v>EPA
United States
protection Fact sheet: Drinking Water Contaminant
Candidate List 4 - Draft
EPA is publishing a draft list of contaminants that may require regulation in the future, in
accordance with the Safe Drinking Water Act.
The Drinking Water Contaminant Candidate List 4 - Draft (CCL 4) includes 100 chemicals or
chemical groups and 12 microbial contaminants that are known or anticipated to occur in public
water systems. The list includes, among others, chemicals used in commerce, pesticides,
biological toxins, disinfection byproducts, pharmaceuticals and waterborne pathogens. The
agency is requesting comments on the chemical and microbial contaminants included on the
Draft CCL 4 and suggestions for improvements to the process for the agency to consider for
future CCLs. The agency is also consulting with the Science Advisory Board (SAB) on the Draft
CCL 4. The agency will evaluate and consider all public comments and recommendations
received from the SAB in developing the Final CCL 4.
To submit comments on the Draft CCL 4, please follow the instructions for the 60-day comment
period provided in the of Federal Register Notice.
You can find more information on the CCL on the EPA's Website at: ^^^www2^a^ovic^.
Frequently Asked Questions
What is the drinking water CCL?
The drinking water CCL is a list of contaminants that are currently not subject to any proposed
or promulgated national primary drinking water regulations, but are known or anticipated to
occur in public water systems. Contaminants listed on the CCL may require future regulation
under the Safe Drinking Water Act (SOWA). EPA uses the CCL to identify priority
contaminants for regulatory decision making and information and collection (research) needs.
How often is the CCL published?
The SDWA directs EPA to publish a CCL every five years. The agency published the first CCL
(CCL 1) in March 1998, the second CCL (CCL 2) in February 2005 and the third CCL (CCL 3)
in October 2009.
Office of Water (4607M) EPA 815-F-15-001 January 2015
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Does the CCL impose any requirements on public water systems?
No. Publication of the CCL does not impose any requirements on public water systems. If EPA
decides to regulate a contaminant on the list in the future, the agency will start a separate
rulemaking process with opportunity for public comment.
What approach did EPA use to list contaminants on the Draft CCL 4?
The CCL 4 evaluation and selection process includes a three-pronged approach:
1) Carrying forward CCL 3 contaminants (except those with regulatory determinations).
2) Seeking and evaluating nominations from the public for additional contaminants to be
considered.
3) Evaluating any new available data for those contaminants with previous negative
regulatory determinations from CCL 1 or CCL 2 for potential inclusion on the CCL 4.
In May 2012, EPA sought public input by requesting nominations of contaminants to be
considered for inclusion on the CCL 4. The agency evaluated the nominated contaminants and
contaminants with previous negative regulatory determinations utilizing the best available health
effects and occurrence data and the same process for screening and scoring contaminants that
was used for CCL 3. The agency reviewed the data provided by the nominators and collected
additional data for the nominated contaminants and contaminants with previous negative
regulatory determinations.
What changes did EPA make from the Final CCL 3 to the Draft CCL 4?
Based on the agency's review of the best available health effects and occurrence data, EPA made
these changes to the list:
• Added two nominated contaminants (manganese and nonylphenol).
• Removed perchlorate because the agency made a positive regulatory determination in
2011.
• Removed five contaminants with preliminary regulatory determinations. As part of
the third Regulatory Determination (RD3) process, in October 2014, the agency made
preliminary determinations to not regulate four contaminants (1,3-dinitrobenzene;
dimethoate; terbufos and terbufos sulfone) and to regulate one contaminant
(strontium) listed on CCL 3. These five contaminants are being removed from the
Draft CCL 4, pending publication of the final RD3. For more information on the
preliminary regulatory determinations, please see: http7/www2.epa.gov/ccl.
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What happens to contaminants on the Final CCL 4?
After the Final CCL 4 is published, SDWA requires EPA to determine whether or not to regulate
at least five contaminants from the list in a separate process called Regulatory
Determination. The agency will compile and evaluate additional data on the CCL 4 contaminants
and determine which ones have sufficient information to be evaluated against the three criteria
listed in SDWA for making a regulatory determination. The agency will make regulatory
determinations for the CCL 4 contaminants that have sufficient data, and continue to collect
information, conduct and support research and/or find avenues to fill data and information gaps
for contaminants that lack sufficient information.
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
(SDWA) requires the agency to make regulatory determinations for at least five contaminants
from the most recent CCL within five years after the completion of the previous round of
regulatory determinations. To see the list of regulatory determinations for the previous CCLs,
please go to: ht^//www2.epa.gov/cgl
Where can I fend more information about this notice and the CCL?
