Environmental Impacts of
Polyvinyl Chloride (PVC)
Building Materials
by
CONTENTS
Summary of Findings
Introduction
Purpose
The lifecycle
of PVC
International
action on PVC
PVC and chlorine
chemistry
PVC Production
Production
of chlorine
Synthesis of EDC
and VCM - dioxin
Polymerization,
compounding, and molding
Disposal of EDC/VCM
wastes
The Vinyl Institute’s
self-characterization of dioxin releases
Use of PVC
products
By-product
formation
Indoor air quality:
release of toxicants
Accidental combustion
Disposal of
PVC Products
Recycling
Land Disposal
Incineration
Background
on Persistent Organic Pollutants (POPs)
Global
distribution of POPs
Endocrine disruption
Dioxin and related
compounds
Phthalates
Trends in PVC
Markets
Conclusion
References
SUMMARY OF FINDINGS
In the last 40 years, polyvinyl chloride
plastic (PVC) has become a major building material. Global vinyl production now totals over 30
million tons per year, the majority of which is directed to building applications,
furnishings, and electronics.
The manufacture, use, and disposal of PVC
poses substantial and unique environmental and human health hazards. Across the world, governments, companies,
and scientific organizations have recognized the hazards of PVC. In virtually all European nations, certain
uses of PVC have been eliminated for environmental reasons, and several
countries have ambitious programs to reduce PVC use overall. Scores of communities have PVC avoidance
policies, and dozens of green buildings have been built with little or no
PVC. Firms in a variety of industries
have announced measures to reduce PVC consumption and are using or producing
alternative materials in a variety of product sectors, including building
materials. This paper discusses the hazards of the PVC lifecycle that have led
to this large scale movement away from PVC products.
The major hazards of the PVC lifecycle
discussed in this report are summarized below.
PVC production is the largest use of chlorine gas in
the world. PVC consumes about 40
percent of total chlorine production, or approximately 16 million tons of
chlorine per year worldwide. PVC is the
largest production-volume organochlorine, a large class of chemicals that have
come under scientific and regulatory scrutiny in the last decade because of
their global distribution and the unusually severe hazards they tend to
pose. PVC (vinyl) is the only major
building material that is an organochlorine; alternative materials, including
most other plastics, do not contain chlorine and do not pose the hazards
discussed in this report.
Hazardous by-products are formed throughout the PVC
lifecycle. At numerous points in the vinyl lifecycle,
very large quantities of hazardous organochlorine by-products are formed
accidentally and released into the environment.
Production:
Formation of hazardous organochlorine by-products begins with the production of
chlorine gas. Extremely large
quantities - on the order of one million tons per year -- of chlorine-rich
hazardous wastes are generated in the synthesis of ethylene dichloride and
vinyl chloride monomer (EDC and VCM, the feedstocks for PVC).
Combustion:
Still more by-products are created and released to the environment during the
incineration of hazardous wastes from EDC and VCM production, the incineration
of vinyl products in the waste stream, the recycling of vinyl-containing metal
products by combustion, and the accidental burning of PVC in fires in
buildings, warehouses, or landfills.
By-products of PVC production are highly persistent,
bioaccumulative, and toxic. The chemical mixtures produced in the
synthesis of EDC and VCM include such extremely hazardous and long-lived
pollutants as the chlorinated dioxins (polychlorinated dibenzo-p-dioxins),
chlorinated furans (polychlorinated dibenzofurans), PCBs (polychlorinated
biphenyls), hexachlorobenzene (HCB), and octachlorostyrene (OCS). In addition, a very large portion of these
mixtures consists of chemicals that have not yet been identified or tested.
Many of the by-products of the vinyl lifecycle are of great concern, because of
their persistent bioaccumulative toxicity:
Persistence
means that a substance resists natural degradation, builds up over time in the
environment, and can be distributed globally on currents of wind and
water. Many of the by-products of the
PVC lifecycle are now ubiquitous global pollutants, which can be found not only
in industrialized regions but in the planet’s most remote ecosystems. Absolutely every person on earth is now exposed
to these substances.
