Chimney Fire Extinguishers and Suppression Sticks: What They Do

What the product actually is

The item sold as a chimney fire extinguisher looks more like a road flare than the red cylinder hanging in a kitchen. It has a striker cap and a body packed with a chemical mix. Once lit and placed in the firebox, it burns hard and produces a dense cloud of gas and fine particles. That cloud rides the draft up the flue, the same path the smoke takes, and fills it.

Fire needs fuel, heat and oxygen. Inside a burning chimney, the fuel is creosote stuck to the walls, and nobody can reach it. What the stick changes is the oxygen. By filling the flue with gas that does not support combustion, it chokes the fire along the creosote layer. Some products are designed to be dropped onto the burning logs, others into the firebox beside them; the package spells out which.

Where these products fit in a real chimney fire

The signs are hard to miss: a roar like a train or a jet, loud popping, thick dark smoke and sometimes flames or sparks shooting from the top. It can move fast. The first priority is people. Everyone leaves, pets included, and someone calls 911 from outside.

A suppression stick fits into the few seconds before you leave, and only if it is right next to the fireplace and the instructions are already familiar. Lighting it, closing the glass doors or the stove door and walking out is very different from standing in a smoky room reading a label. If it takes more than a moment, skip it and go.

• Get everyone out of the house, then call 911
• On the way out, if quick: use the stick per its label, close the stove door or fireplace glass
• Do not pour water down the flue or onto a hot stove
• Do not go on the roof
• Let firefighters check the attic, walls and roof before anyone goes back in

Why closing off the air matters

Suppression products rely on the gas staying in the flue long enough to do its job. With a wood stove, that is easy: shut the door, close the air controls, and the gas moves up the pipe with very little fresh air following it. With an open masonry fireplace, room air keeps pouring into the opening and up the flue, diluting the gas. Glass doors help. A wide-open fireplace with no doors gives the product a much harder job.

That is also why the same advice shows up whether or not a stick is used: cut the fire's air. Closing a stove's air intake or a fireplace's glass doors slows a chimney fire on its own, and costs you only a second on the way out.

Suppression stick or regular extinguisher

A standard household extinguisher is aimed at a fire you can see: a log that rolled onto the hearth, a rug that caught an ember, a towel too close to the stove. Spraying it into the firebox does very little to a fire burning thirty feet up inside the flue, and the discharge spreads powder through the room. Both have a place near a wood-burning appliance, for different problems.

The EPA's wood-burning guidance recommends keeping a fire extinguisher handy wherever wood is burned. Pair it with working smoke and carbon monoxide alarms and a plan for getting everyone out.

What a suppression stick cannot do

If heat has already passed through cracked tiles into the brick and framing, or embers have landed on the roof, nothing in the firebox will reach them. Chimney fires can smolder in hidden spaces next to the chimney long after the roaring stops, which is why the fire department checks the attic and walls with their own equipment.

These products also cannot tell you whether the chimney survived. A clay liner that has just been through a chimney fire may be cracked from top to bottom while looking fine from the fireplace. Flue tiles in older brownstones and row houses are often original, and a fire can be what finally opens the joints that years of freeze-thaw cycles weakened.

Choosing and storing one

If you burn wood regularly, keeping a suppression stick near the stove or fireplace is reasonable. Read the label when you buy it, not during a fire, and check that it is meant for the type of appliance you have. Store it where it stays dry, within reach of the hearth but not so close it gets hot. Products have a shelf life; the package shows how to tell when it is due for replacement.

Teach everyone who lights fires in the house where it is and how it works, and make sure they also know that leaving and calling for help comes first.

Gas, pellet and oil appliances

Suppression sticks are sold for wood-burning fireplaces, stoves and inserts, where creosote is the fuel. A gas fireplace, a pellet stove or an oil boiler has its own failure modes and its own manual, and the manual is the place to look for what to do if something goes wrong. For any fire you cannot immediately control, the answer is the same: leave and call 911, or the gas utility if you smell gas.

Heating flues have a version of the chimney fire problem too. An oil boiler that has been sooting up can pack its flue base and connector with soot, and a puff-back or a hot misfire can ignite it. The cure there is a tuned burner and a cleaned flue, not a product kept by the boiler.

After a chimney fire, even a short one

NFPA 211 calls for a chimney to be inspected after a chimney fire or any other event that may have damaged it. That applies whether firefighters put it out, a suppression stick did, or it burned out on its own. Signs a sweep looks for include puffed, honeycomb-like creosote, cracked or displaced flue tiles, warped damper and cap metal, discolored roofing near the chimney and heat damage to nearby framing.

If you plan to file an insurance claim, take photos and talk to your insurer before anything is cleaned up. Do not light another fire until the chimney has been inspected, swept and any damage repaired. When you need that inspection, our licensed and insured crew can document what the fire did and lay out the repair in writing.