For information on the CCL 4, please visit the EPA website,
http^//w\^^ For general information on drinking
water, please visit the EPA drinking water website at http://water.epa.gov/drink/ 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 Hotline is open Monday through Friday, excluding federal
holidays, from 10:00 a.m. to 4:00 p.m., eastern time.
What contaminants are included on the Draft CCL 4?
The chemicals and microbes are listed on the attached table.
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Chemicals
Draft Drinking Water Contaminant Candidate List 4
Substance Name
1 ,1 -Diochloroethene
1,1,1,2-
Tetrachloroethane
1 ,2,3-Trichloropropane
1 ,3-Butadiene
1 ,4-Dioxane
1 7 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
CASRN
75-34-3
630-20-6
96-18-4
106-99-0
123-91-1
57-91-0
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
Use
It is an industrial solvent and an intermediate in the synthesis
of other compounds.
It is an industrial solvent and used in the synthesis of other
chlorinated compounds.
It is an industrial solvent, cleaning and degreasing agent as
well as an intermediate in the synthesis of the other
compounds.
It is used in the production of rubber and plastics.
It is used as a solvent or solvent stabilizer in the
manufacturing and processing of paper, cotton, textile
products, automotive coolant, cosmetics and shampoos.
It is an estrogenic hormone found in some Pharmaceuticals.
It is a solvent used in production of other chemicals and
compounds. It is present in a number of commercial products
such as perfumes.
It is used in a number of consumer products, such as
synthetic cosmetics, perfumes, fragrances, hair preparations
and skin lotions.
It is used in the production of other chemicals.
It is a pesticide degradate, the parent, carbofuran, is used as
an insecticide.
It is used in the production of polyurethane foams, glues,
rubber and spandex fiber.
It is an insecticide.
It is a disinfection byproduct from ozonation; it is used in the
production of other chemicals.
It is used as a solvent and plasticizer.
It is an herbicide for weed control on agricultural crops.
Acetochlor ESA is an environmental degradate of acetochlor.
Acetochlor OA is an environmental degradate of acetochlor.
It is used as an aquatic herbicide, rodenticide and industrial
chemical.
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Substance Name
Alachlor ethanesulfonic
acid (ESA)
Alachlor oxanilic acid
(OA)
alpha-
Hexachlorocyclohexane
Aniline
Sensulide
Senzyl chloride
Sutylated
lydroxyanisole
Captan
Chlorate
Chloromethane (Methyl
chloride)
Clethodim
Cobalt
Cumene hydroperoxide
Cyanotoxins
Dicrotophos
Dimethipin
Disulfoton
Diuron
iquilenin
iquilin
irythromycin
CASRN
142363-53-9
171262-17-2
319-84-6
62-53-3
741-58-2
100-44-7
25013-16-5
133-06-2
14866-68-3
74-87-3
110429-62-4
7440-48-4
80-15-9
141-66-2
55290-64-7
298-04-4
330-54-1
517-09-9
474-86-2
114-07-8
Use
Alachlor ESA is an environmental degradate of the pesticide
alachlor (an herbicide for weed control on agricultural crops).
Alachlor OA is an environmental degradate of alachlor.
It is a component of benzene hexachloride (BHC) and was
formerly used as an insecticide.
It is used as an industrial chemical, as a solvent, in the
synthesis of explosives, rubber products and in isocyanates.
It is an herbicide.
It is used in the production of other substances, such as
plastics, dyes, lubricants, gasoline and Pharmaceuticals.
It is used as a food additive (antioxidant).
It is a fungicide.
Chlorate compounds are used in agriculture as defoliants or
desiccants and may occur in drinking water because of use of
disinfectants such as chlorine dioxide and hypochlorites.
It is used as a foaming agent and in the production of other
substances.
It is an herbicide.
It is a naturally-occurring element and was formerly used as
cobaltous chloride in medicines and as a germicide. It is a
part of the vitamin Bl 2 molecule
It is used as a catalyst in the production of other substances.
Toxins naturally produced and released by cyanobacteria
("blue-green algae"). Various studies suggest three
cyanotoxins for consideration: Anatoxin-a,
Cylindrospermopsin and Microcystin-LR.
It is an insecticide.
It is an herbicide and plant growth regulator.
It is an insecticide.
It is an herbicide.
It is an estrogenic hormone used in hormone replacement
therapy.
It is an estrogenic hormone used in hormone replacement
therapy.
It is used an antibiotic.
