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Water: Contaminant Candidate List

CCL 2 List and Regulatory Determinations

On February 23, 2005, EPA announced the second Drinking Water Contaminant Candidate List (CCL) and our efforts to expand and strengthen the underlying CCL listing process to be used for future CCLs.

Microbial Contaminant Candidates

Microbial Contaminants
Aeromonas hydrophila
Cyanobacteria (blue-green algae), other freshwater algae, and their toxins
Helicobacter pylori
Microsporidia (Enterocytozoon & Septata)
Mycobacterium avium intracellulare (MAC)

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Chemical Contaminant Candidates

Chemical Contaminant Chemical Abstract Service Registration NumberCASRN1
1,1,2,2-tetrachloroethane 79-34-5
1,2,4-trimethylbenzene 95-63-6
1,1-dichloroethane 75-34-3
1,1-dichloropropene 563-58-6
1,2-diphenylhydrazine 122-66-7
1,3-dichloropropane 142-28-9
1,3-dichloropropene 542-75-6
2,4,6-trichlorophenol 88-06-2
2,2-dichloropropane 594-20-7
2,4-dichlorophenol 120-83-2
2,4-dinitrophenol 51-28-5
2,4-dinitrotoluene 121-14-2
2,6-dinitrotoluene 606-20-2
2-methyl-Phenol (o-cresol) 95-48-7
Acetochlor 34256-82-1
Alachlor ESA & other acetanilide pesticide degradation products N/A
Aluminum 7429-90-5
Boron 7440-42-8
Bromobenzene 108-86-1
DCPA mono-acid degradate 887-54-7
DCPA di-acid degradate 2136-79-0
DDE 72-55-9
Diazinon 333-41-5
Disulfoton 298-04-4
Diuron 330-54-1
EPTC (s-ethyl-dipropylthiocarbamate) 759-94-4
Fonofos 944-22-9
p-Isopropyltoluene (p-cymene) 99-87-6
Linuron 330-55-2
Methyl bromide 74-83-9
Methyl-t-butyl ether (MTBE) 1634-04-4
Metolachlor 51218-45-2
Molinate 2212-67-1
Nitrobenzene 98-95-3
Organotins N/A
Perchlorate 14797-73-0
Prometon 1610-18-0
RDX 121-82-4
Terbacil 5902-51-2
Terbufos 13071-79-9
Triazines & degradation products of triazines including, but not limited to Cyanazine 21725-46-2 and atrazine-desethyl 6190-65-4
Vanadium 7440-62-2


1Chemical Abstract Service Registration Number (CASRN#) - Chemical abstract service registry numbers are used in reference works, databases, and regulatory compliance documents by many organizations around the world to identify substances with a standardized name.

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