Carbon monoxide (CO) may be colorless and odorless, but it is far from harmless. Unfortunately, the toxic gas is virtually undetectable without a carbon monoxide alarm. Many people unknowingly come into contact with potentially dangerous levels of CO every day. Below, learn what factors in your home may expose you to carbon monoxide, as well as the best ways to protect yourself from it.

What is carbon monoxide and why is it dangerous?

Carbon monoxide is formed by the incomplete combustion of fuels such as wood, coal, propane and natural gas. Carbon monoxide can be toxic when inhaled. As it enters the bloodstream, it can prevent your body from effectively absorbing oxygen, resulting in tissue damage and eventual death.

According to the CDC, more than 20,000 people visit the emergency room each year due to carbon monoxide poisoning. While no one is immune to the effects of this toxic gas, certain people, such as infants, the elderly and those with heart or respiratory conditions, are more sensitive to the effects of CO poisoning.

Symptoms of carbon monoxide poisoning

Because of the nature of the symptoms of CO poisoning, many people often mistake their symptoms for signs of the flu. However, unlike the flu, symptoms of carbon monoxide poisoning will clear up when you leave the area of the CO leak.

The EPA states that some of the most common symptoms of CO poisoning are:

Fatigue in otherwise healthy people

Chest pain in people with heart conditions

Angina

Impaired vision and coordination

Headaches

Dizziness and confusion

Nausea

Other flu-like symptoms

At higher concentrations, CO poisoning can make you pass out and can even be fatal.

If you experience any of the symptoms listed above — or suspect that there might be a carbon monoxide leak in your home — you should leave your home immediately, get fresh air and call a poison control center at 1-800-222-1222. They will help you determine whether you need to seek further medical attention. You should also call your local fire department or gas company to find and fix the source of the leak.

Note: It is possible to breathe unsafe levels of CO without showing any symptoms, according to the EPA. Breathing in low concentrations of CO over time can cause long-term adverse health effects such as neurological impairments as well as sensory and motor disorders.

Where might carbon monoxide show up in my home?

Carbon monoxide is created by the burning of fuels, so houses with fuel-burning appliances and attached garages are more susceptible to carbon monoxide leaks. Some potential sources of CO are:

Stoves and kitchen ranges — Gas stoves and kitchen ranges can be a source of carbon monoxide in your home, especially when they are used without proper ventilation, such as a range hood. To help prevent this, keep your stove and kitchen range clean and in proper working condition.

— Gas stoves and kitchen ranges can be a source of carbon monoxide in your home, especially when they are used without proper ventilation, such as a range hood. To help prevent this, keep your stove and kitchen range clean and in proper working condition. Fireplaces — During the winter months, some people may choose to use their fireplace as an alternative source of heat. The smoke from the burning wood could accumulate in your home, increasing the concentration of carbon monoxide and other dangerous particulate matter in your air. Always open your flue when using a fireplace.

— During the winter months, some people may choose to use their fireplace as an alternative source of heat. The smoke from the burning wood could accumulate in your home, increasing the concentration of carbon monoxide and other dangerous particulate matter in your air. Always open your flue when using a fireplace. Grills — Never use a grill in an enclosed space, such as a garage. The CO formed from the burning fuel can accumulate to toxic concentrations.

— Never use a grill in an enclosed space, such as a garage. The CO formed from the burning fuel can accumulate to toxic concentrations. Furnaces, dryers, water heaters and space heaters — In some homes, these appliances are powered by burning fuel. Without proper ventilation, inspection and maintenance, these appliances could emit CO into your home. Like other air pollution concerns, carbon monoxide poisoning tends to happen more often during the extremely cold months of winter.

— In some homes, these appliances are powered by burning fuel. Without proper ventilation, inspection and maintenance, these appliances could emit CO into your home. Like other air pollution concerns, carbon monoxide poisoning tends to happen more often during the extremely cold months of winter. Portable generators — Gas-powered portable generators can be especially dangerous because they produce high levels of carbon monoxide when in use. To be safe, always use a portable generator outside, at least 25 feet away, and downwind, from any open windows or doors.

— Gas-powered portable generators can be especially dangerous because they produce high levels of carbon monoxide when in use. To be safe, always use a portable generator outside, at least 25 feet away, and downwind, from any open windows or doors. Tobacco smoke — Cigarettes can be another source of carbon monoxide for both smokers and the people that they come in contact with. When you smoke a cigarette, you directly inhale a portion of the CO created from the combustion that occurs when the tobacco within a cigarette is burned. Additionally, smoking can increase ambient CO levels, especially in an enclosed room, increasing CO exposure for people who are not smoking.