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Substance Name
Estradiol (17-beta
estradiol)
Estriol
Estrone
Ethinyl estradiol (1 7-
alpha ethynyl estradiol)
Ethoprop
Ethylene glycol
Ethylene oxide
Ethylene thiourea
Fenamiphos
Formaldehyde
Germanium
HCFC-22
Halon 1011
(bromochloromethane)
Hexane
Hydrazine
Manganese
Mestranol
CASRN
50-28-2
50-27-1
53-16-7
57-63-6
13194-48-4
107-21-1
75-21-8
96-45-7
22224-92-6
50-00-0
7440-56-4
75-45-6
74-97-5
110-54-3
302-01-2
7439-96-5
72-33-3
Use
t is an isomer of estradiol found in some Pharmaceuticals.
t is a weak estrogenic hormone used in veterinary
Pharmaceuticals.
t is a precursor of estradiol used in veterinary and human
Pharmaceuticals.
t is an estrogenic hormone used in veterinary and human
oral contraceptives.
t is an insecticide.
t is used as antifreeze, in textile manufacturing and is a
cancelled pesticide.
t is a fungicidal and insecticidal fumigant.
t is used in the production of other substances, such as for
vulcanizing polychloroprene (neoprene) and polyacrylate
rubbers and is a metabolite of the pesticide maneb.
t is an insecticide.
t is an ozonation disinfection byproduct, can occur naturally
and has been used as a fungicide.
t is a naturally-occurring element and is commonly found as
germanium dioxide in phosphors, transistors and diodes, and
n electroplating. In some cases it has been sold as a dietary
supplement.
t is used as a refrigerant, as a low-temperature solvent, and
n fluorocarbon resins, especially in tetrafluoroethylene
polymers.
t is used as a fire-extinguishing fluid and to suppress
explosions, as well as a solvent in the manufacturing of some
pesticides. May also occur as a disinfection by-product in
drinking water.
t is a component of gasoline and used as a solvent.
t is used as an ingredient in the production of other
substances, such as rocket propellants. It is also used in the
production of plastics.
t is a naturally-occurring element used in a variety of
applications including use in steel production to improve
lardness, stiffness and strength. It is an essential nutrient
bund in vitamin/mineral supplement and in fortified foods.
t is a precursor to ethinylestradiol used in veterinary and
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Substance Name
Methamidophos
Methanol
Methyl bromide
(bromomethane)
Methyl tert-butyl ether
(MTBE)
Metolachlor
Metolachlor
ethanesulfonic acid
(ESA)
Metolachlor oxanilic
acid (OA)
Molinate
Molybdenum
Nitrobenzene
Nitroglycerin
N-Methyl-2-
pyrrolidone
N-Nitrosodiethylamine
(NDEA)
N-
Nitrosodimethylamine
(NDMA)
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
55-63-0
872-50-4
55-18-5
62-75-9
Use
luman Pharmaceuticals.
t is an insecticide.
t is used as an industrial solvent, a gasoline additive and as
an anti-freeze ingredient.
t has been used as a fumigant and fungicide.
t is used as an octane booster in gasoline, in the
manufacturing of isobutene and as an extraction solvent.
t is an herbicide for weed control on agricultural crops.
Metolachlor ESA is an environmental degradate of
metolachlor.
Metolachlor OA is an environmental degradate of
metolachlor.
t is an herbicide.
t is a naturally-occurring element and is commonly found as
molybdenum trioxide. It is used as a steel alloy. It is an
essential dietary nutrient found in foods and nutritional
supplements.
t is used in the production of aniline, and also as a solvent in
the manufacturing of paints, shoe polishes, floor polishes,
metal polishes, explosives, dyes, pesticides and drugs (such
as acetaminophen).,
t is used in the production of explosives and in rocket
jropellants. It is also a pharmaceutical for the treatment of
angina.
t is a solvent in the chemical industry and is used in the
brmulation of Pharmaceuticals for oral and dermal delivery.
t is a nitrosamine used as an additive in gasoline and in
ubricants, as an antioxidant and as a stabilizer in plastics. It
s formed in cured foods and during high temperature
cooking of meats and fish, and may be a disinfection
Byproduct.
t was formerly used in the production of rocket fuels, anti-
oxidants and softeners for copolymers. It is formed in cured
bods and during high temperature cooking. It may be a
eachate from rubber gaskets and fittings and may form as a
disinfection byproduct.
