Re: Re: CULT: treated lumber information sources

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linda Mann wrote:
> 
> Thanks Dallas - any chance of summarizing what you know from these sites
> in a short post?  Just from the titles, it sounds as though arsenic
> contamination is the thing most are concerned about & some say it's a
> problem, others not.  True?
> 
> Having gotten the heebie jeebies after finding out the horrors of
> pentachlorophenol treated wood AFTER I'd already home treated a bunch of
> lumber years ago, before researchers realized all the problems with the
> stuff, I would like to be a little bit better informed 'next' time.
> 
> Linda Mann east Tennessee USA

Treated Lumber
The expert opinions expressed on these Web sites regarding treated
lumber and its use in the home and garden appear to support any position
pro and con you could care to name.

CCA (Chromium Copper Arsenate) Treated Wood Products
The wood preservatives industry claims that fears about CCA-treated wood
products are unfounded when the products are used properly. They also
claim that the products are extensively tested and approved by the
Federal government and other regulators. They fail to disclose that
their lobbyists have caused the CCA-treated wood products to be excluded
from the same regulatory controls required for other pesticide and/or
preservatives products. They also do not reveal the limitations of the
testing of their products and their influence upon the conduct of such
tests.

The universities and agricultural extension offices report that there
are some serious problems with CCA-treated products when handling,
sawing, burning and using the products in direct contact. They are also
concerned with the dangers of heavy metal contamination in the solid
waste stream when the time comes for disposal of these products.
However, they generally seem to think that the CCA-treated products are
relatively safe for use as construction material in the garden, if
certain basic precautions are used in their placement and handling.
Never use the sawdust in the garden. Never burn the treated wood or use
the burned ash in the garden. Keep certain types of plants away from
direct or near contact with landscaping timbers. In other words, some of
the academic authorities are saying that CCA-treated wood products are
potentially hazardous when used improperly, but they believe that their
testing shows there is only a limited amount of leaching of the
hazardous chromium, copper, and arsenic components in the garden; and
the leached products pose only limited hazards to the plants or the
human consumption of the plants.

Organic gardening publications, some agricultural and forestry
scientists, and other authorities find that CCA-treated products are
hazardous to use and handle, use in the garden, and dispose in the solid
waste stream. They find that the CCA-treated wood products leach the
heavy metal toxins in much greater quantity and in a much shorter time
span than admitted by the industry, governmental authorities, and
certain academic authorities with closer relationships to the industry.
They criticize the industry and academic testing programs, saying that
the testing is too limited to represent actual conditions of usage.
Manufacturers do not conform to the standards used for products in the
tests. They believe the tests did not reproduce the conditions found in
the gardens. They find that such products can damage plants and pose a
health hazard to humans working in the contaminated soil. The human
consumption of plants grown in the soil contaminated by such CCA-treated
products may or may not pose a health hazard, depending on the type of
plant consumed and the many variables concerning the contamination and
preparation of the plants to be eaten.

Penta
Penta, pentachlorophenol, is generally regarded as a hazardous material,
which lacks any justification for use in the garden or household under
any circumstances. It is reported that Penta will severely damage plants
when used in landscaping timbers. Authorities warn that Penta must never
be used inside of greenhouses. It is presently a restricted use chemical
due to its hazardous nature.

Creosote
The controversy over creosote treated wood products are not nearly so
disputed as they are for the CCA-treated wood products. All of the
authorities agree that creosote is toxic stuff. They only disagree about
how bad it is for use in the garden and in the natural environments.
Creosote is a hydrocarbon residue generally extracted from coal. All
such coal and petroleum based aromatic hydrocarbons are known to be
toxic and harmful carcinogens and mutagens. The dispute centers on just
how much these harmful and aromatic hydrocarbons leach into the soil and
vaporise into the air, and what the consequences may be for any
particular amount of exposure. Some authorities report that plant roots
do not take up the creosote leaching products. However, the aromatic
nature of creosote will damage nearby plants. More conservative
authorities are concerned about the long-term effects of exposure and
soil contamination. The previous links provide some good commonsense
guides about what exposures in the garden may or may not be acceptable
to plants and to humans. Creosote and its toxic dangers are persistent
in the environment just as any toxic oil spill is in contaminated soil.
It can be neutralized only by burning in high temperature incinerators.
Weathering cannot and does not volatize and reduce the toxicity of the
wood or the underlying contaminated soil to any extent that would
prevent harmful toxic exposures to humans, animals, and plants. Only
high temperature incineration reduces the carcinogenic and mutagenic
compounds to lesser and more benign compounds. Creosote is presently a
restricted use pesticide due to its toxicity.

Alternative Presevatives
There are some new wood preservatives which are advertised as being
environmentally safe. They are a more expensive substitute for the
CCA-treated wood products. These types of products are regarded as being
safe, because the preservatives are not known to be toxic to biological
organisms. ACQ (Ammoniacial Copper Quaternary), copper azole and/or
copper citrate, is one of these newer products.

Summary
The degree to which it is safe to use any given wood preservative
product is disputed among the authorities. Some products appear to be
safer to use than other products in some circumstances. Almost all of
the products are toxic to some greater or lesser extent. The one
sure-fire safeguard is to not use toxic wood preservatives in the
garden, regardless of the degree to which they may be hazardous or
non-hazardous. Minimizing your lifetime cumulative exposure to toxic
carcinogens and mutagens in air, water, adhesives, solvents, paints,
preservatives, herbicides, insecticides, and chemical fertilizers can
only reduce the risk of a multitude of presently unrecognized chemically
induced diseases. Trying to deduce where the borderline is between a
product which is hazardous or non-hazardous may prove to be futile and
an unnecessary gamble with the health of yourself, your family, your
animals, and your plants. Avoidance is the best policy, and a
conservative approach to usage may make the most commonsense compromise.
In any case, see the links in the earlier article for details and more
links about using treated wood products in the home and garden.

Dallas Patterson
nye@fidalgo
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