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#784 - Late Lessons From Pressure-Treated Wood - Part 1, 04-Feb-2004

Published February 12, 2004

by Sandra Steingraber, Ph.D.*

Within the European Union, the European Environment Agency
(EEA) is charged with providing information for environmental
decision-making, especially in situations where the science is
uncertain. Three years ago, this agency published a remarkable
book, Late Lessons from Early Warnings: The Precautionary
Principle 1896-2000.[1]

This report explores how scientific knowledge about possible
environmental health threats is gathered and used to make
public decisions. Organized around twelve case studies --ranging from
radiation to mad cow disease -- the various
chapters benefit from hindsight as they examine the ways in
which the first warnings about these now-known hazards were
sometimes wisely heeded but more often foolishly ignored,
cynically scorned, or researched for decades until the evidence
for harm became so egregious that something had to be done. In
some cases, the actions finally taken to redress the problem
were so late in coming that "pipelines of unstoppable
consequences" were already set in place.

The earliest warnings on the dangers of asbestos, for example,
came from a British factory inspector, Lucy Deane, who, in
1898, correctly documented the "evil" effects of inhaling its
tiny, glass-like fibers. One hundred years later, the United
Kingdom finally banned white asbestos. The current death rate
in England from asbestos-related disease is 3,000 people per
year.[2] An early warning unheeded.

Last month in Brussels, I had the privilege of hearing David
Gee, the report's principle author, address the European
Parliament. Why, he asked, do so many environmental health
disasters fall victim to wait-and-see attitudes? What lessons
can be brought from the past to the problems of the present? In
an upcoming issue of Rachel's Environment & Health News, we
will look more closely at the warnings and lessons in Gee's
report (which is soon to be re-released with additional case
studies [3]) and how it is inspiring the implementation of the
precautionary principle in Europe.

Here, we apply Gee's historical approach to an environmental
health problem that continues to haunt back yards and
playgrounds throughout the United States: pressure-treated

The name itself is a euphemism. What pressure-treated wood is
actually treated with is a mixture of pesticides called
chromated copper arsenate (CCA). Pressure-treated lumber is
made by placing a freshly milled board inside a vacuum chamber
and sucking from its fibers all water and air. Then, under high
pressure, copper, chromium, and arsenic are forced into the now
empty cells.[4] Pressure treatment is to wood what embalming is
to humans.

As of January 1, 2004, after seventy years of production, the
manufacture of pressure-treated (CCA) wood for residential use
has ended in the United States.[5] It turns out that the
arsenic in pressure-treated wood rubs off on the hands of those
who touch it. When those who touch it are children, their risk
of developing lung and bladder cancer are significantly
raised.[6] Young children at play put their hands in their
mouth an average of 16 times an hour[7]. CCA is 22 percent pure
arsenic by weight. Arsenic is a known human carcinogen.[8]

A recall of all the swing sets, picnic tables, decks, and
fences already constructed from this lumber is, however, not
part of the decision to cancel the registration of CCA. And
with 90 percent of all outdoor wooden structures in the United
States made of pressure-treated wood, each with an expected
life span of twenty years or more, a "pipeline of unstoppable
consequences" may, even now, be well under construction.
Weathered lumber leaches as much -- or more -- arsenic than
newly milled boards.[10] Arsenic, like all metals, is
absolutely persistent in the environment. It does not
biodegrade. It does not go away.

Pressure-treated wood is a case study not included in the EEA's
"Late Lessons" report -- but it could be.

The story begins in 1933 when an Indian engineer, Sonti
Kamesam, made a discovery that saved the lives of countless
coal miners: injected into wood, arsenic and copper prevent
timber beams from rotting. Arsenic, a time-honored poison,
kills wood-eating insects. Copper kills fungus. Kamesam's
special trick was to add chromium to his formula, thereby
binding the two toxic metals to the wood fibers.[11] The result
was stronger roofs in the damp underground tunnels through
which coal is extracted. One can imagine that the last thing a
coal miner wants to see in the beams above his head is dry rot
or termites.

Kamesam's invention not only extended the life expectancy of
miners in India, it saved money and trees. His work quickly
attracted attention in the United States. A patent was granted
in 1938.[12] Meanwhile, researchers in Mississippi pounded
wooden stakes treated with copper chromium arsenate (CCA) into
fields that swarmed with termites. Months later, they were
still standing. In 1950, a highly impressed Bell Telephone
applied for permission to use CCA wood for telephone poles.[13]
At this time, arsenic was known to be an acute poison, but its
ability to cause cancer at low doses was not generally

For the next two decades, CCA wood remained a specialty
product. Porches, fences, docks, and boardwalks continued to be
constructed out of tree species that are naturally
rot-resistant, such as cedar, redwood, cypress, or fir. When
the structures from these woods finally collapsed -- or some
unlucky soul fell through the floorboards -- they were simply
rebuilt. Then, in the 1970s, the price of wood soared. Cheap,
plantation-grown southern pine became the homeowner's
construction material of choice.[14] And it could be made to
repel insects and dry rot with a pesticidal formulation
originally intended to prevent mines from caving in.

