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| Tire wall photo by Pratik Zaveri |
We do not have a vested interest in saying that the
off-gassing of the tires is a "non-issue." We do not believe
that your health is a non-issue. Neither do the countries that have banned the
use of tires in buildings. Because of laws prohibiting the use of tires, groups
like Earthship Belgium are using earthbags instead of tires for their
Earthships.
Just a few months ago, the tire off-gassing issue was raised again when The Washington
Post did a story on a number of soccer goalies who have contracted cancer.
Scientists and doctors began studying the unique subgroup, which led them to
pose a link between the incidents of cancer and goalies who had played
extensively on athletic fields paved with a form of AstroTurf that used crumb
rubber from recycled tires in its
makeup. While in its early stages now, this may ultimately prove to be fruitful
research to the
tire off-gassing issue.
Here is what we DO know, from the scientific studies and
best practices promoted by experts in the many fields which influence our
assertion that the tires are
dangerous, so you can decide what works for you!
The laundry list of volatile chemicals used in tires is alarming:
·
Benzene inhalation causes cancer
·
Toluene inhalation causes cognitive disfunction
·
Arsenic inhalation causes organ failure
·
Acetone inhalation
causes irritation of the throat and lung
plus heavy metals that include
·
Nickel inhalation causes sinusitis and
cancer
·
Copper inhalation causes nausea
and suppressed liver function
·
Cadmium inhalation causes kidney disease and
an increased frequency of kidney stone formation
Organic compounds in tires break down more quickly than the
vulcanized rubber. Criteria which determine breakdown rate include: heating,
friction (from movement), water trapping and freezing, and evaporation of
plasticizers.
But here is where it gets REALLY interesting. Here are
scientific studies done for several different materials, all of which are
constructed of recycled tires.
According to the EPA report, “Scrap Tires: Handbook on Recycling
Applications and Management for the U.S. and Mexico” from December 2010;
“These (tire) piles pose a public
health concern. They are breeding grounds and havens for mosquitoes and other
vectors, resulting in the spread of dengue fever, yellow fever, encephalitis,
West Nile virus, and malaria. Improperly managed in stockpiles, in illegal
dumps, and scattered along road sides, scrap tires are a significant border
environmental problem as a result of the leaching process, fires hazards, and
water contamination. Once ignited, tire fires are difficult to extinguish. When
water is applied to fight the fire, serious air, ground water, and surface
water contamination may result. Toxic emissions from tire fires, such as
sulfuric acid and gaseous nitric acid, can irritate the skin, eyes, and mucus
membranes, and can affect the central nervous system, cause depression, have
negative respiratory effects and, in extreme cases, cause mutations and
cancer.”
"The metals zinc, cadmium, and lead were also identified as
contaminants from tire rubber released into ground water. With the exception of
zinc, there are insufficient data to assess the health or environmental risks
of any of these metals. It appears clear that the zinc levels are high enough
to be phytotoxic if they enter the ground water or soil. It is doubtful that
there is any human toxicity from zinc at the levels reported, but such a
conclusion would have to be tested by more careful study."
"The particulate exposures due to tire dust and chemicals
contained in the dust that can be released in the lungs are especially
troublesome. Nearly every test adequate to assess the risk that was reported
found one or two dozen compounds released from particulates. There are
processes in the body that can release the chemicals contained in the rubber
particles. Moreover, potent carcinogens are found in the tire dust. Only the
assumption of limited exposure could support the conclusions of low cancer
risk."
"In summary, the toxic actions of concern from the materials…
include: Severe irritation of the respiratory system; Severe irritation of the
eyes, skin and mucous membranes; Systemic effects on the liver and kidneys;
Neurotoxic responses; Allergic reactions; Cancers; Developmental effects"
2012 Cal Recycles Report on Tire Breakdown, which states:
" Natural rubber alone poses a dangerous fire hazard and when
heated to decomposition emits toxic fumes of SOx. Base materials used in
polymer rubber production, such as butadiene and styrene, are suspected human
carcinogens, and many of the polymer additives can cause systemic toxic
effects."
