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Priority List of Hazardous Substances

The Priority List of Hazardous Substances
That Will Be the Subject of Toxicological Profiles


What is the Substance Priority List (SPL)?


The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) section 104 (i), as amended by the Superfund Amendments and Reauthorization Act (SARA), requires ATSDR and the EPA to prepare a list, in order of priority, of substances that are most commonly found at facilities on the National Priorities List (NPL) and which are determined to pose the most significant potential threat to human health due to their known or suspected toxicity and potential for human exposure at these NPL sites. CERCLA also requires this list to be revised periodically to reflect additional information on hazardous substances.

This substance priority list is revised and published on a 2-year basis, with a yearly informal review and revision. (No list was published in 2009 while ATSDR transitioned to a new agency science database.) Each substance on the list is a candidate to become the subject of a toxicological profile prepared by ATSDR. The listing algorithm prioritizes substances based on frequency of occurrence at NPL sites, toxicity, and potential for human exposure to the substances found at NPL sites.

It should be noted that this priority list is not a list of "most toxic" substances, but rather a prioritization of substances based on a combination of their frequency, toxicity, and potential for human exposure at NPL sites.

Thus, it is possible for substances with low toxicity but high NPL frequency of occurrence and exposure to be on this priority list. The objective of this priority list is to rank substances across all NPL hazardous waste sites to provide guidance in selecting which substances will be the subject of toxicological profiles prepared by ATSDR.

Where can I find more information on the Substance Priority List?


There is a Support Document to the Priority List of Hazardous Substances that describes in detail how the list is developed. There is also a Detailed Data Table showing the breakdown of the total scores for each substance on the priority list. These documents and other supporting information are available on the Substance Priority List Resource Page.