Early concerns about pressure-treated wood surfaced during the
1970s as pressure-treated wood found its way into picnic
tables, gazebos, landscaping timbers, and California-style
decks on the backs of suburban homes.[15] No one eats,
barbecues, or sunbathes on the pesticide-soaked rafters of mine
tunnels, but the back yard deck was specifically designed with
such activities in mind. Even more ominous was the growing use
of pressure-treated wood in children's playgrounds. Wooden,
castle-style play structures, complete with towers and swaying
suspension bridges, became the rage. In 1978, the U.S.
Environmental Protection Agency began a special review.

Ten years and many delays later, the EPA decided to reregister
CCA as a pesticide without restrictions on the use of the
treated wood -- in spite of the fact that CCA exceeded the
agency's risk criteria for carcinogenicity, and all other uses
for arsenical pesticides were canceled.[16] At this point,
almost no one in the general public was aware that
pressure-treated wood contained pesticides. Nor that those
sawing or sanding the wood should wear goggles and gloves. Nor
that work clothing that comes in contact with the wood should
be washed separately. Nor that food should never touch it.

The EPA did recommend that pressure-treated wood sold directly
to consumers via lumber yards and home improvement centers bear
warning labels. The timber industry balked, proposing instead
that retail stores should distribute fact sheets to educate
buyers about the wood's potential hazards. The government
agreed. Few retailers complied with this decision. The
government did little to enforce it.[17]

Warnings continued to trickle in throughout the 1980s. Workers
in wood treatment plants were found to have elevated levels of
arsenic in their urine. A government employee became completely
disabled after building picnic tables in an unventilated shop.
Eight members of a rural Wisconsin family fell ill with a
mysterious neurological disease that turned out to be arsenic
poisoning caused by burning pressure-treated lumber in the wood

In 1990, the Consumer Product Safety Commission released the
results of its investigation into children's exposure to CCA
from playing on pressure-treated wood playground equipment. The
study did conclude that contact with such play structures
increases children's exposure to arsenic, but the only health
endpoint considered was skin cancer and the risks were
considered insufficient for a ban.[19]

Then, in the 1990s, the scientific case against
pressure-treated wood became more damning. The National
Research Council reported that arsenic exposure through
drinking water was linked to lung and bladder cancers and could
exert its carcinogenic powers at much lower levels of exposure
than previously believed. Children, whose livers metabolize
arsenic more slowly, were shown to be at particular risk.[20]
Other discoveries followed: at very low levels, arsenic
interferes with a family of hormones called glucocorticoids,
possibly raising the risk for diabetes.[21]

Meanwhile, in 1996, far from the lab bench, a Connecticut
chemist, David Stilwell, began crawling around back yard decks
throughout New England. A year later, he reported that the soil
under and around pressure-treated structures contained
concentrations of arsenic far in excess of background levels,
and in some cases, far in excess of the clean-up standards for
Superfund sites. More than sixty years after Kamesam's
humanitarian invention, Stilwell discovered that chromium does
not serve as such an effective binding agent after all.
Eventually, the arsenic and copper leach out. Especially if the
wood is rained on.[22]

Still other researchers began to consider if inhalation of
arsenic-contaminated dust -- as when children play in the dirt
beneath decks and play structures -- might be a route of
exposure as significant as ingestion by hand-to-mouth

In light of these discoveries, two environmental organizations,
Environmental Working Group (EWG) and Healthy Building Network
(HBN), teamed up to conduct their own investigation. Analyzing
data from 180 different wood samples, these researchers
concluded that playing on pressure-treated wood is a greater
source of arsenic exposure for children than drinking
arsenic-contaminated drinking water.[24] (At the time this
report was released, spring 2001, the Bush administration had
just delayed the implementation of new, tighter drinking water
standards for arsenic -- to the outrage of many.) EWG and HBN
then petitioned the Consumer Product Safety Commission for an
immediate ban on the use of CCA wood in play equipment and a
recall on existing structures.[25] The Commission responded by
launching a new risk assessment. As did the EPA.

