xvEPA
United States
Environmental Protection
Agency
Technical Fact Sheet -
1,4-Dioxane
May 2012
TECHNICAL FACT SHEET - 1,4-DIOXANE
At a Glance
* Flammable liquid and a fire hazard.
Potentially explosive if exposed to
light or air.
* Found at many federal facilities
because of its widespread use as a
stabilizer in chlorinated solvents,
paint strippers, greases, and
waxes.
* Short-lived in the atmosphere, may
leach readily from soil to ground
water, migrates rapidly in ground
water, and is relatively resistant to
biodegradation in the subsurface.
* Classified as "likely to be
carcinogenic to humans" by all
routes of exposure.
* Contact may cause eye and skin
irritation and burns, coughing, or
shortness of breath.
* No federal drinking water standards
have been established. Many
states and EPA regions have set
guidelines and action levels.
* Modifications to existing sample
preparation procedures may be
needed to achieve the increased
sensitivity needed for dioxane
detection. High-temperature
sample preparation techniques
improve the recovery of dioxane.
* Common treatment technologies
include advanced oxidation
processes and ex situ
bioremediation.
Introduction
This fact sheet, developed by the U.S. Environmental Protection Agency
(EPA) Federal Facilities Restoration and Reuse Office (FFRRO),
provides a brief summary of the contaminant 1,4-dioxane, including
physical and chemical properties; environmental and health impacts;
existing federal and state guidelines; detection and treatment methods;
and additional sources of information.
1,4-Dioxane is a probable carcinogen and has been found in ground
water at sites throughout the United States. The physical and chemical
properties and behavior of 1,4-dioxane create challenges for its
characterization and treatment. It is highly mobile and has not been
shown to readily biodegrade in the environment. This fact sheet is
intended for use by site managers faced with addressing 1,4-dioxane at
cleanup sites or in drinking water supplies and for those in a position to
consider whether 1,4-dioxane should be added to the analytical suite for
site investigations.
What is 1,4-Dioxane?
»> 1,4-Dioxane is a synthetic industrial chemical that is completely
miscible in water (EPA 2006).
»> Synonyms include dioxane, dioxan, p-dioxane, diethylene dioxide,
diethylene oxide, diethylene ether, and glycol ethylene ether
(Mohr2001).
»> 1,4-Dioxane is unstable at elevated temperatures and pressures and
is potentially explosive if exposed to light or air (Alexeeff 1998).
»> It is used as a stabilizer for chlorinated solvents such as 1,1,1-
trichloroethane (TCA); a solvent for impregnating cellulose acetate
membrane filters; a wetting and dispersing agent in textile
processes; and as a laboratory cryoscopic solvent for molecular
mass determinations (ATSDR 2007; EPA 2006).
»> It is used in many products, including paint strippers, dyes, greases,
varnishes, and waxes. 1,4-Dioxane is also found as an impurity in
antifreeze and aircraft deicing fluids and in some consumer products
(deodorants, shampoos, and cosmetics) (ATSDR 2007; EPA 2006;
Mohr2001).
»> 1,4-Dioxane is a likely contaminant at many federal facilities because
of its widespread use.
»> Residues may be present in manufactured food additives, 1,4-
dioxane-containing food packaging materials, or on food crops
treated with pesticides that contain 1,4-dioxane (such as, vine-
ripened tomatoes) (DHHS 2011).
»> It is also a by-product in the manufacture of polyethylene
terephthalate (PET) plastic and is used as a purifying agent in the
manufacture of Pharmaceuticals (Mohr2001).
