Fact Sheet: Fifth Contaminant Environmental Protection *""" Candidate List (CCL 5) EPA has published the Contaminant Candidate List 5 (CCL 5). The final CCL 5 includes 66 chemicals, 3 chemical groups and 12 microbial contaminants which are known or anticipated to occur in public water systems. The CCL 5 includes contaminants used in commerce, pesticides, waterborne pathogens, disinfection byproducts, and biological toxins. In developing the CCL 5, EPA implemented improvements to the CCL process to better identify, screen, and classify potential drinking water contaminants. These improvements resulted in a CCL 5 that can better support prioritization of contaminants for regulatory decisions and research efforts. Questions and Answers What is the drinking water Contaminant Candidate List? The drinking water Contaminant Candidate List (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 (SDWA). EPA uses the CCL to identify priority contaminants for regulatory decision making and information collection needs. How often is the CCL published? The SDWA, as amended in 1996, 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, the third CCL (CCL 3) in October 2009, and the fourth CCL (CCL 4) in November 2016. What contaminants are included on the CCL 5? The chemical and microbial contaminants included on CCL 5 are listed in the tables below. Final Drinking Water Contaminant Candidate List 5- Chemical Contaminants Chemical Name CASRN1 DTXSID2 1,2,3-Trichloropropane 96-18-4 DTXSID9021390 1,4-Dioxane 123-91-1 DTXSID4020533 17-alpha ethynyl estradiol 57-63-6 DTXSID5020576 2,4-Dinitrophenol 51-28-5 DTXSID0020523 2-Aminotoluene 95-53-4 DTXSID 1026164 oEPA Office of Water (4607M) EPA 815-F-22-005 October 2022 1 ------- Chemical Name CASRN1 DTXSID2 2-Hydroxyatrazine 2163-68-0 DTXSID6037807 6-Chloro-l,3,5-triazine-2,4-diamine 3397-62-4 DTXSID 1037806 Acephate 30560-19-1 DTXSID8023 846 Acrolein 107-02-8 DTXSID5020023 alpha-Hexachlorocyclohexane 319-84-6 DTXSID2020684 Anthraquinone 84-65-1 DTXSID3020095 Bensulide 741-58-2 DTXSID9032329 Bisphenol A 80-05-7 DTXSID7020182 Boron 7440-42-8 DTXSID3023922 Bromoxynil 1689-84-5 DTXSID3 022162 Carbaryl 63-25-2 DTXSID9020247 Carbendazim (MBC) 10605-21-7 DTXSID4024729 Chlordecone (Kepone) 143-50-0 DTXSID 1020770 Chlorpyrifos 2921-88-2 DTXSID4020458 Cobalt 7440-48-4 DTXSID 1031040 Cyanotoxins3 Multiple Multiple Deethylatrazine 6190-65-4 DTXSID5037494 Desisopropyl atrazine 1007-28-9 DTXSID0037495 Desvenlafaxine 93413-62-8 DTXSID40869118 Diazinon 333-41-5 DTXSID9020407 Dicrotophos 141-66-2 DTXSID9023914 Dieldrin 60-57-1 DTXSID9020453 Dimethoate 60-51-5 DTXSID7020479 Disinfection byproducts (DBPs)4 Multiple Multiple Diuron 330-54-1 DTXSID0020446 Ethalfluralin 55283-68-6 DTXSID8032386 Ethoprop 13194-48-4 DTXSID4032611 Fipronil 120068-37-3 DTXSID4034609 Fluconazole 86386-73-4 DTXSID3 020627 Flufenacet 142459-58-3 DTXSID2032552 Fluometuron 2164-17-2 DTXSID8020628 Iprodione 36734-19-7 DTXSID3024154 Lithium 7439-93-2 DTXSID5036761 Malathion 121-75-5 DTXSID4020791 Manganese 7439-96-5 DTXSID2024169 Methomyl 16752-77-5 DTXSID 1022267 Methyl tert-butyl ether (MTBE) 1634-04-4 DTXSID3020833 Methylmercury 22967-92-6 DTXSID9024198 Office of Water (4607M) EPA 815-F-22-005 October 2022 2 ------- Chemical Name CASRN1 DTXSID2 Molybdenum 7439-98-7 DTXSID 1024207 Nonylphenol 25154-52-3 DTXSID3021857 Norflurazon 27314-13-2 DTXSID8024234 Oxyfluorfen 42874-03-3 DTXSID7024241 Per- and polyfluoroalkyl substances (PFAS)5 Multiple Multiple Permethrin 52645-53-1 DTXSID8022292 Phorate 298-02-2 DTXSID4032459 Phosmet 732-11-6 DTXSID5024261 Phostebupirim 96182-53-5 DTXSID 1032482 Profenofos 41198-08-7 DTXSID3032464 Propachlor 1918-16-7 DTXSID4024274 Propanil 709-98-8 DTXSID8022111 Propargite 2312-35-8 DTXSID4024276 Propazine 139-40-2 DTXSID3021196 Propoxur 114-26-1 DTXSID7021948 Quinoline 91-22-5 DTXSID 1021798 Tebuconazole 107534-96-3 DTXSID9032113 Terbufos 13071-79-9 DTXSID2022254 Thiamethoxam 153719-23-4 DTXSID2034962 Tri-allate 2303-17-5 DTXSID5024344 Tribufos 78-48-8 DTXSID 1024174 Tributyl phosphate 126-73-8 DTXSID3021986 Trimethylbenzene (1,2,4-) 95-63-6 DTXSID6021402 Tris(2-chloroethyl) phosphate (TCEP) 115-96-8 DTXSID5021411 Tungsten 7440-33-7 DTXSID8052481 Vanadium 7440-62-2 DTXSID2040282 1 Chemical Abstracts Service Registry Number (CASRN) is a unique identifier assigned by the Chemical Abstracts Service (a division of the American Chemical Society) to every chemical substance (organic and inorganic compounds, polymers, elements, nuclear particles, etc.) in the open scientific literature. It contains up to 10 digits, separated by hyphens into three parts. 2 Distributed Structure Searchable Toxicity Substance Identifiers (DTXSID) is a unique substance identifier used in EPA's CompTox Chemicals database, where a substance can be any single chemical, mixture or polymer. 