CHLORINE BLEACH IS
NOT EFFECTIVE IN KILLING MOLD
For These Reasons:
(1) The object to killing mold
is to kill mold at its "roots".
Mold remediation involves the need to disinfect wood
and wood-based building materials, all of which are
porous materials. Thus, chlorine bleach
should not be used in mold remediation
as confirmed by OSHA's Mold Remediation/ Clean Up
Methods guidelines. The use of bleach as a mold
disinfectant is best left to kitchen and bathroom
countertops, tubs and shower glass, etc. (What
is Mold?, About Mold, Mold Facts)
Bleach does kill bacteria and kill viruses, but has
not been proven effective in killing molds on
non-porous surfaces. Bleach itself is 99%
water. Water is one of the main contributors
of the growth of harmful bacteria and mold.
Current situations using bleach re-grew and
regenerated mold and bacteria twice the CFU counts
than were originally found before bleaching, within
a short period of time. Bleach is an old method used
for some bacteria and mold. It is the only product
people have known for years. The strains now
associated within Indoor Air quality issues are
resistant to the methods our grandmothers employed
to clean-up mold.
potential mold 'killing' power chlorine
bleach might have, is diminished significantly as
the bleach sits in warehouses, on grocery store
shelves or inside your home or business 50% loss in
killing power in just the first 90 days inside a
never opened jug or container. Chlorine constantly
escapes through the plastic walls of its containers.
(4) The ionic
structure of bleach prevents Chlorine from
penetrating into porous materials such as drywall
and wood---it just stays on the outside surface,
whereas mold has enzyme roots growing inside the
porous construction materials---however, the water
content penetrates and actually FEEDS the
mold---this is why a few days later you will notice
darker, more concentrated mold growing (faster) on
the bleached area.
Bleach accelerates the deterioration of materials
and wears down the fibers of porous materials.
Bleach is NOT registered with the EPA as a
disinfectant to kill mold. You can verify this
important fact for yourself when you are unable to
find an EPA registration number for killing mold on
the label of any brand of chlorine bleach.
bleach off gases for a period of time. Chlorine off
gassing can be harmful to humans and animals. It has
been known to cause pulmonary embolisms in low
resistant, and susceptible people.
bleach will evaporate within a short period of time.
If the area is not dry when the bleach evaporates,
or moisture is still in the contaminated area
(humidity, outside air dampness), you could re-
start the contamination process immediately and to a
(9) Chlorine is
a key component of DIOXIN. One of the earliest
findings of dioxin's toxicity in animals was that it
caused birth defects in mice at very low levels.
This finding led to dioxin being characterized as
"one of the most potent teratogenic environmental
agents". The first evidence that dioxin causes
cancer came from several animal studies completed in
the late 1970's. The most important of these,
published in 1978 by a team of scientists from Dow
Chemical Company, led by Richard Kociba, found liver
cancer in rats exposed to very low levels of dioxin.
This study helped establish dioxin as one of the
most potent animal carcinogens ever tested and,
together with the finding of birth defects in mice,
led to the general statement that dioxin is the
"most toxic synthetic chemical known to man."
Opposing Views and Confusion.
Chlorine bleach, commonly referred to as laundry
bleach, is generally perceived to be an "accepted
and answer-all" biocide to abate mold in the
remediation processes. Well-intentioned
recommendations of the Environmental Protection
Agency (EPA) and other federal, state and local
agencies are perpetuating that belief. And confusing
the issue is one federal agency, the Occupational
Health and Safety Administration (OSHA), taking an
opposing point of view by NOT recommending the use
of chlorine bleach as a routine practice in mold
Bleach Really Kill Mold?