Also in spring 2001, an investigative journalist in Florida,
Julie Hauserman of the St. Petersburg Times, wrote a Sunday
story, "The Poison in Your Backyard," that brought the issue to
the public at last.[26] The result of months of investigation,
Hauserman collected soil beneath playgrounds in a five-county
area and sent it to labs for testing. Working closely with
scientists at the University of Florida and the University of
Miami, she also looked at what happens to the arsenic in
pressure-treated wood dumped in landfills -- an issue that took
on new urgency in the aftermath of Hurricane Andrew, when tons
of demolition materials were added to the waste stream.

"Arsenic," Hauserman wrote, "is leaking out of huge wooden
playgrounds that volunteers built all over Tampa Bay. It's
leaking beneath decks and state park boardwalks, at levels that
are dozens of times -- even hundreds of times -- higher than
the state considers safe. And discarded pressure-treated lumber
is leaking arsenic out of unlined landfills... posing a threat
to drinking water."

The spring 2001 publication of Hauserman's investigation was a
cultural tipping point. Time magazine, the New York Times, and
the Los Angeles Times all followed up with investigative
stories of their own, as did local television stations
throughout the country. Bills were introduced in Congress and
in the Florida legislature; class actions suits were filed.[29]

Many parents, school boards, and parks superintendents did not
wait for the outcome of these legal initiatives. Day care
centers ripped out play structures. Arsenic-contaminated
playgrounds closed throughout Florida and around the nation --including
some in Rochester, New York, where citizen activists
had been unsuccessfully pushing for their closure since
1990.[28] In May 2001, the city council of Cambridge,
Massachusetts passed a resolution to "replace all existing City
playground and park equipment constructed with CCA-treated wood
with arsenic-free alternatives on an expedited, specific time

The following fall, EWG and HBN released a new report about
arsenic levels in lumber purchased at Lowe's and Home Depot.
Shoppers were sent into retail outlets in 13 states to purchase
pressure-treated lumber. (Note: not a single buyer was offered
the safety warnings required by law.) Arsenic was easily wiped
off the surface of all purchased wood -- at levels up to 1,000
micrograms per 100 square centimeters, which is about the size
of a four-year-old's handprint. This was considerably more
arsenic than the EPA's allowable exposure level for arsenic in
drinking water.[30]

Good investigative journalism, combined with the advocacy work
of EWG and HBN, had a powerful effect. Catapulting the issue of
pressure-treated wood further up the chain of command was
blue-chip science. In September 2001, the National Academy of
Sciences announced, based on new findings from Chile and
Taiwan, that the cancer risks from arsenic in drinking water
were even greater than estimated in their ground-breaking 1999
report.[31] The EPA now had little choice about adopting the
stricter drinking water standards that it had been quietly
trying to back away from. And the dangers of arsenic were in
the news again.

In February 2002, the EPA announced that it had reached an
agreement with the timber industry: CCA production would be
phased out over a 22-month period.[32] This delay was to allow
wood treatment facilities to convert to alternative chemicals,
such as ACQ, a copper-based preservative. (Arsenic-free ACQ
wood has been available in Europe for many years. Because it
contains more copper, it is more expensive than CCA.) As of
January 1, 2004, CCA would no longer be registered for use to
treat wood intended for residential settings. While stores
would still legally be allowed to sell left-over stock after
the New Year's Eve deadline, the vice president of
merchandizing for Home Depot pledged in the pages of the
Washington Post that the process of phasing in alternatives to
CCA wood "will be complete by December 31."[33]

It was not. At this writing, the shelves of many home
improvement stores are still full of CCA lumber for sale to
unsuspecting buyers. The ban is still on the books -- but not
in the stores, many of which have enough stock to last for
months to come.[34] Moreover, there is still no plan to
remediate all the structures already built from CCA wood. What

[To be continued.]


*Sandra Steingraber, Ph.D., is a biologist and author (see
Rachel's #565, #658, #776, #777). She is currently a
Distinguished Visiting Scholar in the Interdisciplinary Studies
Program at Ithaca College in Ithaca, New York.

The following web sites are all excellent sources of
information on CCA wood and provide assess to many key
documents and reports:

http://www.ccaresearch.org http://www.bancca.org http://www.noccawood.ca
http://www.beyondpesticides.org http://www.healthybuilding.net

[1] European Environment Agency, Late Lessons from Early
Warnings: The Precautionary Principle 1896-2000 (Luxembourg:
Office for Official Publications of the European Communities,
2001) Available at

[2] Late Lessons, p. 11.

[3] David Gee, personal communication (david.gee@eec.eu.int).

[4] C. Cox, "Chromated Copper Arsenate," Journal of Pesticide
Reform Vol. 11 (1991), pgs. 2-6.