3 Toxins naturally produced and released by some species of cyanobacteria (previously known as "blue-green algae"). The group of cyanotoxins includes, but is not limited to: anatoxin-a, cylindrospermopsin, microcystins, and saxitoxin. 4 This group includes 23 unregulated DBPs. 5 For the purpose of CCL 5, the structural definition of per- and polyfluoroalkyl substances (PFAS) includes chemicals that contain at least one of these three structures (except for PFOA and PFOS which are already in the regulatory process): 1. R-(CF2)-CF(R')R", where both the CF2 and CF moieties are saturated carbons, and none of the R groups can be hydrogen 2. R-CF20CF2-R', where both the CF2 moieties are saturated carbons, and none of the R groups can be hydrogen 3. CF3C(CF3)RR', where all the carbons are saturated, and none of the R groups can be hydrogen Office of Water (4607M) EPA 815-F-22-005 October 2022 3 ------- Final Drinking Water Contaminant Candidate List 5- Microbial Contaminants Microbial Name Type of Microorganism Adenovirus Virus Caliciviruses Virus Campylobacter jejuni Bacteria Escherichia coli (0157) Bacteria Enteroviruses Virus Helicobacter pylori Bacteria Legionella pneumophila Bacteria Mycobacterium abscessus Bacteria Mycobacterium avium Bacteria Naegleria fowleri Protozoa Pseudomonas aeruginosa Bacteria Shigella sonnei Bacteria What approach did EPA use to list contaminants on the CCL 5? EPA considered the best available health effects information and occurrence data to evaluate contaminants. In selecting contaminants for the CCL 5, EPA: 1. Followed the stepwise process used in developing the CCL 3 and CCL 4, which was based on expert input and recommendations from the Science Advisory Board (SAB), National Research Council (NRC), and National Drinking Water Advisory Committee (NDWAC). This process consists of building a broad universe of contaminants, screening the universe of contaminants, and classifying the contaminants to select the CCL. 2. Implemented improvements to the CCL process to better identify, screen, and classify potential drinking water chemical contaminants for CCL 5. EPA's approach utilized the best available data to characterize the occurrence and adverse health risks a contaminant may pose from potential drinking water exposure. Office of Water (4607M) EPA 815-F-22-005 October 2022 4 ------- 3. Sought and evaluated nominations from the public for additional contaminants to consider in October 2018. 4. Evaluated any new available data for those contaminants with previous negative regulatory determinations from previous CCLs for potential inclusion on the CCL 5. 5. Considered public and Science Advisory Board (SAB) recommendations and evaluated the data and information provided by commenters in determining the Final CCL 5. How did EPA consider public comments on the Draft CCL 5? EPA published the Draft CCL 5 in & Federal Register (FR) notice on July 19, 2021. In this FR notice, EPA solicited input from the public and specifically requested comments on: (1) contaminants that EPA selected for the Draft CCL 5 and any supporting data that could assist with developing the Final CCL 5; (2) existing data that EPA obtained and evaluated for developing the Draft CCL 5; and (3) improvements that EPA implemented for developing the Draft CCL 5. EPA reviewed all the comments received on the Draft CCL 5 and evaluated information provided by commenters when finalizing the CCL 5 for publication. What changes were made from the Draft CCL 5 to the Final CCL 5? Based on EPA's review of data and information collected during the comment period and new data available, EPA made the following changes from the Draft to the Final CCL 5: • EPA updated the CCL 5 Technical Support documents to include recommendations from public comments and SAB recommendations. • EPA revised and expanded the definition for PFAS to include additional PFAS substructures such as PFAS that are ethers, highly branched, persistent in water, and known to occur in drinking water and/or source water. What happens to contaminants on the Draft CCL 5? The purpose of the Draft CCL 5 was to present the list of contaminants and seek comment on the list and the various aspects of its development. EPA sought comments on the process used to identify the Draft CCL 5, the data used in the process, and on the individual contaminants Office of Water (4607M) EPA 815-F-22-005 October 2022 ------- included on the Draft CCL 5. All comments submitted were considered in determining the Final CCL 5. What happens to contaminants on the Final CCL 5? EPA will evaluate all the contaminants on the CCL 5 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 a 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 Ifind more information about this notice and the CCL? For more information on the Fifth CCL, please visit the EPA website, https://www.epa.eov/ccl/contaminant-candidate4ist-5-ccl-5. For general information on the CCL, please visit EPA's website, https://www.epa.gov/ccl. Office of Water (4607M) EPA 815-F-22-005 October 2022 6 ------- |