Bioaccumulation means that a substance is fat-soluble and therefore builds up in the
tissues of living things. Most
bioaccumulative substances, including many formed during the PVC lifecycle,
magnify as they move up the food chain, reaching concentrations in species high
on the food chain that are millions of times greater than their levels in the
ambient environment. These substances also cross the placenta easily and
concentrate in the breast milk of human and other mammals.
Toxicity. The feedstocks, additives, and by-products
produced and released during the lifecycle of PVC have been shown to cause a
range of health hazards, in some cases at extremely low doses, including:
·
Cancer
·
Disruption of the endocrine system
·
Reproductive impairment
·
Impaired child development and birth defects
·
Neurotoxicity (damage to the brain or its function), and
·
Immune system suppression.
Dioxins. Among the most important by-products of the
PVC lifecycle are dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin) and a large
group of structurally and toxicologically related compounds, collectively
called dioxins or dioxin-like compounds. Dioxins are never manufactured intentionally
but are formed accidentally whenever chlorine gas is used or chlorine-based
organic chemicals are burned or processed under reactive conditions.
Dioxins are
formed during numerous stages of the vinyl lifecycle Formation of dioxins has been documented in
production of chlorine, synthesis of the feedstocks EDC and VCM, burning of
vinyl products in accidental fires, and incineration of vinyl products and the
hazardous wastes from PVC production.
Vinyl is a major dioxin source. Vinyl is the predominant chlorine donor
and therefore a major and preventable cause of dioxin formation in most of the
leading dioxin sources that have been identified. When its entire lifecycle is considered,
vinyl appears to be associated with more dioxin formation than any other single
product.
Dioxins are global pollutants. Dioxins are now found in the tissues of
whales in the deep oceans, polar bears in the high
There is no known safe dose of dioxin. Dioxin causes damage to development,
reproduction, and the immune and endocrine systems at infinitesimally low doses
(in the low parts per trillion). Toxicological studies have not been able to
establish a “threshold” dose below which dioxin does not cause biological
impacts.
Dioxin is a potent carcinogen. Dioxin is the most potent synthetic
carcinogen ever tested in laboratory animals and is a known human carcinogen.
Dioxin poses health risks to the general
public that are already too high. The dioxin “body burden” of the general human population of the
Phthalate
plasticizers. In its pure form, PVC is rigid and
brittle. To make flexible vinyl
products, such as roofing materials, floor tiles and wall coverings,
plasticizers must be added to PVC in large quantities - up to 60 percent of the
final product by weight. The dominant
group of plasticizers used in vinyl are a class of compounds called phthalates,
which pose considerable health and environmental hazards. Vinyl is the only major building product in
which phthalates are used extensively, and it accounts for about 90 percent of
total phthalate consumption. Over 5
million tons of phthalates are used in vinyl every year.
Phthalates
have become global pollutants. Phthalates are moderately bioaccumulative and moderately
persistent under some conditions. They
can now be found in the water of the deep oceans, air in remote regions, and
the tissues and fluids of the general human population. Infants and toddlers
are subject to exposures several times higher than those of the average adult.
Massive
quantities of phthalates are released into the environment each year. Millions of pounds of phthalates are
released annually into the environment during the formulation and molding of
vinyl products. Phthalates are also
released when vinyl is disposed of in landfills or incinerators or when PVC
products burn accidentally. More than 80
million tons of phthalates are estimated to be contained in the stock of PVC
products now in use in buildings and other applications.
Phthalates
leach out of vinyl products. Phthalates are not chemically bonded to the plastic but are
merely mixed with the polymer during formulation. They therefore leach out of the plastic over
time into air, water, or other substances with which vinyl comes in contact.
