Draft Fifth Contaminant Candidate List (CCL 5) Published By EPA
The Draft Fifth Contaminant Candidate List (CCL 5) was issued by the Environmental Protection Agency (EPA) on July 19, 2021. Here we review the CCL and take a look at the chemicals and other substances on the most recent version.
CCL 5 Chemical Substances
The presence of harmful substances in drinking water is a topic of ongoing public concern, and a diverse range of drinking water contaminant types exists. These include chemical, biological, physical, and radiological contaminants. Of all possible contaminant types, only a relatively small number of them are included in the CCL.
Since its initial development more than two decades ago, the CCL has undergone several iterations. The Draft CCL 5 represents the most recent version. Containing contaminants present in water systems, CCL chemicals and other substances are not covered by existing EPA regulations.
Sixty-six chemicals are included on the Draft CCL 5:
| Substance Name | CAS Number |
|---|---|
| 1,2,3-Trichloropropane | 96-18-4 |
| 1,4-Dioxane | 123-91-1 |
| 17-alpha ethynyl estradiol | 57-63-6 |
| 2,4-Dinitrophenol | 51-28-5 |
| 2-Aminotoluene | 95-53-4 |
| 2-Hydroxyatrazine | 2163-68-0 |
| 4-Nonylphenol (all isomers) | 25154-52-3 |
| 6-Chloro-1,3,5-triazine-2,4-diamine | 3397-62-4 |
| Acephate | 30560-19-1 |
| Acrolein | 107-02-8 |
| alpha-Hexachlorocyclohexane (alpha-HCH) | 319-84-6 |
| Anthraquinone | 84-65-1 |
| Bensulide | 741-58-2 |
| Bisphenol A | 80-05-7 |
| Boron | 7440-42-8 |
| Bromoxynil | 1689-84-5 |
| Carbaryl | 63-25-2 |
| Carbendazim (MBC) | 10605-21-7 |
| Chlordecone (Kepone) | 143-50-0 |
| Chlorpyrifos | 2921-88-2 |
| Cobalt | 7440-48-4 |
| Cyanotoxins | Multiple |
| Deethylatrazine | 6190-65-4 |
| Desisopropyl atrazine | 1007-28-9 |
| Desvenlafaxine | 93413-62-8 |
| Diazinon | 333-41-5 |
| Dicrotophos | 141-66-2 |
| Dieldrin | 60-57-1 |
| Dimethoate | 60-51-5 |
| Disinfection byproducts (DBPs) | Multiple |
| Diuron | 330-54-1 |
| Ethalfluralin | 55283-68-6 |
| Ethoprop | 13194-48-4 |
| Fipronil | 120068-37-3 |
| Fluconazole | 86386-73-4 |
| Flufenacet | 142459-58-3 |
| Fluometuron | 2164-17-2 |
| Iprodione | 36734-19-7 |
| Lithium | 7439-93-2 |
| Malathion | 121-75-5 |
| Manganese | 7439-96-5 |
| Methomyl | 16752-77-5 |
| Methyl tert-butyl ether (MTBE) | 1634-04-4 |
| Methylmercury | 22967-92-6 |
| Molybdenum | 7439-98-7 |
| Norflurazon | 27314-13-2 |
| Oxyfluorfen | 42874-03-3 |
| Per- and polyfluoroalkyl substances (PFAS) | Multiple |
| Permethrin | 52645-53-1 |
| Phorate | 298-02-2 |
| Phosmet | 732-11-6 |
| Phostebupirim | 96182-53-5 |
| Profenofos | 41198-08-7 |
| Propachlor | 1918-16-7 |
| Propanil | 709-98-8 |
| Propargite | 2312-35-8 |
| Propazine | 139-40-2 |
| Propoxur | 114-26-1 |
| Quinoline | 91-22-5 |
| Tebuconazole | 107534-96-3 |
| Terbufos | 13071-79-9 |
| Thiamethoxam | 153719-23-4 |
| Tri-allate | 2303-17-5 |
| Tribufos | 78-48-8 |
| Tributyl phosphate | 126-73-8 |
| Trimethylbenzene (1,2,4-) | 95-63-6 |
| Tris(2-chloroethyl) phosphate (TCEP) | 115-96-8 |
| Tungsten | 7440-33-7 |
| Vanadium | 7440-62-2 |
Source: Environmental Protection Agency
In addition to the aforementioned chemicals, 12 microbes and three chemical groups (i.e., cyanotoxins, disinfection byproducts, and per- and polyfluoroalkyl substances) are included on the Draft CCL 5. Subsequent regulation under the Safe Drinking Water Act (SDWA) may be required for substances on the list.
A complete list of all substances on the CCL, both the current version and previous ones, may be found on the EPA website.
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