The ATSDR 2011 Substance Priority List

2011
RANK
SUBSTANCE NAME TOTAL
POINTS
2007
RANK
CAS RN
1 ARSENIC 1665.5 1 007440-38-2
2 LEAD 1529.1 2 007439-92-1
3 MERCURY 1460.9 3 007439-97-6
4 VINYL CHLORIDE 1361.1 4 000075-01-4
5 POLYCHLORINATED BIPHENYLS 1344.1 5 001336-36-3
6 BENZENE 1332.0 6 000071-43-2
7 CADMIUM 1318.7 7 007440-43-9
8 BENZO(A)PYRENE 1305.7 9 000050-32-8
9 POLYCYCLIC AROMATIC HYDROCARBONS 1282.3 8 130498-29-2
10 BENZO(B)FLUORANTHENE 1252.4 10 000205-99-2
11 CHLOROFORM 1207.5 11 000067-66-3
12 AROCLOR 1260 1190.0 14 011096-82-5
13 DDT, P,P'- 1183.0 12 000050-29-3
14 AROCLOR 1254 1171.7 13 011097-69-1
15 DIBENZO(A,H)ANTHRACENE 1155.2 15 000053-70-3
16 TRICHLOROETHYLENE 1151.1 16 000079-01-6
17 CHROMIUM, HEXAVALENT 1146.6 18 018540-29-9
18 DIELDRIN 1143.1 17 000060-57-1
19 PHOSPHORUS, WHITE 1141.9 19 007723-14-0
20 HEXACHLOROBUTADIENE 1128.5 22 000087-68-3
21 DDE, P,P'- 1127.2 21 000072-55-9
22 CHLORDANE 1126.4 20 000057-74-9
23 COAL TAR CREOSOTE 1124.8 23 008001-58-9
24 AROCLOR 1242 1123.8 29 053469-21-9
25 ALDRIN 1115.8 24 000309-00-2
26 DDD, P,P'- 1114.2 25 000072-54-8
27 AROCLOR 1248 1103.9 27 012672-29-6
28 HEPTACHLOR 1101.1 34 000076-44-8
29 AROCLOR 1099.4 30 012767-79-2
30 BENZIDINE 1090.6 26 000092-87-5
31 ACROLEIN 1088.5 37 000107-02-8
32 TOXAPHENE 1087.7 31 008001-35-2
33 TETRACHLOROETHYLENE 1077.4 33 000127-18-4
34 HEXACHLOROCYCLOHEXANE, GAMMA- 1074.7 32 000058-89-9
35 CYANIDE 1071.9 28 000057-12-5
36 HEXACHLOROCYCLOHEXANE, BETA- 1053.5 36 000319-85-7
37 BENZO(A)ANTHRACENE 1047.6 39 000056-55-3
38 DISULFOTON 1047.2 38 000298-04-4
39 1,2-DIBROMOETHANE 1041.9 35 000106-93-4
40 ENDRIN 1038.3 41 000072-20-8
41 DIAZINON 1036.7 56 000333-41-5
42 HEXACHLOROCYCLOHEXANE, DELTA- 1034.8 43 000319-86-8
43 BERYLLIUM 1032.7 42 007440-41-7
44 ENDOSULFAN 1028.0 54 000115-29-7
45 AROCLOR 1221 1027.1 48 011104-28-2
46 1,2-DIBROMO-3-CHLOROPROPANE 1025.8 44 000096-12-8
47 HEPTACHLOR EPOXIDE 1021.4 46 001024-57-3
48 ENDOSULFAN, ALPHA 1018.4 57 000959-98-8
49 CIS-CHLORDANE 1016.1 59 005103-71-9
50 CARBON TETRACHLORIDE 1015.5 47 000056-23-5
51 AROCLOR 1016 1011.9 51 012674-11-2
52 COBALT 1010.9 49 007440-48-4
53 PENTACHLOROPHENOL 1009.0 45 000087-86-5
54 DDT, O,P'- 1007.9 50 000789-02-6
55 METHOXYCHLOR 1006.3 61 000072-43-5
56 ENDOSULFAN SULFATE 1003.9 55 001031-07-8
57 NICKEL 998.7 53 007440-02-0
58 DI-N-BUTYL PHTHALATE 997.3 52 000084-74-2
59 ENDRIN KETONE 992.0 63 053494-70-5
60 DIBROMOCHLOROPROPANE 983.0 60 067708-83-2
61 BENZO(K)FLUORANTHENE 972.2 62 000207-08-9
62 XYLENES, TOTAL 969.2 58 001330-20-7
63 TRANS-CHLORDANE 968.3 64 005103-74-2
64 ENDOSULFAN, BETA 967.6 67 033213-65-9
65 CHLORPYRIFOS 963.9 127 002921-88-2
66 CHROMIUM(VI) TRIOXIDE 960.0 65 001333-82-0
67 AROCLOR 1232 958.2 68 011141-16-5
68 ENDRIN ALDEHYDE 957.7 69 007421-93-4
69 METHANE 953.4 66 000074-82-8
70 2-HEXANONE 941.4 72 000591-78-6
71 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN 940.9 73 001746-01-6
