United States
Environmental Protection
Agency
® EPA
Fact Sheet: Third Drinking Water
Contaminant Candidate List (CCL 3)
EPA is publishing a draft list of contaminants which may require regulation under the Safe
Drinking Water Act (SDWA) for public review and comment.
This draft CCL 3 includes 93 chemicals or chemical groups and 11 microbiological contaminants
which are known or anticipated to occur in public water systems. The list includes chemicals
used in commerce, pesticides, biological toxins, disinfection byproducts, and waterborne
pathogens. The Agency evaluated approximately 7,500 chemicals and microbes and selected
104 candidates for the Draft CCL3 that have the potential to present health risks through
drinking water exposure.
You can find more information on the CCL on EPA's website at
www.epa.gov/safewater/ccl/index.html
Questions and Answers
What is the drinking water CCL?
The drinking water CCL is a list developed by EPA that identifies priority contaminants for
regulatory decision making and information collection. The contaminants on the list are known
or anticipated to occur in public water systems and may impact public health. However, they are
currently unregulated by existing national primary drinking water regulations.
How often is the CCL published?
The Safe Drinking Water Act directs EPA to publish a CCL every five years. We published the
first CCL in March 1998. We published the second CCL in February 2005.
What contaminants are included on the CCL 3?
The chemicals and microbes are listed on the attached table.
Draft Drinking Water Contaminant Candidate List 3
Microbial Contaminants
Common Name - Registry Name
Caliciviruses
Campy lobacter jejuni
Entamoeba histolytica
Office of Water (4607M) EPA 815 F 08 001 February 2008 www.epa.gov/safewater
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Escherichia coll (0157)
Helicobacter pylori
Hepatitis A virus
Legionella pneumophila
Naegleriafow leri
Salmonella enterica
Shigella sonnet
Vibrio cholerae
Chemical Contaminants
Common Name - Registry Name
alpha-Hexachl orocy cl ohexane
1,1,1 ,2-Tetrachloroethane
1 , 1 -Dichloroethane
1,2,3-Trichloropropane
1,3 -Butadiene
1,3-Dinitrobenzene
1,4-Dioxane
1-Butanol
2-Methoxyethanol
2-Propen-l-ol
3 -Hydroxycarbofuran
4,4'-Methylenedianiline
Acephate
Acetaldehyde
Acetamide
Acetochlor
Acetochlor ethanesulfonic acid (ESA)
Acetochlor oxanilic acid (OA)
Acrolein
CASRN
319-84-6
630-20-6
75-34-3
96-18-4
106-99-0
99-65-0
123-91-1
71-36-3
109-86-4
107-18-6
16655-82-6
101-77-9
30560-19-1
75-07-0
60-35-5
34256-82-1
187022-11-3
184992-44-4
107-02-8
Office of Water (4607M) EPA 815 F 08 001 February 2008 www.epa.gov/safewater
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Common Name - Registry Name
Alachlor ethanesulfonic acid (ESA)
Alachlor oxanilic acid (OA)
Aniline
Bensulide
Benzyl chloride
Butylated hydroxyanisole
Captan
Chloromethane (Methyl chloride)
Clethodim
Cobalt
Cumene hydroperoxide
Cyanotoxins (3)
Dicrotophos
Dimethipin
Dimethoate
Disulfoton
Diuron
Ethion
Ethoprop
Ethylene glycol
Ethyl ene oxide
Ethylene thiourea
Fenamiphos
Formaldehyde
Germanium
HCFC-22
Hexane
Hydrazine
CASRN
142363-53-9
171262-17-2
62-53-3
741-58-2
100-44-7
25013-16-5
133-06-2
74-87-3
110429-62-4
7440-48-4
80-15-9
141-66-2
55290-64-7
60-51-5
298-04-4
330-54-1
563-12-2
13194-48-4
107-21-1
75-21-8
96-45-7
22224-92-6
50-00-0
7440-56-4
75-45-6
110-54-3
302-01-2
Office of Water (4607M) EPA815F08001 February 2008 www.epa.gov/safewater
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Common Name - Registry Name
Methamidophos
Methanol
Methyl bromide (Bromomethane)
Methyl tert-butyl ether
Metolachlor
Metolachlor ethanesulfonic acid
(ESA)
Metolachlor oxanilic acid (OA)
Molinate
Molybdenum
Nitrobenzene
Nitrofen
Nitroglycerin
N-Methyl-2-pyrrolidone
N-nitrosodiethylamine (NDEA)
N-nitrosodimethylamine (NDMA)
N-nitroso-di-n-propylamine (NDPA)
N-Nitrosodiphenylamine
N-nitrosopyrrolidine (NPYR)
n-Propy Ib enzene
o-Toluidine
Oxirane, methyl-
Oxydemeton-methyl
Oxyfluorfen
Perchlorate
Permethrin
PFOA (perfluorooctanoic acid)
Profenofos
Quinoline
CASRN
10265-92-6
67-56-1
74-83-9
1634-04-4
51218-45-2
171118-09-5
152019-73-3
2212-67-1
7439-98-7
98-95-3
1836-75-5
55-63-0
872-50-4
55-18-5
62-75-9
621-64-7
86-30-6
930-55-2
103-65-1
95-53-4
75-56-9
301-12-2
42874-03-3
14797.73.0
52645-53-1
335-67-1
41198-08-7
91-22-5
Office of Water (4607M) EPA 815 F 08 001 February 2008 www.epa.gov/safewater
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Common Name - Registry Name
RDX(Hexahydro-l,3,5-trinitro-l,3,5-
triazine)
sec-Butylbenzene
Strontium
Tebuconazole
Tebufenozide
Tellurium
Terbufos
Terbufos sulfone
Thiodicarb
Thi ophanate-methy 1
Toluene diisocyanate
Tribufos
Triethylamine
Triphenyltin hydroxide (TPTH)
Urethane
Vanadium
Vinclozolin
Ziram
CASRN
121-82-4
135-98-8
7440-24-6
107534-96-3
112410-23-8
13494-80-9
13071-79-9
56070-16-7
59669-26-0
23564-05-8
26471-62-5
78-48-8
121-44-8
76-87-9
51-79-6
7440-62-2
50471-44-8
137-30-4
What approach did EPA use to list contaminants on the CCL?
