Untied States
Environmental Proteetion
Agency
® ERA
Fact Sheet: Final Third Drinking Water
Contaminant Candidate List (CCL 3)
EPA has published a final list of contaminants which may require regulation under the Safe
Drinking Water Act (SOWA).
This final Contaminant Candidate List 3 (CCL 3) includes 104 chemicals or chemical groups and
12 microbiological contaminants which are known or anticipated to occur in public water
systems. The list includes chemicals used in commerce, pesticides, waterborne pathogens,
disinfection byproducts, and biological toxins. The Agency evaluated approximately 7,500
chemicals and microbes and selected 116 candidates for the CCL 3 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. The draft CCL 3
was published in February 2008.
What contaminants are included on the CCL 3?
The chemicals and microbes are listed on the attached table.
Final Drinking Water Contaminant Candidate List 3
Chemical Contaminants
CASRN
630206
Common Name -
Registry Name
1,1,1,2-
Tetrachloroethane
Office of Water (4607M) EPA EPA 815F09001 September 2009 www.epa.gov/safewater
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75343
96184
106990
99650
123911
57910
71363
109864
107186
16655826
101779
30560191
75070
60355
34256821
187022113
184992444
107028
142363539
171262172
319846
62533
741582
100447
25013165
1 , 1 -Dichloroethane
1,2,3 -Trichloropropane
1,3 -Butadiene
1,3-Dinitrobenzene
1,4-Dioxane
17 alpha-Estradiol
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
Alachlor ethanesulfonic
acid (ESA)
Alachlor oxanilic acid
(OA)
alpha-
Hexachl orocy cl ohexan
e
Aniline
Bensulide
Benzyl chloride
Butylated
hydroxyanisole
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133062
14866683
74873
110429624
7440484
80159
NA
141662
55290647
60515
298044
330541
517099
474862
114078
50282
50271
53167
57636
13194484
107211
75218
96457
22224926
50000
7440564
74975
Captan
Chlorate
Chloromethane (Methyl
chloride)
Clethodim
Cobalt
Cumene hydroperoxide
Cyanotoxins
Dicrotophos
Dimethipin
Dimethoate
Disulfoton
Diuron
Equilenin
Equilin
Erythromycin
Estradiol (17-beta
estradiol)
Estriol
Estrone
Ethinyl Estradiol (17-
alpha Ethynyl
Estradiol)
Ethoprop
Ethylene glycol
Ethyl ene oxide
Ethylene thiourea
Fenamiphos
Formaldehyde
Germanium
Halon 1011
Office of Water (4607M) EPA EPA 815F09001 September 2009
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75456
110543
302012
72333
10265926
67561
74839
1634044
51218452
171118095
152019733
2212671
7439987
98953
55630
872504
55185
62759
621647
86306
930552
68224
(bromochloromethane)
HCFC-22
Hexane
Hydrazine
Mestranol
Methamidophos
Methanol
Methyl bromide
(Bromomethane)
Methyl tert-butyl ether
Metolachlor
Metolachlor
ethanesulfonic acid
(ESA)
Metolachlor oxanilic
acid (OA)
Molinate
Molybdenum
Nitrobenzene
Nitroglycerin
N-Methyl-2-
pyrrolidone
N-Nitrosodiethylamine
(NDEA)
N-
nitrosodimethylamine
(NDMA)
N-Nitroso-di-n-
propylamine (NDPA)
N-
Nitrosodiphenylamine
N-nitrosopyrrolidine
(NPYR)
Norethindrone (19-
Norethisterone)
Office of Water (4607M) EPA EPA 815F09001 September 2009
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103651
95534
75569
301122
42874033
14797730
1763231
335671
52645531
41198087
91225
121824
135988
7440246
107534963
112410238
13494809
13071799
56070167
59669260
23564058
26471625
78488
121448
76879
51796
7440622
50471448
n-Propy Ib enzene
o-Toluidine
Oxirane, methyl-
Oxydemeton-methyl
Oxyfluorfen
Perchlorate
Perfluorooctane
sulfonic acid (PFOS)
Perfluorooctanoic acid
(PFOA)
Permethrin
Profenofos
Quinoline
RDX
sec-Butylbenzene
Strontium
Tebuconazole
Tebufenozide
Tellurium
Terbufos
Terbufos sulfone
Thiodicarb
Thiophanate-methyl
Toluene diisocyanate
Tribufos
Triethylamine
Triphenyltin hydroxide
(TPTH)
Urethane
Vanadium
Vinclozolin
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137304
Microbial Contaminants
Ziram
Adenovirus
Caliciviruses
Campylobacter jejuni
Enterovirus
Escherichia coli (0157)
Helicobacter pylori
Hepatitis A virus
Legionella pneumophila
Mycobacterium avium
Naegleria fowler i
Salmonella enterica
Shigella sonnet
What approach did EPA use to list contaminants on the CCL?
