Candles can produce carbon monoxide in very small amounts, but under normal use in well-ventilated areas, they do not pose a significant risk of carbon monoxide poisoning; however, burning multiple candles in a confined space may increase the risk.
Many people enjoy the warm glow and soothing scents of candles, but concerns about carbon monoxide (CO) emissions often arise. While candles do produce trace amounts of CO, the risk of poisoning is minimal in well-ventilated spaces. However, understanding the factors that influence CO buildup can help you use candles safely.
Do Candles Produce Carbon Monoxide?
Yes, burning candles releases small amounts of carbon monoxide as a byproduct of combustion. The wax (whether paraffin, soy, or beeswax) reacts with oxygen to produce heat, light, water vapor, carbon dioxide, and carbon monoxide. However, the quantity generated is significantly lower than what’s produced by fuel-burning appliances like propane heaters or gas stoves.
Factors Affecting CO Production
- Wax Type: Paraffin candles may produce slightly more CO than natural wax alternatives
- Wick Material: Lead-core wicks (now banned in many countries) produced more pollutants
- Burn Quality: Incomplete combustion from drafts or improper wick trimming increases CO
- Quantity: Burning multiple candles simultaneously raises CO concentration
Risk Levels of Candle-Related CO Poisoning
The risk of significant CO buildup from candles alone is extremely low in normal circumstances. According to research:
| Source | CO Production Rate | Comparison |
|---|---|---|
| Single candle | 0.01-0.05 ppm/hour | Negligible in ventilated space |
| Gas oven | 5-15 ppm/hour | Potentially dangerous |
| OSHA limit | 50 ppm (8-hour exposure) | Safety threshold |
For context, you would need to burn dozens of candles simultaneously in a tiny, sealed room to approach dangerous CO levels. This differs significantly from gas heating systems which can produce lethal CO concentrations quickly if malfunctioning.
Safety Precautions When Burning Candles
Ventilation Is Key
Always maintain airflow when burning candles. Open windows slightly or ensure the room has adequate air exchange. Avoid burning candles in small, airtight spaces like walk-in closets or tiny bathrooms without ventilation.
Smart Placement Matters
- Keep candles away from drafts that cause uneven burning
- Place on stable, heat-resistant surfaces
- Maintain 12-inch clearance from combustibles
Monitoring and Maintenance
Consider these additional safety measures:
- Install CO detectors (required by law in many areas for fuel-burning appliances)
- Trim wicks to 1/4 inch before each use to ensure clean burning
- Limit burn time to 4 hours maximum per session
- Never leave burning candles unattended
Recognizing Carbon Monoxide Poisoning
While candle-related CO poisoning is rare, symptoms to watch for include:
- Headache
- Dizziness
- Nausea
- Confusion
- Shortness of breath
If multiple people or pets in the same area experience these symptoms simultaneously, seek fresh air immediately and call emergency services. The CDC provides comprehensive guidance on CO poisoning recognition and response.
Alternative Lighting Options
For those concerned about indoor air quality:
- Battery-operated LED candles provide flickering light without combustion
- Electric wax warmers melt wax without flame
- Solar-powered lights offer ambient lighting
These eliminate CO concerns while still creating atmosphere. For heating alternatives, consider oil-filled radiators which don’t produce combustion byproducts.
Special Considerations
Sleeping With Candles Burning
Never leave candles burning unattended, especially overnight. Beyond CO concerns, this poses significant fire risk. The National Fire Protection Association reports candles cause approximately 7,400 home fires annually.
Candle Use in Power Outages
During emergencies when candles might be used for extended periods:
- Rotate candle use between different rooms
- Take regular breaks in fresh air
- Monitor all occupants for symptoms
- Consider battery-powered alternatives as primary light sources
For more on safe heating during outages, see Red Cross power outage safety tips.