In developing the Draft CCL 3, the Agency implemented a different process from that used for
CCL 1 and CCL 2. This new process builds on evaluations used for previous CCLs and was
based on substantial expert input and recommendations from the National Academy of Science's
National Research Council (NRC), the National Drinking Water Advisory Council (NOWAC),
and other groups.
In developing the Draft CCL 3, the Agency considered the best available health effects and
occurrence data and information to evaluate unregulated contaminants. EPA evaluated data for
chemicals identified in Superfund, registered pesticides, chemicals detected in drinking water
or source waters, chemicals released to the environment, or high production commercial
chemicals. The Agency also evaluated human pathogens for their potential to cause waterborne
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disease through drinking water exposure.
EPA used a multi-step CCL process to identify contaminants for inclusion on the Draft CCL 3.
The key steps EPA took to develop the Draft CCL 3 include:
1) Identifying a broad universe of potential drinking water contaminants (called the
"CCL Universe"). EPA evaluated 284 data sources that may identify potential chemical
and microbial contaminants and selected a set of approximately 7,500 contaminants from
these data sources for initial consideration.
2) Applying screening criteria to the CCL universe to identify those contaminants that
should be further evaluated (the preliminary CCL or PCCL) based on a contaminant's
potential to occur in public water systems and the potential for public health concern.
3) Identifying contaminants from the PCCL to include on the CCL based on more detailed
evaluation of occurrence and health effects and expert judgment applied in a transparent
reproducible manner.
4) Incorporating public input and expert review in the CCL process.
EPA sought public input by asking for nominations of contaminants to consider for the CCL in
October 2006 and incorporated these nominations into the three key steps already discussed.
EPA also convened several expert panels to obtain review and input on the processes used to
identify the draft CCL and the CCL 3 itself.
What happens to contaminants on the Draft CCL 3?
The purpose of the draft CCL 3 is to present the list of contaminants and seek comment on the
list and various aspects of its development. The Agency is requesting comments on the process
used to identify the Draft CCL 3, the data used in the process, and on the individual
contaminants included in the CCL 3. All comments submitted will be considered in determining
the final CCL 3, as well as in the development of future CCLs.
What happens to contaminants on the Final CCL 3?
EPA will evaluate all the contaminants on the CCL to determine which contaminants have
sufficient information to allow the Agency to make a regulatory determination. For those
contaminants that lack sufficient information, EPA will work with research institutions to
identify and conduct research to provide the information needed to determine whether to regulate
the contaminant.
Does the CCL impose any requirements on public water systems?
No. Publishing the CCL does not impose any requirements on public water systems. If EPA
decided to regulate a contaminant on the list in the future, the Agency would start a separate
rulemaking process with opportunity for public comment.
What is a regulatory determination?
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A regulatory determination is a formal decision on whether we should initiate a process to
develop a national primary drinking water regulation for a specific contaminant. The law
requires that we make regulatory determinations for at least five contaminants from the most
recent CCL every five years.
In July 2003, EPA announced its final regulatory determinations for a subset of nine
contaminants from the first CCL. EPA had sufficient health and occurrence information to make
the determination not to regulate Acanthamoeba, aldrin, dieldrin, hexachlorobutadiene,
manganese, metribuzin, naphthalene, sodium or sulfate. These nine contaminants were not
carried forward to the second CCL (or CCL 2 published in 2005).
In May 2007, EPA announced its preliminary determinations for 11 contaminants listed on the
second CCL and asked for public comment. EPA had sufficient health and occurrence
information to make the determination not to regulate boron, the dacthal mono- and di-acid
degradates, l,l-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), 1,3-dichloropropene (Telone),
2,4-dinitrotoluene, 2,6-dinitrotoluene, s-ethyl propylthiocarbamate (EPTC), fonofos, terbacil or
1,1,2,2-tetrachloroethane. We plan to notify the public of the final regulatory determinations in
2008.
Where can I find more information about this notice and the CCL?
For information on the third CCL 3, please visit the EPA internet website,
www.epa.gov/safewater/ccl/ccl3.html. For general information on drinking water, please visit
the EPA Safewater website at www.epa.gov/safewater or contact the Safe Drinking Water
Hotline at 1-800-426-4791. Local or international calls can reach the Hotline at 703-412-3330.
The Safe Drinking Water Hotline is open Monday through Friday, excluding legal holidays,
from 10:00 a.m. to 4:00 p.m. Eastern time.
Office of Water (4607M) EPA 815 F 08 001 February 2008 www.epa.gov/safewater
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