In developing the CCL 3, the Agency implemented a different process from that used for CCL 1
and CCL 2. This new process builds on evaluations from previous CCLs and was based on
substantial expert input and recommendations from various groups, including the National
Academy of Science's National Research Council (NRC), the National Drinking Water Advisory
Council (NOWAC), and the Science Advisory Board (SAB).
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 disease through drinking water
exposure.
EPA used a multi-step CCL process to identify contaminants for inclusion on the CCL 3.
key steps EPA took to develop the CCL 3 include:
The
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.
Office of Water (4607M) EPA EPA 815F09001 September 2009
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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 discussed above. 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.
How did EPA consider public comments on the draft CCL 3?
EPA published the draft CCL 3 FR notice in February 2008. In this FR notice, EPA solicited
input from the public, and specifically requested comments on (1) the approach EPA used to
create the list; (2) contaminants on the list; and (3) specific contaminants such as
Pharmaceuticals, perfluorinated compounds, and microbes. EPA reviewed all comments
received on the draft CCL 3 and evaluated information provided by commenters in determining
which contaminants to include on the final CCL 3.
What changes were made from the draft CCL 3 to the final CCL 3?
Based on the Agency's review of data and information collected during the comment period and
new available data, the Agency made these changes from the draft to the final CCL 3:
• Removed 2 pesticides (ethion and nitrofen) because the registrations were cancelled
and available data indicates they are unlikely to appear in drinking water sources.
• Added 10 pharmaceuticals; one antibiotic (erythromycin) and nine hormones (17
alpha-estradiol, 17-beta estradiol, equilenin, equilin, estriol, estrone, ethinyl estradiol,
mestranol, and norethindrone) based on new health effects and occurrence data in
ambient water.
• Added 2 disinfection by-products (bromochloromethane (HalonlOl 1) and chlorate)
based on new health effects and occurrence data.
• Added perfluorooctane sulfonate (PFOS) based on new health effects and occurrence
data in public water systems.
• Removed 2 microbes (Vibrio cholerae and Entamoeba histolyticd) because the
Agency decided to only use waterborne disease outbreak data more recent than
January 1991.
• Added 3 microbes to the final CCL 3 (Mycobacterium avium, Enterovirus and
Adenovirus). Mycobacterium avium was added to the list based on the Agency's re-
evaluation of its health effects. Enterovirus and Adenovirus were added to the list
based on changes to the selection criteria and because the Agency used waterborne
disease outbreak data more recent than January 1991.
What happens to contaminants on the draft CCL 3?
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The purpose of the draft CCL 3 was to present the list of contaminants and seek comment on the
list and various aspects of its development. The Agency sought 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 were considered in determining the final CCL3.
What happens to contaminants on the final CCL 3?
EPA will evaluate all the contaminants on the CCL 3 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 encourage 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?
A regulatory determination is a formal decision on whether EPA should initiate a process to
develop a national primary drinking water regulation for a specific contaminant. The law
requires that EPA make regulatory determinations for at least five contaminants from the most
recent CCL every five years.
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 EPA 815F09001 September 2009 www.epa.gov/safewater
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