United States
Environmental Protection Agency
Office of Solid Waste and
Emergency Response (5106P)
1
EPA 505-F-11-004
May 2012
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Technical Fact Sheet - 1,4-Dioxane
What is 1,4-Dioxane? (continued)
Exhibit 1: Physical and Chemical Properties of 1,4-Dioxane
(ATSDR2007; EPA IRIS 2010)
Property
CAS Number
Physical Description (physical state at room temperature)
Molecular weight (g/mol)
Water solubility (mg/L at 25°C)
Boiling point (°C)
Vapor pressure at 25°C (mm Hg)
Specific gravity
Octanol-water partition coefficient (log Kow)
Organic carbon partition coefficient (log Koc)
Henry's law constant (atm m3/mol)
000123-91-1
Flammable liquid with a faint, pleasant odor
88.10
Soluble in water
101. 1 "Cat 760 mm Hg
40
1.033
-0.27
1.23
4.80 X10'6
Notes: g/mol - grams per mole; mg/L - milligrams per liter; °C - degrees Celsius; mm Hg - millimeters of mercury;
atm m3/mol - atmosphere-cubic meters per mole.
What are the environmental impacts of 1,4-Dioxane?
1,4-Dioxane is typically found at solvent release
sites and PET manufacturing facilities (Mohr
2001).
It is short-lived in the atmosphere, with a 6- to 10-
hour half-life (Mohr2001). Breakdown products
include aldehydes and ketones.
It may migrate rapidly in ground water, ahead of
other contaminants, and does not volatilize rapidly
from surface water bodies (EPA 2006).
It is weakly retarded by sorption to soil particles
and may move rapidly from soil to ground water
(EPA 2006).
It is relatively resistant to biodegradation and does
not bioconcentrate in the food chain (ATSDR
2007; Mohr 2001).
It has been identified at 31 of the 1,689 sites on
EPA's National Priorities List (NPL); it may be
present (but samples were not analyzed for it) at
many other sites (ATSDR 2007).
What are the health effects of 1,4-Dioxane?
Potential exposure could occur during
production and use of 1,4-dioxane as a stabilizer
or solvent (DHHS 2011).
Exposure may occur through inhalation of
vapors, ingestion of contaminated food and
water, or dermal contact (DHHS 2011).
Inhalation is the most common route of human
exposure; it is also readily adsorbed through the
lungs, skin, and gastrointestinal tract.
Distribution is rapid and uniform in lung, liver,
kidney, spleen, colon, and skeletal muscle tissue
(ATSDR 2007).
Workers at industrial sites are at greatest risk of
repeated inhalation exposure (DHHS 2011).
Short-term exposure may result in irritation of
the eyes, nose, throat, and lungs; possible
drowsiness; vertigo; headache; and anorexia
(ATSDR 2007).
Chronic exposure may result in dermatitis,
eczema, drying and cracking of skin, and liver
and kidney damage (ATSDR 2007; EPA OSW
1996).
1,4-Dioxane is weakly genotoxic and
reproductive effects are unknown; however, a
developmental study on rats indicated that the
developing fetus may be a target of
toxicity (ATSDR 2007; EPA IRIS 2010).
EPA has classified 1,4-dioxane as "likely to be
carcinogenic to humans" by all routes of
exposure (EPA IRIS 2010).
The chronic oral reference dose (RfD) is 0.03
milligrams per kilogram per day (EPA IRIS
2010).
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Technical Fact Sheet - 1,4-Dioxane
Are there any federal and state standards and guidelines for 1,4-Dioxane?
Water Standards and Guidelines:
• 1,4-Dioxane may be regulated as hazardous
waste when used as a solvent stabilizer (EPA
OSW1996).
• No federal drinking water standards have been
established (DHHS 2011). However, a maximum
contaminant level (MCL) is not necessary to
determine a cleanup level.
• EPA Regions 3, 6, and 9 have calculated a
screening level of 6.1 micrograms per liter (ug/L)
for 1,4-dioxane in tap water, based on a 1 in 10
lifetime excess cancer risk. This screening level
is not enforceable but provides a useful gauge of
relative toxicity (EPA 2011).
• State regulators often use drinking water action
levels and health advisories to establish site
cleanup goals. Cleanup levels vary by state,
ranging from 3 to 85 ug/L in drinking water or
ground water. Only Colorado has established an
enforceable cleanup standard: facilities must
achieve a 6.1 ug/L level by March 2005 and a
3.2 ug/L level by March 2012 (CDPHE 2005).