Phthalates
damage reproduction and development. Phthalates have been found to damage the
reproductive system, causing infertility, testicular damage, reduced sperm count,
suppressed ovulation, and abnormal development and function of the testes and
male reproductive tract in laboratory animals. They are known carcinogens in
laboratory animals.
DEHP
exposure is already too high. An expert committee of the National Toxicology Program recently
reviewed the hazards of diethylhexyl phthalate (DEHP, the most common vinyl
plasticizer) and expressed “concern that exposure [of infants and toddlers in
the general U.S. population] may adversely affect male reproductive tract development”
and “concern that ambient oral DEHP exposures to pregnant or lactating women
may adversely affect the development of their offspring.” The average
American’s dose of the plasticizer DEHP is now approximately equal to EPA’s
reference dose - the maximum “acceptable” exposure based on studies of health
impacts in laboratory animals.
Lead
and other heavy metal stabilizers. Because PVC catalyzes its
own decomposition, metal stabilizers are added to vinyl for construction and
other extended-life applications. Common PVC additives that are particularly
hazardous are lead, cadmium, and organotins, with global consumption of each by
vinyl estimated in the thousands of tons per year. .
Metals
do not degrade in the environment. All three of the major
PVC stabilizers resist environmental breakdown and have become global
pollutants.
Metal
stabilizers are highly toxic. Lead is an exquisitely potent developmental toxicant, damaging
brain development and reducing the cognitive ability and IQ of children in
infinitessimal doses. Cadmium is a potent neurotoxin and carcinogen, and
organotins can suppress immunity and disrupt the endocrine system.
Metal
stabilizers are released through out the vinyl product lifecycle. Metal stabilizers are released from vinyl
products when they are formulated, used, and disposed. Releases of lead stabilizers from interior
vinyl building products have been documented.
Metals cannot be destroyed by incineration but are released entirely
into the environment, via air emissions or ash residues. Trash incinerators are a dominant source of
lead and cadmium pollution, and PVC contributes a significant amount of these
metals - an estimated 45,000 tons of lead each year -- to incinerators.
Accidental fires in buildings and
landfills are also potentially important sources of lead, cadmium, and
organotins. In a fire, metals in PVC
will be released to the environment; an astounding 3.2 million tons of lead are
present in the current stock of PVC in use.
Potential lead releases from this stored PVC must be viewed as a major
potential health hazard.
Flexible
PVC harms indoor air quality. Flexible vinyl products
appear to contribute to the health hazards of poor indoor air by releasing
phthalates and facilitating the growth of hazardous molds.
PVC
products release phthalates into the building environment.
Phthalate levels in indoor air in buildings with PVC are typically many
times higher than in outdoor air.
Phthalate accumulation in suspended and sedimented indoor dusts are particularly
high, with concentrations in dust as high as 1,000 parts per million.
PVC
phthalate exposure may be linked to asthma. In laboratory animals, metabolites of phthalates used in
vinyl cause asthma-like symptoms through a well-described inflammatory
mechanism. Three separate
epidemiological studies have found that human exposure to PVC in building
interiors causes significantly elevated risks of asthma and other pulmonary
conditions, including bronchial obstruction, wheezing, pneumonia, prolonged
cough, and irritation of the nasal passages and eyes.
PVC
products can release heavy metals into the building environment. Metal stabilizers, particularly lead,
cadmium, and organotins, can be released from vinyl products. Significant quantities of lead have been
found to be released from vinyl window blinds into air and from PVC pipes into
water. Toxicological effects of these substances include neurological,
development, and reproductive damage.
Vinyl
wall covering encourages toxic mold growth. Because vinyl wall coverings form a barrier impermeable to
moisture, they encourage the growth of molds on wall surfaces beneath the
vinyl, particularly in buildings where air conditioning or heating systems
produce significant temperature and humidity differentials between rooms and
wall cavities. Some molds that grow
beneath vinyl produce toxic substances that are released into indoor air and
are suspected causes of severe human health problems. Numerous liability suits are active on the
link between vinyl-produced molds and respiratory and neurological symptoms
among exposed persons. Vinyl has been cited as the interior building material
most likely to facilitate the growth of these molds.
