Chimney Fires: Causes, Prevention, and Emergency Response

Now that we have officially entered autumn, and the weather is turning cooler, a lot of us will begin using our fireplaces again. Before you light that first fire, the Livermore Firefighters would like to remind you to have your fireplace and chimney cleaned and inspected. 

Chimney fires are one of the most dangerous and often overlooked fire hazards in homes that use fireplaces or wood stoves. These fires can erupt suddenly, causing extensive damage and posing serious risks to life and property. In the Livermore area, sparks from burning creosote can ignite outside vegetation and start a wildfire. Understanding their causes, how to prevent them, and what to do in case of an emergency is essential for every homeowner.

Chimney fires are typically caused by the ignition of creosote - a highly flammable substance that builds up inside chimney walls. Creosote forms when wood burns incompletely, especially in low-temperature fires. Thick layers of creosote can ignite with just a spark. Burning unseasoned wet or green wood produces more smoke and creosote. Inadequate ventilation leads to cooler fires and more creosote. Improperly designed chimneys or poorly insulated flues can trap residue. Skipping annual inspections or cleanings increases risk.

Prevention is all about reducing creosote and maintaining a safe burning environment. Some preventive steps to take include:

• Schedule annual inspections: Hire a certified chimney sweep to inspect and clean your chimney.
• Burn only seasoned wood: Dry wood burns hotter and cleaner.
• Avoid slow, smoldering fires: Hotter fires reduce creosote formation.
• Install a chimney cap with a spark arrestor: Keeps out debris, animals, and moisture.
• Monitor your burn habits: Don’t overload the firebox or close the damper too early.

Chimney fires can be dramatic or silent. Some are explosive and obvious, while others smolder quietly. The fire may stay contained within the fireplace and chimney, or it could spread to the structure. 

Some warning signs to be alert for include:

• Loud cracking or popping noises
• Dense smoke or flames shooting from the chimney
• Intense, hot smell
• Vibrations or rumbling sounds
• Soot flakes or creosote chunks falling into the fireplace

If you suspect a chimney fire, act quickly but safely.

• Call 911 immediately, even if you think the fire is out. The fire department can check your roof and attic, as well as outside for any escaped brands.
• We generally don’t recommend trying to fight the fire yourself, but discharging a dry chemical extinguisher from the fireplace into the chimney may help. There are also commercial extinguishers specifically for chimney fires, like Chimfex.
• Avoid using water. Pouring water on a chimney fire can cause steam explosions or damage the flue.
• Close the damper after you have attempted any fire suppression. This may help cut off oxygen from the fire.
• Get everyone out of the house. 
• Do not use the fireplace again until it’s inspected and cleared by a professional. Even if the fire seems minor, it can cause hidden damage, which, if not fixed, could cause a structure fire next time it is used.

Chimney fires are preventable with proper care and attention. By understanding the risks and taking proactive steps, you can enjoy the warmth of your fireplace without worry. Make chimney safety part of your home maintenance routine—it’s a small effort that can prevent extensive damage.