In 1982, wood-burning appliances accounted for more fires, more
fire deaths, and greater property damage than any other kind of
heating fuel -- about 140,000 fires, 250 deaths and $257 million
in property damage. These losses represented 20 percent of all
residential fires in the U.S., 5 percent of all fire deaths, and
8 percent of estimated property damage.
CPSC research indicates that most wood heating fires involve the
chimney and not the appliance itself. The majority of these
fires are contained within the chimney and cause no damage to
the house. The Commission is concerned, however, not only about
the chimney fires that did ignite other parts of the house, but
also about the potential future hazard from the continued use of
chimneys whose structural integrity has been compromised by a
chimney fire. This is especially true in light of the fact that
many contained chimney fires are not reported to the fire
services; in fact, consumers may not even be aware that a
chimney fire has occurred.
Therefore, the Consumer Product Safety Commission is issuing a
special safety alert concerning chimneys used with wood burning
stoves, fireplaces, and fireplace inserts. The Commission
urgently warns consumers to be aware of the potential fire
hazards associated with these chimneys.
Now that the nation has entered the heating season, the
Commission strongly urges you, if you have a stove or fireplace,
to check the chimney for any damage that may have occurred in
the past heating season. If it is difficult to examine the
chimney, a local chimney repairman, chimney "sweep," or dealer
can help. Have any damage repaired NOW.
Most fires involving either masonry or
prefabricated metal chimneys occur because of improper
installation, use or maintenance. The Commission staff has
identified the following common causes of fires:
Improper chimney installation too close to wood framing.
Installation of thermal insulation too close to the chimney.
Improperly passing the stovepipe or chimney through a
ceiling or wall, causing ignition of wood framing.
Structural damage to the chimney caused by the ignition of
creosote (a black tar-like substance that builds up inside
the chimney in normal use).
Structural damage to metal prefabricated chimneys
that results in wood framing being exposed to excessive
temperatures or leakage of potentially toxic gases to the
interior of the home can take the following forms:
Corrosion or rusting of the inner liners of metal chimneys.
Buckling, separation of the seam, or collapsing of the inner
liner of metal chimneys. (This can result from too hot a
fire, especially in high-efficiency stoves and in fireplace
inserts, or from a creosote fire.)
Structural damage also occurs in masonry chimneys, often
associated with deterioration or improper installation of the
chimney. The tile inner liner and the surrounding brick or block
structure may crack and separate, perhaps as a result of the
ignition of creosote that has built up in the chimney. Many old
chimneys do not have a tile liner. If your chimney does not have
a liner, the addition of a properly installed liner is
advisable. Also, a clay liner should be sealed with refractory
Even when the heating appliance is properly installed, people
with either metal or masonry chimney systems should frequently
check the chimney for creosote deposits, soot build-up, or
physical damage. This involves only a simple visual examination,
but it should be done as often as twice a month during heavy
use. If you see heavy creosote buildup, suspect a problem, or
have had a chimney fire, a qualified chimney repairman or
chimney "sweep" should perform a complete safety inspection.
They can arrange for any necessary repairs or creosote removal,
which must be done before the heating appliance is used again.
There are products now available which, according
to recent tests conducted by independent laboratories, show
promise for reducing the production of creosote and harmful
pollutant emissions. Advance wood stove designs appear to
provide more complete combustion of the fuel. Catalytic
combustors appear to achieve similar results, and are available
with new stoves or as separate components which can be installed
between the flue gas exit and the chimney connector of existing
The Commission advises owners of all chimneys to:
Be sure that the chimney and stovepipe were installed
correctly in accordance with the manufacturer's
recommendations and local codes. If there is any doubt, a
building inspector or fire official can determine whether
the system is properly installed.
Minimize creosote formation by using proper stove size and
avoiding using low damper settings for extended periods of
Have the chimney checked and cleaned routinely by a chimney
"sweep" at least once a year. Inspect it frequently, as
often as twice a month if necessary, and clean when a
creosote buildup is noted.
Always operate your appliance within the manufacturer's
recommended temperature limits. Too low a temperature
increases creosote buildup, and too high a temperature may
eventually cause damage to the chimney and result in a fire.
Frequently look for signs of structural failure.
If you have had a fire or other safety problem
with your chimney, or would like additional information, call
the Commission's toll-free Hotline 800-638-CPSC