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Substance Name
N-Nitroso-di-n-
propylamine (NDPA)
N-
Nitrosodiphenylamine
N-Nitrosopyrrolidine
(NPYR)
Nonylphenol
Norethindrone (1 9-
Norethisterone)
n-Propyl benzene
o-Toluidine
Oxirane, methyl
Oxydemeton-methyl
Oxyfluorfen
Perfluorooctane-
sulfonic acid (PFOS)
Perfluorooctanoic acid
(PFOA)
Permethrin
Profenofos
Quinoline
RDX(Hexahydro-l,3,5-
trinitro-1 ,3,5-triazine)
CASRN
621-64-7
86-30-6
930-55-2
25154-52-3
68-22-4
103-65-1
95-53-4
75-56-9
301-12-2
42874-03-3
1763-23-1
335-67-1
52645-53-1
41198-08-7
91-22-5
121-82-4
Use
t is formed in cured foods and during high temperature
cooking of meats and fish and may be a disinfection
Byproduct. It is a contaminant in dinitrofluralin herbicides.
t is used in the vulcanization of rubber and as an inhibitor of
jolymerization in the production of polystyrene. It may be a
disinfection byproduct.
t is used in rubber production. It is formed in cured foods
and during high temperature cooking of meats and fish and
may be a disinfection byproduct.
t is used in the preparation of lubricating oil additives,
resins, plasticizers and antioxidants for plastic and rubber. It
s an environmental degradate from nonylphenol ethoxylate
surfactants found in detergents and used in the treatment of
textiles.
t is a synthetic hormone used in oral contraceptives and for
lormone replacement therapy.
t is a constituent of asphalt and naptha and used in the
manufacture of methyl styrene. It is a solvent for printing and
dying of textiles.
t is used in the production of dyes, rubber, Pharmaceuticals
and pesticides.
t is an industrial chemical used in the production of other
substances. It is a registered pesticide.
t is an insecticide.
t is an herbicide.
t is used in firefighting foams. It has various surfactant uses
and it was used to provide soil, water and oil resistance for
upholstered furniture and carpets. Many of these uses are
jeing phased out by U.S. manufacturers.
t is used in the manufacturing of coatings, which provide
non-stick surfaces on cookware, and in the manufacture of
waterproof, breathable membranes for clothing.
t is an insecticide.
t is an insecticide and an acaricide.
t is a component of coal tars and used in the production of
other substances, and as a pharmaceutical (anti-malarial).
t is an explosive.
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Substance Name
sec-Butylbenzene
Tebuconazole
Tebufenozide
Tellurium
Thiodicarb
Thiophanate-methyl
Toluene diisocyanate
Tribufos
Triethylamine
Triphenyltin hydroxide
(TPTH)
Urethane
Vanadium
Vinclozolin
Ziram
CASRN
135-98-8
107534-96-3
112410-23-8
13494-80-9
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
Use
It is used as a solvent for coatings in organic synthesis, as a
plasticizer and in surfactants.
It is a fungicide.
It is an insecticide.
It is a naturally-occurring element and is commonly used as
sodium tellurite in bacteriology and medicine.
It is an insecticide.
It is a fungicide.
It is used in the manufacturing of plastics.
It is an insecticide and used as a cotton defoliant.
It is used in the production of other substances, as a
stabilizer in herbicides and pesticides, in consumer products,
in photographic chemicals and in carpet cleaners.
It is a pesticide.
It is a paint and coating ingredient (polyurethanes).
It is a naturally-occurring element. Vanadium pentoxide is a
catalyst for the production of other substances catalyst. It is
sometimes an ingredient in mineral supplements but is not
classified as an essential nutrient
It is a fungicide.
It is a fungicide.
Microbes
Microbial Contaminant
Name
Adenovirus
Calicivi ruses
Campylobacterjejuni
Enterovirus
Escherichia co//(01 57)
Type
Virus
Virus (includes
Norovirus)
Bacteria
Viruses
including
poliovi ruses,
coxsackievi ruses
and echoviruses
Bacteria
Diseases and Infections
Respiratory illness and occasionally gastrointestinal
illness.
Mild self-limiting gastrointestinal illness.
Mild self-limiting gastrointestinal illness.
Mild respiratory illness.
Gastrointestinal illness and kidney failure.
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Microbial Contaminant
Name
Helicobacter pylori
Hepatitis A virus
Legionella pneumophila
Myco bacterium avium
Naegleria fowleri
Salmonella enterica
Shigella sonnei
Type
Bacteria
Virus
Bacteria
Bacteria
Protozoan
Bacteria
Bacteria
Diseases and Infections
Found in the environment capable of colonizing human
gut, which can cause ulcers and cancer.
Liver disease and jaundice.
Found in the environment including hot water systems
causing lung diseases when inhaled.
Lung infection in those with underlying lung disease, and
disseminated infection in the severely immuno-
compromised.
Parasite found in shallow, warm surface and ground
water, causing primary amebic meningoencephalitis.
Mild self-limiting gastrointestinal illness.
Mild self-limiting gastrointestinal illness and bloody
diarrhea.
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