Workplace Exposure Limits:
• The Occupational Safety and Health
Administration (OSHA) airborne permissible
exposure limit (PEL) is 360 milligrams per cubic
meter (mg/m3) or 100 mg/L
(NIOSH 2007; OSHA 1998).
• The American Conference of Governmental
Industrial Hygienists (ACGIH) threshold limit
value (TLV) for dermal exposure is 25 mg/L, and
the recommended airborne exposure limit is 20
mg/L averaged over an 8-hour work shift
(ACGIH 1998; EPA OSW 1996).
• The National Institute for Occupational Safety
and Health (NIOSH) has set 500 mg/L as the
concentration that is immediately dangerous to
life or health (IDLH) and recommended 1 mg/L
as the airborne exposure limit (NIOSH 2007).
Other Federal Standards and Guidelines:
• The Food and Drug Administration set 10 parts
per million (ppm) as the limit for 1-4-dioxane in
glycerides and polyglycerides for use in products
such as dietary supplements. FDA also surveys
raw material and products contaminated with
1,4-dioxane (ATSDR 2007).
• 1,4-Dioxane is exempted from tolerances for
pesticide chemicals in or on raw agricultural
commodities, and it has been classified as a
toxic inert ingredient of pesticide products
(EPA 2012).
• 1,4-Dioxane is listed as a hazardous air pollutant
under the Clean Air Act (CAA) (EPA 2012).
• A reportable quantity of 100 pounds has been
established under CERCLA (EPA 2012).
What detection and site characterization methods are available for
1,4-Dioxane?
As a result of the limitations in the analytical
methods to detect 1,4-dioxane, it has been difficult
to identify its occurrence in the environment.
Modifications to existing sample preparation
procedures may be needed to achieve increased
sensitivity for 1,4-dioxane detection (EPA 2006).
Conventional analytical methods produced
sensitivity levels that were about 100 times greater
for 1,4-dioxane as compared with those for volatile
organic compounds (VOCs) (Mohr2001).
High-temperature sample preparation techniques
improve the recovery of 1,4-dioxane. These
techniques include purging at elevated
temperature (SW-846 Method 5030C); equilibrium
headspace analysis (SW-846 Method 5021);
vacuum distillation (SW-846 Method 8261 A); and
azeotrophic distillation (SW-846 Method 5031)
(EPA 2000, 2006).
It is recommended that ground water samples be
analyzed for 1,4-dioxane where TCA is a known
contaminant.
What technologies are being used to treat 1,4-Dioxane?
Pump-and-treat (P&T) remediation is potentially
applicable when the ex situ treatment is tailored for
the unique properties of 1,4-dioxane
(EPA 2006).
Commercially available advanced oxidation
processes (AOP) using hydrogen peroxide with
ultraviolet (UV) light or ozone is used to treat 1,4-
dioxane (EPA 2006; EPA OSW 1996).
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Technical Fact Sheet - 1,4-Dioxane
What technologies are being used to treat 1,4-Dioxane? (continued)
Ex situ bioremediation using a fixed-film, moving-
bed biological treatment system is also used to
treat 1,4-dioxane (EPA 2006).
Phytoremediation is being explored as a means to
remove the compound from shallow ground water.
Research on hybrid poplars has demonstrated
their ability to take up and effectively degrade or
deactivate 1,4-dioxane (EPA 2001, EPA 2012).
Microbial degradation in engineered bioreactors
has been documented under enhanced conditions
or where selected strains of bacteria capable of
degrading 1,4-dioxane are cultured
(EPA 2006, 2010).
Photocatalysis has been shown to remove 1,4-
dioxane in aqueous solutions (Purifies ES Inc.
2006; Vescovietal. 2010).
Other in-well combined treatment technologies
being assessed include air sparging; soil vapor
extraction; and dynamic subsurface ground water
circulation (Odah et al. 2005).
Where can I find more information about 1,4-Dioxane?