— Cigarettes can be another source of carbon monoxide for both smokers and the people that they come in contact with. When you smoke a cigarette, you directly inhale a portion of the CO created from the combustion that occurs when the tobacco within a cigarette is burned. Additionally, smoking can increase ambient CO levels, especially in an enclosed room, increasing CO exposure for people who are not smoking. Cars, RVs and other vehicles — Many vehicles require fuel combustion to operate. Many people like to run their cars for a few minutes inside the garage on cold mornings. However, this practice can potentially cause an unsafe accumulation of CO in your garage and even inside certain areas of your house. Even in a detached garage, you should always have the garage door open when running a vehicle. Additionally, you should have your exhaust system checked once a year for any potential leaks that could cause a CO buildup inside the car.

Where might carbon monoxide show up in an apartment?

While potential sources of carbon monoxide in an apartment can be similar to those found in a house, there are a few key differences that you should be aware of. For example, you may not have to worry about vehicle exhaust accumulating in your home, but you do have to consider the actions of the other people living in your building.

You should still be mindful of the potential CO sources listed above, but additionally, you should consider:

Other tenants — Other residents in your building may burn open fuels, especially during the cold months when temperatures drop for the winter. Additionally, any excessive CO levels (no matter the cause) can enter your apartment through the ventilation system.

— Other residents in your building may burn open fuels, especially during the cold months when temperatures drop for the winter. Additionally, any excessive CO levels (no matter the cause) can enter your apartment through the ventilation system. Ventilation — Increasing the ventilation in an apartment can be tricky if you share one or more walls with other units in the building. With fewer windows and doors, your options for increasing air flow may be limited. Pay special attention to the ventilation in your apartment when you are cooking or doing other activities that may cause CO emissions.

Lanterns and space heaters — Powered by burning fuel, these should never be used in an enclosed space. Lanterns and space heaters have the potential to release high levels of CO that could rapidly accumulate in an enclosed area.

— Powered by burning fuel, these should never be used in an enclosed space. Lanterns and space heaters have the potential to release high levels of CO that could rapidly accumulate in an enclosed area. Gas-powered appliances — This can include your stove, kitchen range and furnace, outlined in greater detail in the list above. Because apartments are typically smaller than houses, you should take extra care to keep your space well-ventilated.

How do we protect ourselves from carbon monoxide poisoning?

Unfortunately, you cannot see or smell carbon monoxide, so a quality CO detector is the only way to be certain that you are not breathing in the dangerous gas. According to the Consumer Product Safety Commission, you should install at least one CO detector in every level of your home or apartment. Detectors should ideally be placed in hallways, outside of all bedrooms and should be checked every month.

Today, many combination CO detectors and smoke alarms are available on the market. These alarms will sound when they detect smoke or potentially dangerous concentrations of carbon monoxide. The CPSC recommends using CO alarms that meet the most recent Underwriters Laboratories (UL) 2034 standard. All units that meet this standard should have the UL symbol somewhere on the packaging.

If you live in an apartment, your state may require your landlord to have a functioning CO detector in your unit. Even if your state does not require the installation of CO alarms, you can also check to see if your city or municipality does. If an alarm is not installed, you have the right to ask your landlord to provide one.

No matter whether you live in a house or an apartment, you should check your gas-powered appliances regularly to ensure that they are working properly and not emitting CO. If possible, install an exhaust fan over your gas stove that vents to the outside. Remember, many gas-powered appliances work even when the electricity is off, so turning off power to your house is not an effective way to stop a CO leak.

If you suspect that you may have a carbon monoxide leak, do not hesitate to call your local gas company. They will happily check your equipment to make sure that it is safe, and they will do it at no charge. If you live in an apartment, your landlord may be required to fix any gas-powered appliances or equipment that cause safety issues.

Because carbon monoxide is odorless, colorless and highly toxic, it can seem like a scary adversary. However, you are far from defenseless against CO poisoning, especially if you familiarize yourself with the potential sources of CO in your home. With a functioning carbon monoxide detector and regular maintenance of gas-powered appliances and equipment, keeping your home or apartment safe from carbon monoxide can be simple!