72 3,3'-DICHLOROBENZIDINE 940.6 40 000091-94-1
73 BENZOFLUORANTHENE 935.7 70 056832-73-6
74 TOLUENE 924.1 71 000108-88-3
75 ZINC 919.1 74 007440-66-6
76 DI(2-ETHYLHEXYL)PHTHALATE 908.0 76 000117-81-7
77 PENTACHLOROBENZENE 906.8 155 000608-93-5
78 CHROMIUM 897.5 77 007440-47-3
79 AROCLOR 1240 888.3 81 071328-89-7
80 NAPHTHALENE 881.4 78 000091-20-3
81 1,1-DICHLOROETHENE 879.5 79 000075-35-4
82 2,4,6-TRINITROTOLUENE 877.5 82 000118-96-7
83 2,4,6-TRICHLOROPHENOL 866.4 86 000088-06-2
84 BIS(2-CHLOROETHYL) ETHER 866.3 88 000111-44-4
85 BROMODICHLOROETHANE 866.2 83 000683-53-4
86 METHYLENE CHLORIDE 865.6 80 000075-09-2
87 DDD, O,P'- 865.6 151 000053-19-0
88 HYDRAZINE 860.8 84 000302-01-2
89 2,4-DINITROPHENOL 858.4 87 000051-28-5
90 4,4'-METHYLENEBIS(2-CHLOROANILINE) 857.2 152 000101-14-4
91 1,2-DICHLOROETHANE 853.6 85 000107-06-2
92 THIOCYANATE 845.8 89 000302-04-5
93 HEXACHLOROBENZENE 844.3 93 000118-74-1
94 ASBESTOS 841.4 90 001332-21-4
95 RADIUM-226 833.3 95 013982-63-3
96 RDX (CYCLOTRIMETHYLENETRINITRAMINE) 831.8 92 000121-82-4
97 URANIUM 831.8 98 007440-61-1
98 2,4-DINITROTOLUENE 831.2 94 000121-14-2
99 ETHION 829.9 96 000563-12-2
100 RADIUM 827.7 100 007440-14-4
101 4,6-DINITRO-O-CRESOL 827.3 102 000534-52-1
102 THORIUM 823.4 101 007440-29-1
103 DIMETHYLARSINIC ACID 821.2 75 000075-60-5
104 CHLORINE 820.6 91 007782-50-5
105 RADON 818.6 105 010043-92-2
106 1,3,5-TRINITROBENZENE 818.6 103 000099-35-4
107 HEXACHLOROCYCLOHEXANE, ALPHA- 817.3 115 000319-84-6
108 RADIUM-228 815.3 106 015262-20-1
109 THORIUM-230 813.7 107 014269-63-7
110 1,1,1-TRICHLOROETHANE 812.4 97 000071-55-6
111 URANIUM-235 812.1 107 015117-96-1
112 URANIUM-234 809.6 111 013966-29-5
113 THORIUM-228 809.5 113 014274-82-9
114 RADON-222 809.3 114 014859-67-7
115 COAL TARS 808.2 118 008007-45-2
116 ETHYLBENZENE 807.7 99 000100-41-4
117 CHLOROBENZENE 807.0 104 000108-90-7
118 N-NITROSODI-N-PROPYLAMINE 806.9 112 000621-64-7
119 CHRYSOTILE ASBESTOS 806.2 119 012001-29-5
120 METHYLMERCURY 806.0 123 022967-92-6
120 PLUTONIUM-239 806.0 121 015117-48-3
122 POLONIUM-210 805.6 122 013981-52-7
123 PLUTONIUM-238 805.2 124 013981-16-3
124 LEAD-210 805.1 125 014255-04-0
125 COPPER 804.7 128 007440-50-8
126 BARIUM 804.7 109 007440-39-3
127 AMOSITE ASBESTOS 804.3 131 012172-73-5
127 PLUTONIUM 804.3 126 007440-07-5
127 STRONTIUM-90 804.3 119 010098-97-2
130 RADON-220 804.2 130 022481-48-7
131 AMERICIUM-241 803.8 129 086954-36-1
132 TRIBUTYLTIN 802.9 134 000688-73-3
133 FLUORANTHENE 802.6 110 000206-44-0
134 AZINPHOS-METHYL 802.6 135 000086-50-0
135 CHLORDECONE 802.1 138 000143-50-0
136 NEPTUNIUM-237 801.9 136 013994-20-2
137 HYDROGEN CYANIDE 801.5 133 000074-90-8
138 PLUTONIUM-240 801.4 138 014119-33-6
139 1,2,3-TRICHLOROBENZENE 800.3 116 000087-61-6
140 MANGANESE 799.4 117 007439-96-5
141 S,S,S-TRIBUTYL PHOSPHOROTRITHIOATE 797.6 141 000078-48-8
142 CHRYSENE 793.4 137 000218-01-9
143 2,4,5-TRICHLOROPHENOL 790.4 222 000095-95-4
