Prevention of Carbon Monoxide Poisoning

A family runs a portable generator in the garage during a power outage. A furnace vent gets blocked by snow overnight. A car idles in an attached garage while warming up. Each of these common scenarios leads to carbon monoxide (CO) buildup — and each is entirely preventable. Knowing how to prevent carbon monoxide poisoning comes down to a few key habits: working CO alarms, annual appliance maintenance, safe generator placement, and garage discipline. This page provides a complete carbon monoxide safety checklist covering every major risk area, including winter-specific and travel tips.

In 60 Seconds

• Install working CO alarms on every level and near sleeping areas — test monthly and replace as directed.
• Schedule annual professional inspection of all fuel-burning appliances and venting.
• Never use a generator, grill, or fuel-burning device indoors or in a garage — even with the door open.
• Never idle a vehicle in an attached garage; exhaust can seep into living spaces.
• During storms and outages, treat generator placement as a life-safety decision.

Prevention Checklist

Use this checklist to reduce the risk of carbon monoxide exposure:

CO Alarms and Detection

• Install CO alarms on every level of your home and near sleeping areas.
• Test alarms regularly and replace batteries or units as required.
• Replace alarms at end-of-life (check the label/manual for expiration).

Appliances and Venting

• Have furnaces/boilers, water heaters, fireplaces, and other fuel-burning appliances serviced by qualified professionals.
• Ensure vents and chimneys are not blocked by debris, snow, nests, or damage.
• Use kitchen and bathroom ventilation as intended; avoid using ovens to heat rooms.

Generators and Outdoor Devices

• Use portable generators outdoors only, far from buildings and openings.
• Never use generators in garages, basements, crawlspaces, or near windows/doors.
• Never use charcoal grills or camp stoves indoors (including tents or enclosed porches).

Garage and Vehicles

• Never idle a vehicle in an attached garage, even with the door open.
• Keep doors between the garage and living space closed when possible.

Travel and Rentals

• When you arrive, locate CO alarms and ensure they appear present and intact.
• If you travel often (hotels, rentals, RVs), consider a portable CO alarm for added protection.
• Report malfunctioning heaters/fireplaces immediately and choose a different room/unit if alarms are missing.

Seasonal and Outage Safety

• During storms/power outages, treat generator placement as critical safety work.
• If using alternative heat sources, confirm they are designed for indoor use and follow manufacturer guidance.

CO Alarms: Install, Test, Replace

CO alarms provide early warning, but only if they are installed and maintained correctly. Follow the manufacturer's instructions for your specific unit, and place alarms where they can wake you at night. Test alarms on schedule and replace expired units.

Placement guide: Where to place a carbon monoxide detector. How many you need: How many CO detectors do I need?. Detection methods: How to detect a carbon monoxide leak.

Many states and cities also have CO detector requirements for homes, rentals, and sales. While legal compliance is important, treat alarm installation as a safety-first decision regardless of whether it's technically required.

Appliance Maintenance and Venting

Most home CO incidents involve malfunctioning or poorly vented equipment. Schedule professional maintenance for fuel-burning appliances, and address venting issues promptly. Do not ignore recurring pilot light problems, soot/staining, or unusual combustion behavior — these can signal venting or burner issues that require qualified service.

Generator Rules — High-Risk Prevention

Portable generators produce large amounts of CO and are a leading cause of fatal poisonings during emergencies. Use generators outdoors only, at least 20 feet from the house, and never in a garage — even with the door open. If power is out, prioritize generator placement as seriously as fire safety.

Position the generator at least 20 feet from any building, with the exhaust directed away from doors, windows, and ventilation intakes. Even in heavy rain, do not move the generator closer to the house or under a covered patio — use a canopy or tent-like cover designed for generators instead. Before starting the generator, double-check that no windows or doors on the nearest side of the building are open. Generator carbon monoxide safety is one of the most important things to get right during an outage.

Garage and Vehicle Exhaust

Vehicle exhaust can rapidly build up CO in an attached garage and enter living spaces. Never warm up or idle a car in a garage. If your garage shares a wall with your home, treat it as a high-risk area for exhaust infiltration.

Even a few minutes of idling in an attached garage can produce dangerous CO levels. People sometimes underestimate how quickly exhaust builds up — even with the garage door fully open, exhaust can still enter living spaces through the connecting door, wall gaps, or shared ductwork. If you need to warm up a car, back it out of the garage first, then let it idle in the open driveway. Home carbon monoxide safety starts with treating an attached garage as a no-idle zone.

Travel, Rentals, Hotels

CO incidents can occur in rentals and hotels, especially in older buildings or where fuel-burning appliances are present. On arrival, locate CO alarms and confirm they are present. If an alarm sounds or you suspect exposure, leave immediately and contact staff and emergency services.

Winter and Storm Outages

Winter and storm seasons increase risk because heating runs longer and generators are used more often. Plan ahead: keep CO alarms working, know safe generator placement, avoid improvised indoor use of fuel-burning devices, and understand space heater safety.

When the power goes out during a cold spell, people reach for portable generators and alternative heating — and that's when CO incidents spike. Generators moved into garages "just for a minute," propane heaters used in sealed rooms, charcoal grills brought indoors — each of these scenarios repeats in emergency rooms every winter.

A pre-storm checklist can help you avoid last-minute decisions that put your household at risk:

• Test CO alarms and replace batteries before storm season.
• Identify where you will place a generator (outdoors, 20+ feet from the building, exhaust away from openings) — plan this before the outage happens.
• Stock flashlights and battery-powered lighting so you're less tempted to use fuel-burning devices indoors.
• Know which heating alternatives are safe for indoor use (electric battery-powered heaters) and which are not (propane camp heaters, charcoal, grills).
• If you don't have a generator, have a plan for staying warm that doesn't involve combustion indoors — extra blankets, warm clothing layers, or relocating to a shelter.

Before heating season, schedule a professional inspection of your furnace, water heater, and chimney. Many home carbon monoxide safety problems begin with equipment that worked fine last year but developed a crack or blockage over the summer.

Sources & References

• US CPSC — Carbon Monoxide Information Center
• CDC — Carbon Monoxide Poisoning
• NFPA — Carbon Monoxide Safety
• US CPSC — Generator Safety
• American Red Cross — Carbon Monoxide Prevention

Last updated: February 15, 2026