Updated: Apr 26
As the weather gets warmer, our thoughts turn to spending more time outdoors, packing away our winter items, and bringing out summer gear. As you spend time prepping for warm days ahead, you should also keep carbon monoxide safety in mind. Outdoor activities are often times to have fun, but they also carry a danger of carbon monoxide poisoning. Learning about these dangers and how to prevent carbon monoxide poisoning is an important step in staying safe during your time outdoors.
The bottom line:
Carry a portable carbon monoxide detector during outdoor activities
Ensure properly functioning carbon monoxide alarms on boats and in RVs
Move to a safe area if carbon monoxide poisoning is suspected
Never use barbecues, grills, or unvented fuel-burning appliances indoors
Remain 20 feet away from carbon monoxide-emitting equipment
Be aware that carbon monoxide can build up to dangerous levels even outdoors
About Carbon Monoxide Poisoning
Carbon monoxide is a colorless, odorless gas, which is produced anytime there is incomplete combustion of a fuel, so your risk of carbon monoxide poisoning increases during the use of fuel-burning/combustion equipment.  Well-designed and maintained combustion equipment should have low levels of incomplete combustion, but they won’t be eliminated completely. This means there is still a risk of carbon monoxide poisoning from these items, which is even greater if they are not being used correctly or functioning properly. Even outdoors, carbon monoxide can accumulate to levels that cause acute and chronic carbon monoxide poisoning.
Acute carbon monoxide poisoning is caused by high levels of carbon monoxide and leads to death or severe injury within a short time of exposure. Chronic poisoning also poses significant danger. Chronic carbon monoxide poisoning occurs from long-term exposure to low levels of carbon monoxide and is linked to heart failure and neurological impairments. It is often hard to recognize while it is occurring  and you may not experience symptoms even when a situation is unsafe. Safety measures should be taken well before carbon monoxide poisoning is even suspected.
There are several preventative measures you can take against carbon monoxide poisoning. Universal measures include carrying a high-sensitivity portable carbon monoxide detector, regularly testing carbon monoxide detectors, keeping combustion equipment well-maintained, and only using non-vented equipment, such as generators, outside in well-vented areas. Further safety measures will depend on the situation. Listed below are some carbon monoxide-emitting items you might encounter during your time outdoors and the steps you can take to be safer around them.
Outdoor Safety Practices
Barbeques and grills
Fuel-burning lawn equipment (leaf blowers, lawnmowers, trimmers/edgers, brush cutters, etc.)
Torches and lanterns
Limit the duration of use of fuel-burning/combustion equipment and never use them indoors.  Be cautious when using these items in corners or in tight spaces as they are more likely to create a build-up of carbon monoxide, even without overhead cover. As recommended above, keep equipment well-maintained to keep emissions low,  reducing the likelihood of a dangerous situation. Carry a portable carbon monoxide detector while using this equipment. The detector will inform you of any elevated levels of carbon monoxide, giving you the opportunity to turn off the equipment and move to an area with clean air.
Consider switching to any electric alternatives available for these items. These electric tools eliminate carbon monoxide emissions and as a bonus are often quieter than their combustion counterparts.
Fuel-burning camping stoves and heaters
You likely have had many experiences around campfires, but you may not have realized that it is a source of carbon monoxide. To avoid breathing in carbon monoxide, keep a fair distance between yourself and the fire.
Never use a camping stove that burns fuel for power inside, including inside your tent. Carbon monoxide can accumulate quickly inside leading to injury or death.  You are especially vulnerable while sleeping as you will not be aware of symptoms, which might have otherwise alerted you to a problem. Using a portable carbon monoxide detector on your trip is a great way to ensure you are aware of the carbon monoxide levels at your campsite and are alerted to danger even while asleep.
Camping typically means having limited resources and some types of equipment might not be suitable for this endeavor. However, if electric camping heaters and stoves will fit your camping style, their use is recommended as these electric alternatives produce no carbon monoxide.