144 POLYBROMINATED BIPHENYLS 784.3 143 067774-32-7
145 DICOFOL 783.8 144 000115-32-2
146 SELENIUM 778.3 147 007782-49-2
147 1,1,2,2-TETRACHLOROETHANE 777.5 146 000079-34-5
148 HEPTACHLORODIBENZO-P-DIOXIN 773.8 154 037871-00-4
149 PARATHION 773.5 145 000056-38-2
150 HEXACHLOROCYCLOHEXANE, TECHNICAL GRADE 773.2 148 000608-73-1
151 TRICHLOROFLUOROETHANE 772.4 149 027154-33-2
152 BROMINE 770.1 142 007726-95-6
153 HEPTACHLORODIBENZOFURAN 755.5 166 038998-75-3
154 TRIFLURALIN 754.3 150 001582-09-8
155 1,3-BUTADIENE 750.4 156 000106-99-0
156 1,2,3,4,6,7,8,9-OCTACHLORODIBENZOFURAN 742.9 162 039001-02-0
157 AMMONIA 741.8 157 007664-41-7
158 2-METHYLNAPHTHALENE 728.9 158 000091-57-6
159 1,4-DICHLOROBENZENE 725.5 159 000106-46-7
160 1,1-DICHLOROETHANE 725.0 160 000075-34-3
161 2,3,4,7,8-PENTACHLORODIBENZOFURAN 723.6 168 057117-31-4
162 NALED 720.6 235 000300-76-5
163 HEXACHLOROCYCLOPENTADIENE 718.1 165 000077-47-4
164 1,2-DIPHENYLHYDRAZINE 717.9 167 000122-66-7
165 1,1,2-TRICHLOROETHANE 717.0 163 000079-00-5
166 PHORATE 715.2 225 000298-02-2
167 TRICHLOROETHANE 713.8 164 025323-89-1
168 ACENAPHTHENE 711.8 161 000083-32-9
169 TETRACHLOROBIPHENYL 709.2 169 026914-33-0
170 OXYCHLORDANE 705.5 171 027304-13-8
171 PALLADIUM 705.4 180 007440-05-3
172 CRESOL, PARA- 704.8 170 000106-44-5
173 INDENO(1,2,3-CD)PYRENE 702.6 174 000193-39-5
174 GAMMA-CHLORDENE 701.9 175 056641-38-4
175 1,2-DICHLOROBENZENE 698.0 172 000095-50-1
176 TETRACHLOROPHENOL 697.0 177 025167-83-3
177 1,2-DICHLOROETHENE, TRANS- 695.5 173 000156-60-5
178 CHLOROETHANE 688.9 183 000075-00-3
179 PHENOL 688.4 182 000108-95-2
180 P-XYLENE 686.6 185 000106-42-3
181 ALUMINUM 684.7 187 007429-90-5
182 CARBON DISULFIDE 683.0 176 000075-15-0
183 CARBON MONOXIDE 682.2 189 000630-08-0
184 2,4-DIMETHYLPHENOL 680.5 188 000105-67-9
185 DIBENZOFURAN 677.3 186 000132-64-9
186 ACETONE 676.5 184 000067-64-1
187 HEXACHLOROETHANE 669.4 197 000067-72-1
188 BUTYL METHYL PHTHALATE 667.4 194 034006-76-3
189 CHLOROMETHANE 666.3 193 000074-87-3
190 HEXACHLORODIBENZOFURAN 660.1 181 055684-94-1
191 BUTYL BENZYL PHTHALATE 659.1 195 000085-68-7
192 HYDROGEN SULFIDE 656.3 191 007783-06-4
193 DICHLORVOS 655.5 240 000062-73-7
194 CRESOL, ORTHO- 653.4 196 000095-48-7
195 DIBENZOFURANS, CHLORINATED 653.0 236 042934-53-2
196 HEXACHLORODIBENZO-P-DIOXIN 651.7 153 034465-46-8
197 VANADIUM 649.9 198 007440-62-2
198 N-NITROSODIMETHYLAMINE 648.3 199 000062-75-9
199 1,2,4-TRICHLOROBENZENE 647.4 200 000120-82-1
200 ETHOPROP 643.7 236 013194-48-4
201 TETRACHLORODIBENZO-P-DIOXIN 641.5 202 041903-57-5
202 BROMOFORM 635.1 201 000075-25-2
203 PENTACHLORODIBENZOFURAN 631.7 192 030402-15-4
204 1,3-DICHLOROBENZENE 628.6 203 000541-73-1
205 PENTACHLORODIBENZO-P-DIOXIN 625.9 204 036088-22-9
206 N-NITROSODIPHENYLAMINE 625.8 205 000086-30-6
207 2,3,7,8-TETRACHLORODIBENZOFURAN 618.9 207 051207-31-9
208 2,4-DICHLOROPHENOL 618.5 209 000120-83-2
209 2,3-DIMETHYLNAPHTHALENE 617.5 New 000581-40-8
