Do You Have the Flu or Carbon Monoxide Poisoning?

Today, carbon monoxide (CO) is the most commonly encountered and pervasive poison in our environment. Each year thousands of people seek medical attention or lose several days of normal activity; more than 500 people die through unintentional exposure, and as many as 2,000 people commit suicide using CO according to Dr. David Penney of Wayne State University. A professional inspection of all gas equipment in your home could save your life and the lives of your loved ones. Flu and bad cold systems such as headaches, nausea, pains, and mental confusion may actually be caused by gases in your home.

There are two kinds of dangerous gas that can leak into your home. One you can smell, and one you can’t smell.

You probably know that if you “smell gas” you should immediately shut down your furnace, heater, or cook stove and call for help. This is the gas that is delivered to your home from the gas company through the pipeline or from your propane tank. There is a special chemical put into these gases to make them smell like rotten eggs so you will be sure and notice if there is a leak. If this gas were to build up in your home, it could explode and destroy your home.

The other dangerous gas is actually produced inside your home. It is produced as a result of incomplete burning of carbon-containing fuels including coal, wood, charcoal, natural gas, and fuel oil. It is produced by incomplete combustion or poor ventilation of fuel-burning appliances such as oil or gas furnaces, gas cooking appliances, water heaters, fireplaces, or wood stoves. This gas is the same toxic gas that comes out of the tail pipe of your car if you leave it in a closed garage with the engine running. It is called carbon monoxide. Carbon monoxide is an odorless, colorless gas that interferes with the delivery of oxygen in the blood to the rest of the body. Even though carbon monoxide will not explode, it can be dangerous (even deadly) to you and your family.

Two common sources of carbon monoxide in homes in Texas are the gas furnace heat exchanger and the gas hot water heater. As homes have been built to be more energy efficient, the have fewer places where fresh air can leak into the home. In order for fuel-burning equipment to operate correctly and safely, it much have a source of fresh air for complete combustion. If the fresh air is not available, the equipment will pull the combustion gases back into the house rather than exhausting them up the flue. Carbon monoxide can also be emitted by combustion sources such as unvented kerosene and gas space heaters, fireplaces, gas stoves, wood stoves, automobile exhaust from attached garages, and tobacco smoke.

There are things you can do to protect yourself and family. These include:

  1. Have your furnace checked and adjusted by a professional to be sure the burner and vent systems are operating properly and that the heat exchanger has no cracks.
  2. Visually inspect the area around your furnace to make sure there is enough air flow for the burner to bring in fresh air. The furnace should not be in a tightly sealed space.
  3. Inspect both the water heater and furnace flue for internal obstructions or leaks around the joints.
  4. Test a gas water heater while the burner is on by holding a lighted match under the draft hood. A match that flickers downward or goes out may indicate an exhaust backflow. The flame of the match should burn upward toward the flue.
  5. Burn the fireplace or wood stove with the damper open so that all combustion gases will flow to the outside.
  6. Never use a gas stove for heat.
  7. Do not leave an automobile or lawn mower running in a closed building, especially an attached garage. Carbon monoxide can drift into the home.
  8. Follow safety precautions and directions when using combustion equipment in a home. Problems arise as a result of improper installation, maintenance, or inadequate ventilation.
  9. Secure carbon-monoxide detectors and place at least one near the sleeping area and others near the fireplace, furnace, and any other fuel-burning appliances.
  10. Select a detector that has Consumer Product Safety Commission and Underwriters Laboratories’ seals of approval.
  11. If a carbon monoxide detector activates, call the fire department. They have sensing equipment to determine where dangerous levels of carbon monoxide are located. Since home detectors are made to alert before the environment is hazardous, this gives the homeowner a chance to contact the appropriate service personnel to “fix” the problem.
  12. If any person in the area when the alarm sounds has an extreme headache, nausea, flu-like symptoms, or disorientation, they should be transported to the nearest emergency care facility and checked for carbon monoxide poisoning.


  • “Protect Your Home: What You Need to be Safe and Secure.” Consumer Reports. May 1994. Yonkers, New York: Consumers Union of U.S., pp. 322-343.
  • “Home...Safe and Secure Consumer Decision Making!” Handout created by Dr. Lynn White, Professor and Extension Family Economics Specialist, Texas A&M AgriLife Extension Service, Texas A&M System, March 1995.
  • “A Safe Home is No Accident.” A Family Checklist provided by Easter Seals and Century 21 Real Estate Corporation.
  • “Your Home Fire Safety Checklist.” U.S. Consumer Product Safety Commission, Washington, D.C.
  • “Your Source of Information On a Major Deadly Poison and Related Gaseous Poisons.” David G. Penney, Ph.D., Wayne State University, School of Medicine.

[back to top]

Housing and the Environment logo

Prepared by Janie L. Harris, M.Ed., CRS, former Extension Housing and Environment Specialist, Texas A&M AgriLife Extension Service, Texas A&M System. 1999.

Last updated: 22 November, 2013

Educational programs of the Texas A&M AgriLife Extension Service are open to all people without regard to race, color, sex, religion, national origin, age, disability, genetic information or veteran status.