Will chlorine bleach kill mold or not—yes or no? The
answer is yes, but with a caveat. That answer comes
from The Clorox Company, Oakland CA, manufacturer
and distributor of Ultra Clorox® Regular Bleach. The
company's correspondence to Spore°Tech Mold
Investigations, LLC stated that their Tech
Center studies supported by independent laboratories
show that "…3/4 cup of Clorox liquid bleach per
gallon of water will be effective on hard,
non-porous surfaces against… Aspergillus niger and
Trichophyton mentagrophytes (Athlete's Foot
Fungus)". Whether or not chlorine bleach kills
other molds and fungi, the company did not say. The
words "hard, non-porous" surfaces"
present the caveat. Mold remediation
involves the need to disinfect wood and wood-based
building materials, all of which are porous
materials. Thus, chlorine bleach should not be used
in mold remediation as confirmed by OSHA's Mold
Remediation/ Clean Up Methods guidelines. The use of
bleach as a mold disinfectant is best left to
kitchen and bathroom countertops, tubs and shower
Chlorine Bleach is NOT Recommended for Mold
Chlorine bleach (sodium hypochlorite) is corrosive
and that fact is stated on the product label. Yet
the properties of chlorine bleach prevent it from
"soaking into" wood-based building materials to get
at the deeply embedded mycilia (roots) of mold. The
object to killing mold is to kill its
"roots". Reputable mold
remediation contractors use appropriate products
that effectively disinfect salvageable mold infected
wood products. Beware of any mold inspector or mold
remediation company that recommends or uses chlorine
bleach for mold clean up on wood-based building
Chlorine Bleach Is Active Ingredient in New Mold &
The appearance of new mold and mildew household
products on store shelves is on the rise. Most
are dilute solutions of laundry bleach.
The labels on these mold and mildew products state
that they are for use on (again) hard,
non-porous surfaces and not for wood-based
materials. Instructions where not to apply the
products are varied. A few examples where the
branded products should not be applied include wood
or painted surfaces, aluminum products, metal
(including stainless steel), faucets, marble,
natural stone, and, of course, carpeting, fabrics
and paper. One commercial mold and mildew
stain remover even specifically states it
should not be applied to porcelain or metal without
immediate rinsing with water and that the product
isn't recommended for use on formica or vinyl.
purchasing a mold and mildew product, read and fully
understand the advertised purpose of that product —
and correctly follow the use instructions of a
purchased product. The labeling claims on these new
products can be confusing — some say their product
is a mold and mildew remover while another
says their product is a mildew stain remover
and yet others make similar 'ambiguous'
claims. Make double sure that the product satisfies
your intended need on the surface to which it is to
be applied. If your intention is to kill mold, make
sure the product does exactly that and follow
the directions for usage. Consumers may find
that mixing their own diluted bleach solution will
achieve the same results as any of the new mold and
mildew products — keep in mind that the use
of chlorine bleach is not for use on mold infected
wood products including wall board, ceiling
tiles, wall studs, fabric, paper products, etc.
Laundry bleach is not an effective mold killing
agent for wood-based building materials and
NOT EFFECTIVE in the mold remediation process.
OSHA is the first federal agency to announce a
departure from the use of chlorine bleach in mold
remediation. In time, other federal agencies are
expected to follow OSHA's lead. The public
should be aware, however, that a chlorine bleach
solutionIS an effective sanitizing product
that kills mold on
hard surfaces and
neutralizes indoor mold allergens that trigger
WARNING: Never mix chlorine with ammonia products, as
the result is extremely toxic.
bleach can cause serious health problems.
fumes are very caustic and great care must be taken
not to breath it in too much.
also very damaging to clothing and carpeting, the
human body, and the environment.
mix chlorine with ammonia products, as the result is
impossible to completely eliminate airborne mold.
Specialists warn that living in environments
entirely safe from mold spores, bacteria or viruses
would not be healthy since our immunological system
needs to be active. It is recommended that steps be
taken to reduce airborne microorganisms, not
• Reduce humidity in your home by opening windows
for approximately 30 minutes daily;
• Prevent leaks due to rain; and when unavoidable,
dry and treat water damage within 24 to 48hours;
• Regularly clean places that accumulate humidity
such as showers, faucets and pipes and the floor
areas around such fixtures;
• Limit carpets and plants in your home;
• Use air purifier to drastically reduce high
• Whenever possible, leave objects exposed to
sunlight after cleaning. It is very important that
objects are dried after cleaning otherwise they will
be subject to new mold contamination.
• Porous materials such as wood, fabric, cushions,
and mattresses retain water and are likely to be
contaminated, making it difficult to clean them. In
the event that these objects are contaminated, it is
advised to dispose them.
Want more information on Indoor Air Quality?
Click On Links Below
Click here to see what the EPA has to say
about Mold in your home.
Environmental Protection Agency The Inside Story /
A Guide to Indoor Air Quality
Mold Resources Info Page
Apartment Owners guidelines for dealing with mold
A Brief Guide to Mold, Moisture, and Your Home
Introduction to Molds
Other PCO /