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Executive Summary
As the new home of Maryland PIRG's environmental work, Environment Maryland can be contacted regarding this report.
Chlorinating tap water is a critical public
health measure that saves thousands of lives
each year by reducing the incidence of waterborne
disease. But chlorination is no substitute
for cleaning up America’s waters.
By failing to clean up rivers and reservoirs
that provide drinking water for hundreds of
millions of Americans, EPA and the Congress
have forced water utilities to chlorinate water
that is contaminated with animal waste, sewage,
fertilizer, algae, and sediment, in order to provide
water free of disease-causing microorganisms.
Chlorine combined with the organic
matter in this pollution produces harmful
byproducts, collectively referred to as chlorination
byproducts (CBPs). In spite of the diligent
efforts of the water utilities to filter and clean the
water before they chlorinate, CBP levels remain
high in the water consumed by millions of
people each day. Approximately 240 million
Americans drink tap water contaminated with
some level of CBPs.
A compelling body of scientific evidence - nearly 30 peer-reviewed
epidemiologic studies - links chlorination byproducts to increased risks of
cancer. At current levels in U.S. tap water, EPA estimates that CBPs cause
up to 9,300 cases of bladder cancer each year. A growing body of science
links CBPs to miscarriages and birth defects, including neural tube defects,
low birth weight, and cleft palate. Other health problems from CBP exposure
may include other cancers (rectal and colon), kidney and spleen
disorders, immune system problems and neurotoxic effects (63 FR 69390-
69476).
Industrial water pollution is not a major contributor to CBPs in tap water.
Instead the main causes are sediments, nutrients, and pollution from agricultural
and urban runoff, and in some small systems, excess use of chlorine.
Until Congress and the EPA act to limit pollution from farms and urban
runoff so that water entering drinking water treatment plants is much
cleaner than it is today, CBPs will remain at unacceptably high levels.
We recommend:
• A major national effort to clean up
drinking water sources, focusing on
reducing agricultural and urban
pollutants that lead to chlorination
byproducts.
• The creation of a nationwide health
tracking network to help scientists and
policymakers fully understand the link
between tap water chlorination
byproducts and specific birth defects,
cancers, and miscarriage.
• Funding for programs to train operators
of small town drinking water systems in
improved chlorination techniques.
This first ever national analysis of chlorination byproducts in tap water
from both large and small cities, conducted by the Environmental Working
Group (EWG), shows that although most water suppliers are in compliance
with current and future drinking water standards:
• More than 137,000 pregnancies each year are at increased risk of
miscarriage and birth defects each year from exposure to CBPs in tap
water.*
• Since 1995, more than 16 million people in 1,258 communities have
been served water containing chlorination byproducts for 12 months
in a row at levels above the legal limit going into effect in January
2002.*
• A handful of large cities with a history of high CBP levels account for
a significant portion of the population at risk, including Washington,
DC suburbs, Philadelphia, Pittsburgh suburbs, and San Francisco..
• The problem is not confined to large cities. More than 1,100 small
towns (fewer than 10,000 people) have reported potentially dangerous
levels of CBPs in their tap water over the past six years. Pregnant
women living in small towns supplied by rivers and reservoirs are
more than twice as likely to drink tap water with elevated levels of
CBPs as women in larger communities. Historically, systems serving
fewer than 10,000 people have been exempt from all federal health
standards for CBPs.
Despite significant population-wide exposures to CBPs, a survey of
federal and state-level efforts to monitor and track consumers’ exposure to
CBPs and related health effects shows that the U.S. fails to collect essential
tracking data at a national level that could provide key insight on causes
and other critical information on miscarriages and birth defects linked to
CBPs.
EWG and U.S. Public Interest Research Group’s (U.S. PIRG’s) compilation
of survey information finds that 10 states and Washington, D.C., either have
no birth defects surveillance system at all, or cursory systems that miss an
estimated 90 percent of the cases. Not a single state has an active, wellfunded
system in place to track first-trimester miscarriages, which account
for 90 percent of all miscarriages and which also have been linked to CBP
exposures.
The need for a nationwide health tracking network
In 1998, EPA completed a revision of the health standard governing two groups of chlorination byproducts in tap water. The new rule makes three major changes in policy. First, it eliminates the long standing exemption from health standards for systems serving less than 10,000 people; second, it
lowers the amount of trihalomethanes (THMs, the most prevalent chlorination
byproducts) allowed in tap water from 100 parts per billion on average
over the course of a year, to 80 ppb; and third, it regulates haloacetic acids,
another major class of chlorination byproducts, and two other byproducts
called chlorite and bromate, for the first time.
The effectiveness of health standards for CBPs and other environmental
contaminants is limited by the lack of reliable data on environmentally
caused disease. In spite of the growing body of evidence linking CBPs to
miscarriages, birth defects, and cancers, EPA lacked solid data on incidence
rates for most of these effects, as well as exposure data to CBPs in tap
water, throughout the standard setting process. The United States lacks a
nationwide health tracking network that could provide reliable data on
disease rates, pregnancy outcomes, and levels of exposure to environmental
contaminants potentially responsible for harm.
Because of these data limitations, EPA formally considered the risks of
just one cancer, bladder cancer, when setting the new health limits for
CBPs. The agency made no estimate of the risk or potential reduction in
the rates of other cancers, birth defects or miscarriages during the entire
process (63 FR 69390-69476). The result is most likely an underestimate of
the actual risk, and new health standards that may not significantly reduce
the incidence of adverse health effects from CBPs.
EPA’s ability to quantify just one of the many health effects linked to CBP
exposures (bladder cancer), illustrates how our country’s patchwork of
health tracking programs ultimately hamstrings public health officials,
forcing decisions that more often than not are based on just a fraction of the
public health impacts from environmental contaminants. Tracking disease is
a cornerstone of public health protection, and has been used effectively to
identify and stop infectious disease outbreaks for decades. Nationwide, the
tools of tracking and monitoring have not been consistently applied to
chronic disease; birth defects and other conditions ranging from Alzheimer’s
Disease to asthma to miscarriage remain inadequately tracked in the U.S.
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