Agency for Toxic Substances and Disease
Registry (ATSDR). 2007. "lexicological Profile for
1,4-Dioxane."
www.atsdr.cdc.gov/toxprofiles/tp187.pdf
Alexeeff, G. 1998. Office of Environmental Hazard
Assessment. Memorandum: 1,4-Dioxane Action
Level.
http://oehha.ca.gov/water/pals/pdf/PAL14DIOXAN.
Edf
American Conference of Governmental Industrial
Hygienists (ACGIH). 1998. Threshold Limit Values
(TLVs) for Chemical Substances and Physical
Agents Biological Exposure Indices for 1998.
Cincinnati, Ohio.
Colorado Department of Public Health and the
Environment (CDPHE). 2005. Regulation No 31.
http://water.epa.gov/scitech/swguidance/standards
/upload/2006 01 23 standards wqslibrary co re
Q31-20051231.pdf
International Agency for Research on Cancer
(IARC). 1999. "Re-Evaluation of Some Organic
Chemicals, Hydrazine and Hydrogen Peroxide."
Monographs on the Evaluation of Carcinogenic
Risk of Chemicals to Man. Volume 71. Pages 589
to 602.
Mohr, T.K.G. 2001. "Solvent Stabilizers White
Paper." Prepublication Copy. Santa Clara Valley
Water District of California. San Jose, California.
National Institute for Occupational Safety and
Health (NIOSH). 2007. "Pocket Guide to Chemical
Hazards." Cincinnati, Ohio. Page 120.
www.cdc.gov/niosh/docs/2005-149/pdfs/2005-
149.pdf
Occupational Safety and Health Administration
(OSHA). 1998. "Occupational Safety and Health
Standards, Toxic and Hazardous Substances." 29
Code of Federal Regulations 1910.1000.
Odah, M.M., R. Powell, and D.J. Riddle. 2005.
"ART in-well technology proves effective in
treating 1,4-Dioxane contamination." Remediation
Journal. Volume 15 (3), Pages 51 to 64.
Purifies ES Inc. 2006. Case History: 1,4 Dioxane
Remediation 1.
www.purifics.com/solutions/pdf/Case%20History%
20-%201,4-Dioxane%201 .pdf
U.S. Department of Health and Human Services
(DHHS). 2011. 1,4-Dioxane, CAS No. 123-91-1,
Report on Carcinogens, 12th Edition.
U.S. Environmental Protection Agency (EPA)
Office of Solid Waste (OSW). 1996. Solvents
Study. EPA 530-R-96-017, 52 pages.
EPA. 2000. "Method 8261. Volatile Organic
Compounds by Vacuum Distillation in Combination
with Gas Chromatography/Mass Spectroscopy
(VD/GC/MS)." In: SW-846 Draft Update IVB.
EPA. 2001. "Brownfields Technology Primer:
Selecting and Using Phytoremediation for Site
Cleanup." EPA 542-R-01-006.
EPA. 2006. "Treatment Technologies for 1,4-
Dioxane: Fundamentals and Field Applications."
EPA 542-R-06-009.
www.epa.gov/tio/download/remed/542r06009.pdf
EPA. 2012. "1,4 Dioxane" www.clu-in.org/
contaminantfocus/default.focus/sec/1,4-
Dioxane/cat/Overview/
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Technical Fact Sheet - 1,4-Dioxane
Where can I find more information about 1,4-Dioxane? (continued)
EPA. 2011. Regions 3, 6, and 9. Regional
Screening Levels Table.
www.epa.gov/reg3hwmd/risk/human/index.htm
EPA Integrated Risk Information System (IRIS).
2010. "1,4-Dioxane (CASRN 123-91-1)."
www.epa.gov/iris/subst/0326.htm
Vescovi T., H. Coleman, and R. Amal. 2010. "The
Effect of pH on UV-based advanced oxidation
technologies- 1,4-dioxane degradation." Journal of
Hazardous Materials. Volume 182. Pages 75 to
79.
Additional information on 1,4-dioxane can be found at www.cluin.org/dioxane.
If you have any guestions or comments on this fact sheet, please contact: Mary Cooke, FFRRO, by phone at
(703) 603-8712 or by email at cooke.maryt@epa.gov.
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