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CCA-Wood (Pressure Treated Wood) |
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What
is chromated copper arsenate (CCA)-treated wood?
Chromated copper arsenate-treated wood is often referred to
as pressure treated wood. CCA is a chemical wood preservative
that protects wood from damage by insects, mould, sun and water.
Chromium, copper and arsenic can leach out of CCA-treated wood.
Small amounts of these chemicals have been measured on wood
surfaces and in soil and ground cover near the wood.
The risk of illness from exposure to chemicals leaching from
CCA-treated wood is low. The following information has been
prepared to assist those who wish to minimize their exposure
to CCA-treated wood chemicals.
What is CCA-treated wood used for?
CCA-treated wood is commonly used for outdoor structures such as decks,
fences, picnic tables and play structures. It is also used for
landscaping. New pressure-treated wood has a greenish tint.
Since the green tint fades with time, it may be hard to tell
if an older wooden deck or play structure was made from CCA-treated
wood. Check with the builder. Manufacturers are now labelling
all new CCA-treated wood to indicate that it contains arsenic.
Is CCA-treated wood a health concern?
The risk of immediate illness from short-term exposure to chemicals
from CCA-treated wood is low. Although arsenic can be poisonous
at very high doses, the amounts measured on CCA-treated wood
are a thousand times less than a lethal dose. The other two
elements in CCA, copper and chromium, are relatively less toxic
to humans.
While small amounts of arsenic may not be harmful to health
in the short-term, it is best to avoid unnecessary exposure
because arsenic is a known human carcinogen.
It is not yet known whether long-term exposure to arsenic leaching
from CCA-treated wood is sufficient to increase the risk of
cancer or other health effects.
How are people exposed to arsenic from CCA-treated wood?
- People can be exposed to arsenic through residues present
on wood surfaces and from the soil or sand beneath structures
made of CCA-treated wood.
- Arsenic can be ingested through hand-to-mouth activity
after contact with wood surfaces and nearby soil that contains
arsenic leached from CCA-treated wood.
Who can be exposed?
- Young children (under 6 years of age) who play on CCA-treated
wood structures are likely to have the greatest exposure
because of their frequent hand-to-mouth activity. They are
also most likely to play for periods of time underneath
play structures where they could be exposed to arsenic in
the soil.
- People who spend considerable amount of time eating on
CCA-treated picnic tables, or playing on or working with
CCA-treated wood may also be exposed.
What precautions can I take to reduce exposure?
- Coat the structure with a penetrating oil-based wood-finishing
sealant to significantly reduce any leaching chemicals.
Re-apply sealant every one or two years, depending on wear
and weathering.
- Wash hands after contact with CCA-treated wood. This is
particularly important for young children, who tend to put
their hands in their mouths.
- Use a tablecloth when eating on a picnic table made of
CCA-treated wood.
- Fruit and vegetable garden boxes made of CCA-treated wood
should have a plastic lining on the base and sides of the
box to separate the wood from the soil.
- Never burn CCA-treated wood or use it as compost or mulch.
Burning CCA-treated wood is a serious health concern as
it releases harmful amounts of chemicals into the air and
the ash.
Are there alternatives to CCA-treated wood?
Consider avoiding CCA-treated wood to build structures for children.
Look for alternatives to CCA-treated wood such as cedar, redwood,
metal, and plastic. Consult your local hardware or building
store for wood treated with non-arsenic containing preservatives.
What should I do if I have an existing structure made of
CCA-treated wood?
If you have an existing structure (e.g. deck or playground equipment)
made of CCA-treated wood, it is not necessary to remove the
structure. To minimize exposure, use a penetrating oil-based
wood-finishing sealant on the structure. Re-apply sealant every
one or two years, depending on wear and weathering. This can
help reduce the amount of arsenic released by as much as 90%.
Consult your local hardware or building store for appropriate
products.
Elevated arsenic levels may exist in the soil or sand beneath
structures made of CCA-treated wood. If there is only bare soil or sand under the structure, consider the following:
- Fence or screen off areas underneath decks to prevent
access by children and pets.
- Plant a dense ground cover (e.g. grass) to provide a barrier
between the soil and human/animal contact.
- If exposed to soil or sand beneath the wood, remove shoes
or wipe feet before entering the house.
What's the City of Toronto doing in the City Parks?
Parks and Recreation tested arsenic levels in soil and on the wood surface at 217 parks and city-owned child care centres with CCA-treated wood play structures. Structures located at all child care centres had very low levels of arsenic (below any action level). Soil below the play structures at 31 parks was above federal guidelines for arsenic and requires replacement. As a precautionary measure, the remediation plan also recommended sealing the wood in these play structures as well as those in 26 other parks where tests indicated elevated levels of arsenic on the wood surface.
Sealing and soil replacement is taking place over the summer and fall of 2003.
Review the list of playgrounds under remediation (PDF file size 20.5KB)
Where can I get more information?
For more information contact:
Toronto Public Health, 416-338-7600
Health Canada - Pest Management Information Service,
(toll free 1-800-267-6315) Fact sheet on
Chromated Copper Arsenate (CCA) Treated Wood
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