Consumer confidence in the
convenience and safety of today's home heating systems is usually
well-placed. The oil and gas heating industries have achieved
impressive safety records. Nonetheless, according to the U.S.
Consumer Product Safety Commission, over 200 people across the
nation are known to die each year from carbon monoxide poisoning
caused by problems in the venting - out of their homes - of toxic
gases produced by their heating systems. Other estimates for total
accidental CO poisoning are much higher. The Journal of the American
Medical Association, (JAMA Volume 261, No.8, February 24,1989)
estimates 1,600 deaths occur yearly.
In addition, around 10,000 cases of
carbon monoxide-related injuries are diagnosed each year. Because
the symptoms of prolonged, low-level carbon monoxide poisoning mimic
the symptoms of common winter ailments (headaches, flue, nausea,
dizziness, fatigue, even seasonal depression), many cases are not
detected until permanent, subtle damage to the brain, heart and
other organs and tissues has occurred. The difficulty of diagnosis
also means the numbers of people affected may be even higher.
WHAT IS CARBON MONOXIDE?
we all know that carbon monoxide is a very dangerous, colorless,
odorless gas, generally associated with your home heating system,
but for a little better understanding, let's take a quick trip back
to high school chemistry class. The gas or oil you burn for home
heating are compounds known as hydrocarbons (hydrogen + carbon). In
your furnace these hydrocarbons are mixed with oxygen from the air
in your home, and burned to produce heat.. When your furnace and
chimney are working properly, the gas or oil is burned more or less
completely, and the resulting fumes are mainly carbon dioxide
(carbon + 2 oxygen atoms) and water vapor. If your furnace doesn't
get enough oxygen, either because the house is too tight or the
chimney isn't functioning properly, carbon monoxide (carbon +1
oxygen atom) is produced instead. It's the lack of that one little
oxygen atom that causes all the trouble.
WHAT CARBON MONOXIDE DOES TO YOU
Too much carbon monoxide in your blood
will kill you. Most of us know to try to avoid this. Less well known
is the fact that low-level exposure to this gas also endangers your
One of the imperfections of our human
bodies is that, given a choice between carbon monoxide and oxygen,
the protein hemoglobin in our blood will always latch on to carbon
monoxide and ignore the life-giving oxygen. Because of this natural
chemical affinity, our bodies - in effect - replace oxygen with
carbon monoxide in our bloodstream, causing greater or lesser levels
of cell suffocation depending on the intensity and duration of
The side-effects that can result from
this low-level exposure include permanent organ and brain damage.
Infants and the elderly are more susceptible than healthy adults, as
are those with anemia or heart disease.
The symptoms of low-level carbon
monoxide poisoning are so easily mistaken for those of the common
cold, flu or exhaustion that proper diagnosis can be delayed.
Because of this, be sure to see your physician about persistent,
flu-like symptoms, chronic fatigue or generalized depression.
IF YOU SUSPECT A PROBLEM
If you ever suspect a carbon monoxide
problem, immediately open doors or windows to ventilate the house
and get everyone outside for fresh air. Most utility companies will
respond to emergency calls and check your house and heating system
for the presence of carbon monoxide. Do NOT reinhabit the house
until you are certain there is no longer a problem. If necessary
seek medical attention, treatment is very important. Have the
heating system and the chimney checked and serviced by reputable
professionals as soon as possible.
WHY IS POISONING FROM CARBON MONOXIDE ON THE
1) Today's houses are more air
tight due to energy conserving measures. Consequently there is less
fresh air coming into a home and not as many pathways for stale or
polluted air to leave it. When furnaces and boilers are starved of
the oxygen needed to burn fuels completely, carbon monoxide is
produced. Many newer houses are so airtight that powered exhaust
fans in the kitchen and bathroom can overcome the draft in the
furnace chimney and literally pull the toxic gases into the living
2) The new high-efficiency gas and
oil furnaces, when hooked up to existing flues, often do not perform
at an optimum level. The differences in performance create
conditions that allow combustion byproducts to more easily enter
home living spaces.
3) The above conditions join a
number of older, on-going problems including damaged or
deteriorating flue liners, soot build-up, debris clogging the
passageway, and animal or bird nests obstructing chimney flues.
MAINTENANCE IS IMPORTANT
When gas and oil burn in vented heating
systems, the dangerous fumes that are the by-products of combustion
- including carbon monoxide - are released into the chimney through
a connector pipe. Funneling these fumes out of the living area is
the primary purpose of a chimney. In addition to carrying off toxic
gases, chimneys also create the draft (flow of air) that provides
the proper air and fuel mixture for efficient operation of the
heating appliance. Unfortunately, many chimneys in daily use in
homes throughout the country either are improperly sized or have
conditions that make them unable to perform their intended function.
Natural gas is a clean-burning fuel, but
today's high-efficiency gas furnaces pose special problems. (see the
pages on GAS for a more complete discussion) The fumes they produce
are cooler and contain high levels of water vapor, which cause more
condensation than older models. Since these vapors also contain
chlorides picked up from house-supplied combustion air, the flues
are subjected to more corrosive conditions than before and can
quickly deteriorate or plug up completely.
Oil flues need to be cleaned and
inspected annually because deposits of soot may build up on the
interior walls of the chimney. The amount of soot depends on how
well tuned the furnace is and whether the house provides sufficient
air for combustion. Excessive soot causes problems ranging from
inefficient furnace operation to completely blocked chimneys.
To the extent that problems with either
of these heating systems interfere with the flow of toxic gases and
particles out of the house, they may also force carbon monoxide into
the home. They may cause a one-time, high-level exposure situation
or release smaller amounts more regularly over a longer period.
These problems should never be ignored.
In the United States, numerous agencies
and organizations now recognize the importance of annual heating
system inspection and maintenance in preventing carbon monoxide
poisoning. The U.S. Consumer Product Safety Commission, the U.S.
Environmental Protection Agency, the National Fire Protection
Association, the American Lung Association - are some of the
organizations that now encourage the regular maintenance of home
heating systems and their chimneys in order to keep "the silent
killer" at bay.
A well tuned furnace or boiler,
connected to a venting system or flue that is correctly sized,
structurally sound, clean and free of blockages, will operate
efficiently and produce a warm and comfortable home. Carbon monoxide
detectors are now readily available and no home should be without at
least two, one near the furnace and one near the sleeping area of
the home. Detectors are NOT a substitute for routine maintenance,
but can be a lifesaver should problems occur.
Considering the risks involved when gas
or oil systems are neglected, and the benefits that accrue when they
are properly maintained, we suggest you have your furnace serviced
yearly by a qualified technician and your chimneys checked annually
by a Professional Chimney Sweep and cleaned or repaired as