"The tire filler, carbon black, is mildly toxic by ingestion,
inhalation and skin contact."
"Isoprene is a mild toxic by the pathway of inhalation. It
also reacts with air and ozone to form dangerous peroxides. Butadiene is a
confirmed carcinogen and teratogen in animals and a suspected human carcinogen.
Inhalation of high concentrations of butadiene can cause unconsciousness and
death. Human systemic effects of butadiene by inhalation include coughing and
hallucinations. Styrene is a suspected carcinogen. It has been found to be
poisonous by ingestion, inhalation, and intravenous routes."
"Zinc oxide is added to tire rubber at relatively high
concentrations. Zinc oxide is moderately toxic to humans by ingestion. Some
human systemic effects associated with the inhalation of zinc oxide are chills,
fever, tightness of the chest, and coughing."
"Increased incidences of lung tumors were observed in female
rats exposed by inhalation to the only or lowest concentration (of carbon
black) tested..."
"The 2007 EEDEMS report mentioned above raised concerns about
health effects on the crews installing crumb rubber athletic fields in poorly
ventilated indoor areas and recommends a minimum air renewal rate of 2 vol.h-1.
A 2006 study conducted in Norway drew a similar conclusion... These recent
findings are consistent with those of a 1999 Taiwanese study that identified
temperature and age of the recycled rubber material as the primary factors in
VOC emission rates."
And then you read statements from industry professionals dealing with tire decompositions in their everyday lives, who say things like...
"While the levels of
chemicals off-gassing from indoor play spaces was considered below the
threshold where the chemicals are harmful, it is worth noting that indoor
spaces showed up to ten times as much volatile chemicals in the air. If you
want to err on the side of caution, you may want to consider refraining from
using recycled rubber mats indoors, where there is a minuscule but present
danger that could deem recycled rubber unhealthy." in "Are Recycled Rubber Mats
Unhealthy?" by Lara Stewart at BrightHub based on the research noted
in the first report we suggested reviewing.
"Minor off-gassing is an
issue with rubber flooring. The gasses have an odor but will not release
hazardous chemicals. In some cases, products with recycled content are included
with caveats regarding where they should be used. Rubber flooring made from
recycled automobile tires is a good example--the caveat is that these products
should not be used in most fully enclosed indoor spaces due to offgassing
concerns." from "Building Materials: What Makes a Product Environment
Friendly?"at
Earthwise.com
"Do not use rubber flooring,
such as that made from recycled tires, in enclosed areas because off gassing
can continue for years." "Healthy Indoor
Environments" at
The Sustainability Project.
But then, to be fair, we cannot ignore this archived, undated, report from Humbolt State University, which addresses the risks in earthships directly.
“Reusing our worn out tires is of
course better than throwing them into a landfill, but many of the current reuse
applications found in our society come with significant environmental impacts.
One appropriate use for old tires
is in Earthship homes. A question we
frequently receive … is if the tires used in these projects pose health risks
through offgassing or chemical leaching.
“it depends”.
The specific constituents
contained in a given tire (e.g. arsenic, aluminum, cadmium, chromium,
manganese, mercury, lead, sulfur, and zinc) are dependent on the tire’s type,
age, and manufacturer. The location in
which the used tires are placed is a critical factor that determines how much
of each mineral constituent is leached.
Tires decompose when exposed to high temperatures, sunlight, or
oxidizing agents. None of these elements
are present when a tire is packed with soil and surrounded by a stucco barrier
inside an Earthship. That being said,
the tires used in Earthship walls are of minimal risk to inhabitants because
they have little potential to decompose.
…used tires most likely do not
pose a health risk if they are rammed with earth and sequestered in a location
away from exposure to sun or moisture… EPA researchers have acknowledged that
the current literature we have pertaining to the health risks that used tires
pose is incomplete, and that further study should be conducted before used
tires are used in applications where humans are exposed”
Once you have read some of these reports, or just the
excerpts we have included here... ask yourself, is it worth the chance you
take? If your answer to this is yes, Part 2 of the book has suggestions for
making them work. If the answer is no, then Part 2 will also offer viable
alternatives!
