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Hours: Mon-Fri 8 a.m - 5 p.m.


Crystal Stilwell
911 for Emergency Assistance


What is Carbon Monoxide?

Carbon Monoxide (CO) is a lethal poison that is produced when fuels such as gasoline are burned. It can rapidly accumulate even in areas that might appear well ventilated. Because CO is colorless, tasteless, odorless and non-irritating, it can overcome an exposed person without warning. It frequently produces weakness and confusion, depriving the person of the ability to seek safety.

From where does carbon monoxide gas originate?

  • Vehicles and any other combustion engines running in an attached garage – even when an outside door is open (Remember: Never leave a car running in the garage)
  • Any fuel-burning appliance that is malfunctioning, such as furnaces, gas range/stove, gas clothes dryer and water heaters (Remember: Always properly install gas range)
  • Fireplaces, charcoal grills and wood-burning stoves (Remember: Never grill indoors)
  • Blocked chimney or flues (Remember: have them checked at least once a year)

Is it safe to briefly warm up a car in an open garage?

No. In an Iowa State study, warming up a vehicle for only two minutes with the overhead door open raised CO concentrations in the garage to harmful levels. Ten hours after the car had been backed out of the garage, there was still a measurable concentration of CO in the garage. Persons working in the garage for a long period of time would breath a dangerous amount of CO.

How can I protect myself from CO exposure from vehicles in my attached garage?

Carefully maintain the vehicle and never warm-up or operate a vehicle in the garage or other enclosed area, even if the garage door is open. Also, a sufficiently sized exhaust fan designed and installed by a qualified contractor will prevent CO from entering the house and speed the removal of CO from the garage. However, even with a garage fan it is not safe to operate an engine in the garage. 

What is downdrafting?

Downdrafting is flow reversal in a vent pipe or chimney. Outside air enters the house through the vent, and hot combustion gases spill into the home. Anything that moves air out of a house and depressurizes the house can cause downdrafting. This includes exhaust fans, any vented heating appliance, fireplaces, even holes in the ceiling. Vents in tight homes are especially susceptible to downdrafting.

When should CO poisoning be suspected?

    • Entire family is sick at the same time
    • Flu-like symptoms decrease while away from the house
    • Illness is present when gas appliances are in use
    • Excess moisture on the interiors of windows

What should be done for someone who suffers from CO poisoning?

They should immediately be moved into fresh air and medical authorities consulted.

Can I be tested for Carbon Monoxide?

Yes. If you have recently been exposed, a breath test can determine CO levels.

Why do I need a Carbon Monoxide alarm?

The U.S. Consumer Product Safety Commission identified Carbon Monoxide as the leading cause of gas poisoning deaths in the U.S.  Thousands of cases of illness, brain damage and death could be prevented if all homes had CO alarms. 

What type of alarm should I purchase?

Choose an alarm listed with the Underwriters Laboratory (UL) or Canadian Approval Services (CAS).  The alarm sounds a shrill warning before the levels of Carbon Monoxide become immediately dangerous.  Alarms cost $30 to $80. 

What are some features to check before I buy?

  • AC or battery operation
  • UL or CAS Listing
  • Purchase price
  • Yearly sensor and/or battery replacement cost
  • Consumer evaluations
  • Reliability of the company
  • Reset features and time it takes to reset and clear
  • Digital readout
  • Capacity to be wired with other alarms
  • Sensitivity
  • Memory and peak level functions 

Where do I place my CO alarm?

Carbon Monoxide is lighter than air.  CO2 and O2 are products of complete combustion, CO is produced when there is incomplete combustion.  If all 3 gases are spilled into an area the CO2 Carbon Dioxide will drop to the floor and the lighter CO Carbon Monoxide will always rise to the ceiling.

Another way to explain this is to compare it to smoke from a fire.  Visible smoke from a fire is a particulate which is heavier than air, but it rapidly rises to the ceiling because of the heat.  The same applies for CO spilled from an appliance, it will rise to the ceiling and will always be at a higher concentration near the ceiling.

Molecular weight of:

Carbon Monoxide----->28.01 Lighter




Carbon Dioxide------->44.01 Heavier

Alarms should be located near each sleeping area.  It can be placed anywhere on the wall from floor to ceiling.  The alarm must be located where Carbon Monoxide can reach it, and where it will awaken persons sleeping in the dwelling.  Homes with several sleeping areas will require multiple alarms.  Locate additional alarms near fossil fuel appliances.  Do not locate an alarm in a garage, kitchen or furnace room. CO alarms should be at least 15 feet from the furnace, water heating or cooking appliances.  Do not mount them in dusty, dirty or greasy areas, or in extremely humid areas.  Read and follow installation instructions furnished with the alarm. 

What should be done if an alarm sounds?

EVACUATE and call 911.  Make certain to account for everyone. Let the Fire Department determine if there is Carbon Monoxide in the home.  If there is no CO present, follow directions supplied with the alarm. 

What do I do if there is Carbon Monoxide in my home?

DO NOT IGNORE THE ALARM. Find out what caused the alarm.  Contact your heating contractor for help in tracking down the CO source.  Do not assume that because you cannot see, taste or smell anything, that there is no problem.  CO has no color, taste or odor.  Episodes of CO leakage can be sporadic and hard to detect.  Be persistent.  Field studies indicate there are few, if any, "false" alarms.  Be certain there is always an operating alarm in any house where an alarm has sounded.  It is important to respond to the alarm before continued exposure disables the occupants. 

How do I know if the concentration is low or high?

Most CO alarms emit a loud, annoying sound.  Alarms listed by UL sound only at levels above generally accepted safety levels.  You will hear it.  Some alarms have a digital readout, which reports the CO levels.  But very low CO levels, those which cause chronic health problems, must be measured using professional instruments.  Still other alarms have a color sensor, which can be evaluated by trained technicians. 

How do I maintain and test the alarm?

Consumers should follow the manufacturer's instructions. Using a test button, some detectors/alarms test whether the circuitry as well as the sensor which senses CO is working, while the test button on other detectors only tests whether the circuitry is working. For those units which test the circuitry only, some manufacturers sell separate test kits to help the consumer test the CO sensor inside the alarm.  In general, most alarms should be vacuumed at least twice a year, and tested every week. 

 What has changed in CO detectors/alarms recently?




What building permits are covered in the regulations?

In Section VII (a) of the ordinance there is an effective date of January 1, 2001 for dwelling units and child care facilities for which Building Permits are issued. The Regulations deal with new buildings that receive a building permit to be constructed after January 1, 2001. It also includes building permits for change-outs from electric to gas, since that is a situation where the new construction causes the property to fall into the category that needs the CO alarm. Building permits for other renovations or additions to existing structures are not included in the requirement. However, if the existing structure needed a CO Alarm and did not have one, it would be non-compliant and a violation letter could be issued requiring compliance within 30 days.


Hours: Mon-Fri 8 a.m - 5 p.m.


Crystal Stilwell
911 for Emergency Assistance