210 1,4-DIOXANE 613.5 210 000123-91-1
211 FLUORINE 613.3 211 007782-41-4
212 2-BUTANONE 611.1 208 000078-93-3
213 1,2-DICHLOROETHYLENE 610.4 206 000540-59-0
214 CESIUM-137 610.0 213 010045-97-3
214 CHROMIC ACID 610.0 215 007738-94-5
216 NITRITE 609.0 212 014797-65-0
217 SILVER 608.1 214 007440-22-4
218 POTASSIUM-40 607.6 217 013966-00-2
219 DINITROTOLUENE 607.3 218 025321-14-6
220 NITRATE 606.0 216 014797-55-8
221 COAL TAR PITCH 605.2 220 065996-93-2
222 THORIUM-227 605.0 221 015623-47-9
223 ARSENIC ACID 604.3 223 007778-39-4
224 ARSENIC TRIOXIDE 603.8 224 001327-53-3
225 BENZOPYRENE 602.9 226 073467-76-2
226 CHLORDANE, TECHNICAL 602.5 228 012789-03-6
227 STROBANE 602.5 230 008001-50-1
228 4-AMINOBIPHENYL 602.4 232 000092-67-1
228 PYRETHRUM 602.4 232 008003-34-7
230 ARSINE 602.4 234 007784-42-1
230 DIMETHOATE 602.4 229 000060-51-5
232 ANTIMONY 602.2 219 007440-36-0
233 CARBOPHENOTHION 601.9 238 000786-19-6
234 ALPHA-CHLORDENE 601.4 238 056534-02-2
234 IODINE-131 601.4 132 010043-66-0
234 MERCURIC CHLORIDE 601.4 241 007487-94-7
234 SODIUM ARSENITE 601.4 241 007784-46-5
234 URANIUM-233 601.4 178 013968-55-3
239 DIBROMOCHLOROMETHANE 600.5 249 000124-48-1
240 CRESOLS 597.1 227 001319-77-3
241 FORMALDEHYDE 596.0 244 000050-00-0
242 DICHLOROBENZENE 595.4 254 025321-22-6
243 2,4-D ACID 594.5 248 000094-75-7
244 2-CHLOROPHENOL 591.1 245 000095-57-8
245 BUTYLATE 589.9 251 002008-41-5
246 PHENANTHRENE 588.3 246 000085-01-8
247 DIMETHYL FORMAMIDE 585.3 252 000068-12-2
248 4-NITROPHENOL 580.0 257 000100-02-7
249 DIURON 578.7 250 000330-54-1
250 TETRACHLOROETHANE 576.7 190 025322-20-7
251 DICHLOROETHANE 567.8 256 001300-21-6
252 ETHYL ETHER 565.2 255 000060-29-7
253 PYRENE 564.1 253 000129-00-0
254 DIMETHYLANILINE 561.8 New 000121-69-7
255 1,3-DICHLOROPROPENE, CIS- 561.0 258 010061-01-5
256 1,2,3,4,6,7,8-HEPTACHLORODIBENZO-P-DIOXIN 558.9 263 035822-46-9
257 PHOSPHINE 555.2 259 007803-51-2
258 TRICHLOROBENZENE 555.1 260 012002-48-1
259 2,6-DINITROTOLUENE 554.4 261 000606-20-2
260 FLUORIDE ION 549.9 262 016984-48-8
261 1,2,3,4,6,7,8-HEPTACHLORODIBENZOFURAN 548.8 273 067562-39-4
262 PENTAERYTHRITOL TETRANITRATE 548.2 265 000078-11-5
263 1,3-DICHLOROPROPENE, TRANS- 548.0 266 010061-02-6
264 ACRYLONITRILE 543.2 274 000107-13-1
265 BIS(2-ETHYLHEXYL)ADIPATE 542.4 267 000103-23-1
266 CARBAZOLE 538.6 268 000086-74-8
267 METOLACHLOR 538.2 New 051218-45-2
268 2-CHLOROANILINE 537.9 New 000095-51-2
269 1,2,3-TRICHLOROPROPANE 536.1 New 000096-18-4
270 CARBARYL 535.5 272 000063-25-2
271 1,2-DICHLOROETHENE, CIS- 533.8 270 000156-59-2
272 METHYL ISOBUTYL KETONE 529.6 269 000108-10-1
273 STYRENE 529.4 271 000100-42-5
274 THALLIUM 525.3 New 007440-28-0
275 1,2,3,7,8,9-HEXACHLORODIBENZOFURAN 524.3 New 072918-21-9

Substances were assigned the same rank when two (or more) substances received equivalent total point scores.

CAS RN = Chemical Abstracts Service Registry Number

 

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