On the boat
Swimming near boats
Boating can be dangerous in many ways, one of which is the risk of carbon monoxide poisoning. Situations involving carbon monoxide on a boat can be very serious. Exhaust from your own boat and any nearby boats can lead to rising carbon monoxide concentrations on deck and in the area surrounding the boat. This creates a dangerous situation for anyone on the boat, in the water nearby, being towed, or on a neighboring boat. Carbon monoxide accumulation is more likely during slow speeds and idling. 
To decrease your risk of carbon monoxide poisoning while boating:
Do not swim near any boats with engines running 
Give a long length between the boat and anyone being towed (keeping in mind laws which dictate limits on tow distance)
Reduce idling time and stay clear of groups of idling boats. The CDC recommends keeping a distance of 20 feet from a running boat 
Install a carbon monoxide alarm on your boat and test it regularly to ensure it is functioning properly 
Monitor passengers for symptoms of carbon monoxide poisoning and get to a safe area as soon as a problem is detected
Unfortunately, there have been several instances of deaths from carbon monoxide on boats, including the death of 9-year-old Andy Free in 2020. Andy had spent the day on the lake with family and friends. The group was doing watersports and stopping frequently. By the end, some of the kids were disoriented, and, devastatingly, Andy fell off the boat and was unresponsive in the water. His death was determined to be from carbon monoxide poisoning. Andy’s mom, Cassi, used this experience as motivation to provide support in the creation of a bill, which would require carbon monoxide warning stickers on boats in Oklahoma.  These types of incidents can be prevented with increased understanding of the dangers of carbon monoxide while boating and the implementation of safety measures to reduce risks of carbon monoxide poisoning.
Spending time outdoors often means spending time next to vehicles. Large crowds of vehicles might form at sports games, concerts, or other events. This density of combustion-powered vehicles can lead to high concentrations of carbon monoxide. In these situations, avoid running vehicles when possible and be aware of any nearby vehicles that might be running so you can stay clear of their exhaust.  Even a single running vehicle can emit enough carbon monoxide to cause injury. Do not stand downwind of exhaust and keep distance between you and the vehicle to avoid breathing in carbon monoxide.
RVs pose additional risks of carbon monoxide poisoning due to the presence of fuel-burning equipment within or near the RV. This includes fuel-burning stoves, ovens, fridges, and generators, as well as any other combustion devices. Never use a generator inside of an RV. These items are mostly designed to be vented outside (gas stoves rely on the use of vent hoods to move exhaust from the indoor space), but the area outside the RV can experience an accumulation of carbon monoxide from these exhausts.
To make conditions less suitable for build-ups of carbon monoxide around the RV, choose a parking location that is clear of any objects which could block the flow of air or exhaust.  Divert exhaust above the roof. This can be accomplished with the installation of exhaust stacks. 
Carbon monoxide may also accumulate within the vehicle itself, making the installation of a carbon monoxide alarm in your RV as critical as it is for your home. Check that it is functioning before all trips and replace batteries when necessary per the manufacturer. Never use stoves or ovens to heat your RV as this can lead to high levels of carbon monoxide very quickly.
These measures can help prevent a situation like one in 2021, which left two people in critical condition and led to the deaths of three others. The group had been attending a country music festival during the summer and were camping out at the festival grounds in an RV. Many other vehicles were parked in the same area. A portable generator was being used on their RV and its exhaust was flowing underneath the vehicle. The five people were found unconscious in the RV after being affected by the carbon monoxide emitted from the generator. A carbon monoxide alarm was found in the RV but it was non-functional. [10,11] There were many factors that may have contributed to this situation. The importance of practicing carbon monoxide safety can be seen in examples like this, where one action, such as ensuring the proper functioning of a carbon monoxide alarm, could have made a difference.
Stay Safe and Enjoy Being Outdoors
Before now, you might have viewed carbon monoxide poisoning as an indoor issue. However, dangerous situations can arise anywhere there is a source of carbon monoxide. These sources are anything that burns fuel and include many things commonly used outdoors, often for recreation. Armed with this knowledge, you now have the capability to better protect yourself and your loved ones. Remaining safe outdoors requires a number of practices, but the result is that your warm days in the sun can remain joyful, the way they’re meant to be.