[5] U.S. Environmental Protection Agency, "Cancellation of
Residential Uses of CCA-Treated Wood: Questions and Answers,"
(20 March 2003;

[6] U.S. Environmental Protection Agency, A Probabilistic Risk
Assessment for Children Who Contact CCA-Treated Playsets and
Decks (13 Nov. 2003;
ssmentnov03.pdf )

[7] N. Tulve and others, "Frequency of Mouthing Behavior in
Young Children," Journal of Exposure Analysis and Environmental
Epidemiology Vol. 12 (2002), pgs. 259-64.

[8] U.S. Agency for Toxic Substances and Disease Registry,
"ToxFAQs for Arsenic," 2001;

[9] D.A. Belluck and others, "Widespread Arsenic Contamination
of Soils in Residential Areas and Public Spaces: An Emerging
Regulatory or Medical Crisis?" International Journal of
Toxicology Vol. 22 (2003), pgs. 109-128.

[10] Evidence is reviewed in Belluck (see note 9 above.)

[11] P.A. Cooper, "Future of Wood Preservation in Canada:
Disposal Issues," paper presented at the 20th Annual Canadian
Wood Preservation Association Conference, Vancouver, BC

[12] I. Lerner, "Potential Litigation Creates Concern for Wood
Preservatives," Chemical Market Reporter, 14 Oct. 2002, p. 14

[13] D. Hopey, "Wood Treatment Linked to Dangers," Pittsburgh
Post-Gazette 25 Jan. 1998. (Available on

[14] C. Rist, "Arsenic and Old Wood," This Old House, Mar.
1998, pp. 118-25.

[15] Belluck (cited above in note 9). (See also historical
timeline provided on http://www.bancca.org.)

[16] This history is described in Cox, 1991 (see note 4,
above). See also G. Kidd, "CCA-Treated Lumber Poses Danger from
Arsenic and Chromium, Pesticides and You Vol. 21 (2001), pgs.
13-15. (Available on http://www.beyondpesticides.org.)

[17] J. Hauserman, "Treated Wood Industry Fights Back," St.
Petersburg Times, 2 July 2001;

[18] W. Takahashi and others, "Urinary Arsenic, Chromium, and
Copper Levels in Workers Exposed to Arsenic-Based Wood
Preservatives," Archives of Environmental Health Vol. 38
(1983), pgs. 209-14; Cox, 1991 (cited in note 4, above); H.A.
Peters and others, "Seasonal Arsenic Exposure from Burning
Chromium-Copper-Arsenate Treated Wood," Journal of the American
Medical Association Vol. 251 (1984), pgs. 2393-96.

[19] U.S. Consumer Product Safety Commission, Estimate of Risk
of Skin Cancer from Dislodgeable Arsenic on Pressure-Treated
Wood Playground Equipment (Washington, D.C., 1990).

[20] National Research Council, Arsenic in Drinking Water
(Washington, D.C.: National Academy of Sciences, 1999).

[21] R.C. Kaltreider at al, "Arsenic Alters the Function of
Glucocorticoid Receptor as a Transcription Factor,"
Environmental Health Perspectives Vol. 109 (2001), pgs. 245-51.

[22] D. Stilwell and K.D. Gorny, "Contamination of Soil with
Copper, Chromium, and Arsenic Under Decks Built from
Pressure-treated Wood," Bulletin of Environmental Contamination
and Toxicology Vol. 67 (1997), pgs. 303-08.

[23] Belluck (cited above in note 9).

[24] Environmental Working Group and Healthy Building Network,
Poisoned Playgrounds: Arsenic in Pressure-Treated Wood
(Washington D.C.: May 2001;

[25] Environmental Working Group and Healthy Building Network,
"Petition to the United States Consumer Product Safety
Commission to Ban Arsenic-Treated Wood in Playground Equipment
and Review the Safety of Arsenic-Treated Wood for General Use,"
May 22, 2001

[26] J. Hauserman, "The Poison in Your Backyard," St.
Petersburg Times, 11 March 2001.

[27] M. Dunne, interview with Julie Hauserman in SEJournal,
Society of Environmental Journalists, Winter, 2001, p. 1.

[28] Contact Rochesterians Against the Misuse of Pesticides for
this fascinating history: Judy Braiman, 716-383-1317.

[29] Cambridge (Mass.) City Council meeting, 7 May 2001.

[30] Environmental Working Group and Healthy Building Network,
The Poisonwood Rivals (Washington, D.C.: Nov. 2001;

[31] National Research Council, Arsenic in Drinking Water: 2001
Update (Washington, D.C.: National Academy of Sciences, 2001).

[32] U.S. EPA, 2003 (cited above in note 5).

[33] J.M. Lerner, "New Rules on Treated Wood to Change the
Backyard World," Washington Post, Sept. 6, 2003, p. G2.

[34] G.C. Bruno, "Confusing Phaseout," Gainesville Sun, Jan.
24, 2004.