Skip to main content
U.S. flag

An official website of the United States government

Here’s how you know

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

HTTPS

Secure .gov websites use HTTPS
A lock (LockA locked padlock) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

    • Environmental Topics
    • Air
    • Bed Bugs
    • Cancer
    • Chemicals, Toxics, and Pesticide
    • Emergency Response
    • Environmental Information by Location
    • Health
    • Land, Waste, and Cleanup
    • Lead
    • Mold
    • Radon
    • Research
    • Science Topics
    • Water Topics
    • A-Z Topic Index
    • Laws & Regulations
    • By Business Sector
    • By Topic
    • Compliance
    • Enforcement
    • Laws and Executive Orders
    • Regulations
    • Report a Violation
    • Environmental Violations
    • Fraud, Waste or Abuse
    • About EPA
    • Our Mission and What We Do
    • Headquarters Offices
    • Regional Offices
    • Labs and Research Centers
    • Planning, Budget, and Results
    • Organization Chart
    • EPA History

Breadcrumb

  1. Home
  2. Contaminant Candidate List (CCL) and Regulatory Determination

CCL 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 DTXSID1026164
2-Hydroxyatrazine 2163-68-0 DTXSID6037807
6-Chloro-1,3,5-triazine-2,4-diamine 3397-62-4 DTXSID1037806
Acephate 30560-19-1 DTXSID8023846
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 DTXSID3022162
Carbaryl 63-25-2 DTXSID9020247
Carbendazim (MBC) 10605-21-7 DTXSID4024729
Chlordecone (Kepone) 143-50-0 DTXSID1020770
Chlorpyrifos 2921-88-2 DTXSID4020458
Cobalt 7440-48-4 DTXSID1031040
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 DTXSID3020627
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 DTXSID1022267
Methyl tert-butyl ether (MTBE) 1634-04-4 DTXSID3020833
Methylmercury 22967-92-6 DTXSID9024198
Molybdenum 7439-98-7 DTXSID1024207
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 DTXSID1032482
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 DTXSID1021798
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 DTXSID1024174
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-CF2OCF2-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

Contaminant Candidate List (CCL) and Regulatory Determination

  • Basic Information
  • Draft Contaminant Candidate List 6
  • Contaminant Candidate List 5
  • Contaminant Candidate List 4
  • Contaminant Candidate List 3
  • Contaminant Candidate List 2
  • Contaminant Candidate List 1
  • Regulatory Determination 5
  • Regulatory Determination 4
  • Regulatory Determination 3
  • Regulatory Determination 2
  • Regulatory Determination 1
  • Types of Drinking Water Contaminants
Contact Us About the CCL and Regulatory Determinations
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on October 3, 2024
  • Assistance
  • Spanish
  • Arabic
  • Chinese (simplified)
  • Chinese (traditional)
  • French
  • Haitian Creole
  • Korean
  • Portuguese
  • Russian
  • Tagalog
  • Vietnamese
United States Environmental Protection Agency

Discover.

  • Accessibility Statement
  • Budget & Performance
  • Contracting
  • EPA www Web Snapshot
  • Grants
  • No FEAR Act Data
  • Plain Writing
  • Privacy
  • Privacy and Security Notice

Connect.

  • Data
  • Inspector General
  • Jobs
  • Newsroom
  • Regulations.gov
  • Subscribe
  • USA.gov
  • White House

Ask.

  • Contact EPA
  • EPA Disclaimers
  • Hotlines
  • FOIA Requests
  • Frequent Questions
  • Site Feedback

Follow.