United States
Environmental Protection
Agency
Office of
Public Affairs (A-107)
Washington DC 20460
July 1984
v>EPA Dioxin Facts
Answers to Commonly Asked Questions
What is dioxin?
The word dioxin is a generic term for a group of 75 related
compounds known as polychlonnated dibenzo-p-dioxms
(PCDDs), but m popular use it usually refers to the most toxic
and carefully studied of these compounds — 2,3,7,8-
tetrachlorodibenzo-p-dioxm, or 2,3,7,8-TCDD. or simply TCDD
Where does dioxin come from?
Nobody produces dioxin (TCDD) on purpose. It is an
unwanted but almost unavoidable by-product that comes
from manufacturing several commercial substances, chiefly
the pesticide 2,4,5-tnchlorophenol (2,4.5-TCP). This pesticide
is then used as a basic ingredient in the manufacture of
several other pesticides, including the herbicides 2,4,5-T and
silvex, and the bactencide hexachlorophene. (Pesticide is a
general term for chemical products used to destroy or control
unwanted insects, plants, fungi, mites, rodents, bacteria, or
other organisms-)
How does dioxin get into the environment?
TCDD can enter the environment in several ways; through
chemical products contaminated with dioxin; as a component
of the wastes that are produced in manufacturing these
products; and through the widespread use of contaminated
products. Combustion is another possible source of dioxin
contamination.
Dioxin can enter waterways and soil in stormwater runoff,
through industrial discharges, or by seeping from landfills that
contain dioxm-contammated wastes. Dioxm's solubility in
water is quite low. but it attaches itself to soil particles, thus
making it more likely to be found in the sediment than in the
water itself.
Once in the environment, dioxin can be very persistent. Its
half-life in soil is on the order of 5-10 years. Under special
circumstances, however, the ultraviolet radiation in sunlight
can degrade it over a shorter amount of time
How does dioxin affect people?
Although scientists disagree on the long-term health effects
of exposure to 2,3,7.8-TCDD, tests on laboratory animals
indicate that it is one of the most toxic man-made chemicals
known. Because information on effects to humans has come
mostly from accidental exposures, the data are not definitive
Scientists do agree, however, that exposure to TCDD can
cause a persistent skin rash called chloracne, as experienced
by some workers exposed to dioxin in the work place or
through industrial accidents. Tests on laboratory animals also
indicate that exposure may result m a rare form of cancer
called soft tissue sarcoma, liver dysfunction, elevated blood
cholesterol, nervousness, and other problems.
Much controversy still exists over the use of Agent
Orange, a dioxm-contammated defoliant used during the
Vietnam War, and whether some veterans and their children
may be suffering from delayed effects of the chemical
How do people generally come in contact with dioxin?
There are two exposure routes that present the greatest
possibilities for health risks One •$ through contact with
dioxm-contammated soil and the other is through eating
contaminated fish. Dioxm-contammated soil presents a
particular risk to children who ingest it.
At what levels is dioxin a danger to people?
The Centers for Disease Control (CDC) considers 1 part per
billion (ppb) of dioxin in soil to be a level of concern in
residential areas (CDC is the federal agency EPA relies on to
conduct site-specific exposure and risk assessments
whenever hazardous pollutants are found m soil at high
levels.) The Food and Drug Administration recommends
limiting consumption of fish with 25 parts per trillion (ppt) or
greater of dioxin to no more than one meal per week and not
eating any fish with greater than 50 ppt of dioxin.
EPA, m coniunction with these federal agencies and State
and local health agencies, will issue health advisories and
alert people to any precautions they need to take whenever
dioxin is detected at these levels. They will also decide what
further actions are necessary
Is it safe to swim or boat in water that contains dioxin?
Local health agencies post signs to alert people when they
should not be using a particular body of water for recreational
purposes Since dioxin does not readily dissolve .n water, but
instead attaches to particles and eventually settles to the
bottom, it is not likely to pose a threat to human health
unless you disturb any sediment in which diox;n has settled.
However, if you have any concerns whatsoever about the
safety of the water, for any reason, ask the advice of your
local health officials before swimming or boating.
Is it safe to drink water that contains dioxin?
Any drinking water that is suspected of being contaminated
with dioxin or any other hazardous chemical should not be
consumed. You should contact your local health department
to find out the facts, or heed any advice they have given you
They will also advise you on whether or not you should be
using an alternative drinking water source. Most water
treatment plants can eliminate dioxin during the water
treatment process by removing the sediment in which it
collects
Does dioxin affect animals?
The only known incident in the U.S. occurred in Missouri in
1971 when horse arenas were sprayed with high levels of
dioxm-contammated oil Hundreds of horses became sick and
65 of them died
What federal agencies are involved in dioxin detection
and cleanup?
EPA regulates dioxin under the Toxic Substances Control Act
and the Federal Insecticide, Fungicide, and Rodenticide Act
and is developing regulations to control it m wastes under
the Resource Conservation and Recovery Act. The Food and
Drug Administration issues health advisories for dioxin in
products for human consumption. The Occupational Safety
and Health Administration has jurisdiction over dioxin
exposure in the workplace Issues associated with dioxin in
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Agent Orange involving military personnel are handled by the
Veterans Administration (VA) and the Department of
Defense, although the VA has relinquished control of a
project to investigate a link between dioxin and Vietnam
veterans to the Centers for Disease Control.
What has industry done about the dioxin problem?
By 1965, some companies had changed their production
processes and increased quality control practices in an
attempt to reduce the levels of TCDD in the pesticide
2,4,5-T. As the controversy over dioxin increased, these
companies instituted practices to further lower dioxin levels,
and some companies ceased manufacturing the controversial
product altogether. Today there is no domestic manufacturer
of the pesticide 2,4,5-T.