Workers
and communities are exposed to toxic substances due to PVC production. In the production of PVC, many thousands
of tons per year of the feedstocks ethylene dichloride (EDC) and vinyl chloride
monomer (VCM) are released into the workplace and into local environments.
PVC
feedstocks cause cancer and other health impacts. Both EDC and VCM cause cancer in
laboratory animals; VCM is classified as a known human carcinogen and EDC is a
probable human carcinogen. Increased risks of liver cancer and brain cancer
have been documented among workers exposed to VCM. They are toxic to the nervous system and
cause a variety of other impacts on human health There is preliminary evidence
that workers involved in the manufacture of PVC products may have elevated
risks of testicular cancer.
There
is no safe VCM exposure level. Although workplace exposures in
VCM
production facilities are major polluters. Severe contamination of communities and waterways in the
vicinity of VCM production facilities has been documented. In
Chlorine
production consumes enormous amounts of energy. Chlorine production is one of the world’s most
energy-intensive industrial processes, consuming about 1 percent of the world’s
total electricity output. Chlorine
production for PVC consumes an estimated 47 billion kilowatt hours per year -
equivalent to the annual total output of eight medium-sized nuclear power
plants.
Chlorine
production causes mercury
pollution. The mercury-based process
for producing chlorine accounts for about a third of world chlorine
production. In this process, very large
quantities of mercury are released into the environment. Mercury is now a
global pollutant that causes severe reproductive, developmental, and
neurological impacts at low doses. The vinyl lifecycle is associated with the
continuing release of many tons of mercury into the environment each year.
PVC
is extremely difficult to recycle. Very little PVC is
recycled, and this situation is unlikely to change in the foreseeable
future. Because each PVC product
contains a unique mix of additives, post-consumer recycling of mixed PVC
products is difficult and cannot yield vinyl products with equivalent qualities
to the original. Even in
PVC
is one of the most environmentally hazardous consumer materials ever produced. The PVC lifecycle presents one opportunity after
another for the formation and environmental discharge of organochlorines and
other hazardous substances. When its entire lifecycle is considered, it becomes
apparent that this seemingly innocuous plastic is one of the most
environmentally hazardous consumer materials produced, creating large
quantities of persistent, toxic organochlorines and releasing them into the
indoor and outdoor environments. PVC has contributed a significant portion of
the world’s burden of persistent organic pollutants
and endocrine-disrupting chemicals-including dioxins and phthalates-that are
now present universally in the environment and the bodies of the human
population. Beyond doubt, vinyl has caused considerable occupational disease
and contamination of local environments as well.
In
summary, the feedstocks, additives, and by-products of the PVC lifecycle are
already present in global, local, and workplace environments at unacceptably
high levels. Efforts to reduce the production and release of these substances
should be environmental and public health priorities.
It
is time to phase out PVC building materials. The hazards posed by dioxins, phthalates, metals, vinyl chloride, and
ethylene dichloride are largely unique to PVC, which is the only major building
material and the only major plastic that contains chlorine or requires
plasticizers or stabilizers. PVC
building materials therefore represent a significant and unnecessary
environmental health risk, and their phase-out in favor of safer alternatives
should be a high priority.
PVC is the antithesis
of a green building material. Efforts to speed adoption of safer, viable substitute
building materials can have significant, tangible benefits for human health
and the environment.
About the Author
Joe Thornton, Ph.D., is a postdoctoral research scientist in
Dr. Thornton is the author of Pandora’s
Poison: Chlorine, Health, and a New Environmental Strategy (MIT Press
2000), which the British scientific journal Nature has called “a landmark
book which should be read by anyone wanting to understand the environmental
and health dangers of chlorine chemistry.” From the late 1980s to the mid-1990s,
This report was prepared by the author and
does not represent the opinions of