What has the federal government done about the dioxin
problem?
In 1970, the Department of Health, Education, and Welfare
(now the Department of Health and Human Services), the
Department of Agriculture, and the Department of Interior
suspended many uses of the herbicide 2,4,5-T as a result of
a report by the National Institute for Environmental Health
Services that is caused birth defects in laboratory mice.
In 1970. the Department of Defense halted the spraying of
Agent Orange in Vietnam and in 1978, the Veterans
Administration created the Agent Orange Registry to identify
veterans who are concerned about possible exposure to
Agent Orange.
In 1979, on the basis of controversial evidence that linked
forest spraying of 2,4,5-T with an increase in miscarriages
among some Oregon women, EPA suspended use of silvex
and 2,4,5-T on forests, rights-of-way and pastures, but still
allowed spraying on rice fields, fence rows, vacant lots and
lumberyards.
In 1981, the Centers for Disease Control began a study to
determine if Vietnam veterans are at a greater risk of having
children with birth defects.
In 1981, the Food and Drug Administration banned the use
of hexachiorophene in nonprescription soaps and deodorants.
In 1981, the Food and Drug Administration recommended
that people not eat fish with dioxin levels greater than 50 ppt,
and limit their consumption of fish with 25-50 ppt of dioxin.
Fish with dioxin below the 25 ppt level are considered safe
to eat.
In 1982, EPA required some industries to certify that they
were no longer using chlorophenol-type compounds as slime
control agents.
In 1983, EPA proposed cancellation of all remaining 2.4.5-T
and silvex products. This action was appealed at a hearing by
a number of pesticide registrants and users. Until the
hearings are completed, as required by law, limited use of
2,4,5-T and silvex may continue.
In 1983, EPA initiated a National Dioxin Strategy to look for
areas throughout the country where 2,3,7,8-TCDD may be
present in the environment. The strategy provides a
systematic framework under which the agency will study the
nature of dioxin contamination throughout the U.S. and the
risks to people and the environment; clean up dioxin-
contaminated sites that threaten public health; find ways to
prevent future contamination; and find ways to destroy or
dispose of existing dioxin. A National Dioxin Study to
investigate the nature and extent of dioxin contamination in
the environment will begin this summer and take from 12-15
months. Air, water, soil, and fish sampling will take place in
over 1,000 locations across the country.
In 1984, EPA issued a water quality criteria document for
2,3,7,8-TCDD.
Are there ways to safely dispose of or destroy dioxin?
EPA is currently evaluating methods of disposing of or
destroying dioxin-contaminated soils and wastes. Established
technologies include incineration, chemical degradation, and
biological treatment measures, but EPA is working to find
other methods of disposal as well. One promising technique
is to treat soil with a chemical compound and sunlight. This
method holds promise for actually detoxifying the dioxin
molecule. Another alternative that is being investigated
involves the use of solvents to change dioxin into a soluble
form capable of destruction.
Some temporary methods to limit exposure include:
excavating highly contaminated soil and removing it to a
secure landfill or concrete vault; securing and capping the
contaminated area; and using high efficiency vacuums and
liquid dust suppressants.
Who can I contact if I have more questions about dioxin?
Each of EPA's 10 regional offices has a community involvement
contact who can answer your questions about dioxin. Following
are their names, addresses, and telephone numbers.
Debra Prybla
Office of Public Affairs
U.S. EPA Region 1
JFK Federal Building
Boston, MA 02203
Richard Cahill
Office of Public Affairs
U.S. EPA Region 2
26 Federal Plaza
New York, NY I0007
Joe Donovan
Office of Public Affairs
U.S. EPA Region 3
6th and Walnut Sts.
Phila., PA I9I06
Hagan Thompson
Office of Public Affairs
U.S. EPA Region 4
345 Courtland St., NE
Atlanta, GA 30308
Vanessa Musgrave
Office of Public Affairs
U.S. EPA Region 5
230 S. Dearborn
Chicago, IL 60604
(6I7) 223-4906
(2I2) 264-25I5
(2I5) 597-9370
(404) 88I-3004
(3I2) 886-6I28
Connecticut, Maine,
Massachusetts, New
Hampshire, Rhode
Island, Vermont
New Jersey, New York,
Puerto Rico, Virgin
Islands
Delaware, Maryland,
Pennsylvania, Virginia,
West Virginia. District
of Columbia
Alabama, Georgia.
Florida, Mississippi,
North Carolina, South
Carolina, Tennessee.
Kentucky
Illinois, Indiana. Ohio,
Michigan, Wisconsin,
Minnesota
Betty Williamson
Office of Public Affairs
U.S EPA Region 6
I20I Elm St.
Dallas, TX 75270
Steven Wurtz
Office of Public Affairs
U.S. EPA Region 7
324 E. llth St.
Kansas City, MO 64I06
Nola Cook
Office of Public Affairs
U.S. EPA Region 8
Suite 900
I860 Lincoln St.
Denver, CO 80295
Deanna Wieman
Office of External Affairs
U.S. EPA Region 9
2I5 Fremont St.
San Francisco, CA 94I05
Bob Jacobson
Office of Public Affairs
U.S. EPA Region 10
1200 Sixth Ave.
Seattle. WA 98IOI
2I4) 767-9986
(8I6) 374-5894
(303) 837-5927
(4I5) 974-8083
(206) 442-I203
Arkansas, Louisiana,
Oklahoma. Texas, New
Mexico
Iowa, Kansas, Missouri.
Nebraska
Colorado, Utah,
Wyoming, Montana,
North Dakota. South
Dakota
Arizona, California.
Nevada, Hawaii,
American Samoa,
Guam
Alaska, Idaho. Oregon,
Washington
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