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The Priority List of Hazardous Substances That Will Be the Candidates for 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 2015 Substance Priority List

2015
RANK		 SUBSTANCE NAME TOTAL
POINTS		 2013
RANK		 CAS RN
1 ARSENIC 1671.6 1 007440-38-2
2 LEAD 1529.4 2 007439-92-1
3 MERCURY 1458.6 3 007439-97-6
4 VINYL CHLORIDE 1358.9 4 000075-01-4
5 POLYCHLORINATED BIPHENYLS 1345.1 5 001336-36-3
6 BENZENE 1327.6 6 000071-43-2
7 CADMIUM 1318.8 7 007440-43-9
8 BENZO(A)PYRENE 1304.4 8 000050-32-8
9 POLYCYCLIC AROMATIC HYDROCARBONS 1279.1 9 130498-29-2
10 BENZO(B)FLUORANTHENE 1249.7 10 000205-99-2
11 CHLOROFORM 1202.4 11 000067-66-3
12 AROCLOR 1260 1190.0 12 011096-82-5
13 DDT, P,P'- 1182.0 13 000050-29-3
14 AROCLOR 1254 1171.3 14 011097-69-1
15 DIBENZO(A,H)ANTHRACENE 1155.6 15 000053-70-3
16 TRICHLOROETHYLENE 1153.4 16 000079-01-6
17 CHROMIUM, HEXAVALENT 1146.8 17 018540-29-9
18 DIELDRIN 1142.9 18 000060-57-1
19 PHOSPHORUS, WHITE 1141.3 19 007723-14-0
20 HEXACHLOROBUTADIENE 1128.2 20 000087-68-3
21 DDE, P,P'- 1125.9 21 000072-55-9
22 CHLORDANE 1125.6 22 000057-74-9
23 AROCLOR 1242 1124.7 24 053469-21-9
24 COAL TAR CREOSOTE 1124.4 23 008001-58-9
25 ALDRIN 1114.6 25 000309-00-2
26 DDD, P,P'- 1113.1 26 000072-54-8
27 AROCLOR 1248 1104.5 27 012672-29-6
28 HEPTACHLOR 1100.6 28 000076-44-8
29 AROCLOR 1099.5 29 012767-79-2
30 BENZIDINE 1091.2 30 000092-87-5
31 ACROLEIN 1088.5 31 000107-02-8
32 TOXAPHENE 1087.8 32 008001-35-2
33 TETRACHLOROETHYLENE 1076.7 33 000127-18-4
34 HEXACHLOROCYCLOHEXANE, GAMMA- 1075.1 34 000058-89-9
35 CYANIDE 1069.8 35 000057-12-5
36 HEXACHLOROCYCLOHEXANE, BETA- 1053.4 36 000319-85-7
37 DISULFOTON 1047.2 38 000298-04-4
38 BENZO(A)ANTHRACENE 1046.0 38 000056-55-3
39 1,2-DIBROMOETHANE 1041.7 39 000106-93-4
40 ENDRIN 1037.6 40 000072-20-8
41 DIAZINON 1036.6 41 000333-41-5
42 HEXACHLOROCYCLOHEXANE, DELTA- 1034.8 42 000319-86-8
43 BERYLLIUM 1031.0 43 007440-41-7
44 ENDOSULFAN 1027.7 44 000115-29-7
45 AROCLOR 1221 1027.0 45 011104-28-2
46 1,2-DIBROMO-3-CHLOROPROPANE 1025.7 46 000096-12-8
47 HEPTACHLOR EPOXIDE 1020.7 47 001024-57-3
48 ENDOSULFAN, ALPHA 1018.0 48 000959-98-8
49 CIS-CHLORDANE 1015.6 49 005103-71-9
50 CARBON TETRACHLORIDE 1012.1 50 000056-23-5
51 COBALT 1012.0 51 007440-48-4
52 AROCLOR 1016 1011.5 52 012674-11-2
53 DDT, O,P'- 1007.8 53 000789-02-6
54 PENTACHLOROPHENOL 1007.2 54 000087-86-5
55 METHOXYCHLOR 1005.9 55 000072-43-5
56 ENDOSULFAN SULFATE 1003.3 56 001031-07-8
57 NICKEL 995.7 57 007440-02-0
58 DI-N-BUTYL PHTHALATE 994.6 58 000084-74-2
59 ENDRIN KETONE 991.6 59 053494-70-5
60 DIBROMOCHLOROPROPANE 982.9 60 067708-83-2
61 BENZO(K)FLUORANTHENE 969.8 61 000207-08-9
62 TRANS-CHLORDANE 967.7 62 005103-74-2
63 ENDOSULFAN, BETA 967.1 63 033213-65-9
64 XYLENES, TOTAL 964.6 64 001330-20-7
65 CHLORPYRIFOS 963.8 65 002921-88-2
66 CHROMIUM(VI) TRIOXIDE 960.0 66 001333-82-0
67 AROCLOR 1232 957.9 67 011141-16-5
68 ENDRIN ALDEHYDE 957.4 68 007421-93-4
69 METHANE 952.7 69 000074-82-8
70 3,3'-DICHLOROBENZIDINE 940.4 70 000091-94-1
71 2-HEXANONE 940.2 71 000591-78-6
72 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN 939.8 72 001746-01-6
73 BENZOFLUORANTHENE 935.6 73 056832-73-6
74 TOLUENE 917.9 74 000108-88-3
75 ZINC 915.5 75 007440-66-6
76 PENTACHLOROBENZENE 906.8 76 000608-93-5
77 DI(2-ETHYLHEXYL)PHTHALATE 905.0 77 000117-81-7
78 CHROMIUM 895.6 78 007440-47-3
79 AROCLOR 1240 888.3 79 071328-89-7
80 NAPHTHALENE 877.4 80 000091-20-3
81 2,4,6-TRINITROTOLUENE 877.4 81 000118-96-7
82 1,1-DICHLOROETHENE 875.8 82 000075-35-4
83 BROMODICHLOROETHANE 866.3 83 000683-53-4
84 2,4,6-TRICHLOROPHENOL 866.0 84 000088-06-2
85 BIS(2-CHLOROETHYL) ETHER 865.9 85 000111-44-4
86 DDD, O,P'- 865.7 86 000053-19-0
87 HYDRAZINE 860.9 87 000302-01-2
88 METHYLENE CHLORIDE 860.0 88 000075-09-2
89 2,4-DINITROPHENOL 858.1 89 000051-28-5
90 4,4'-METHYLENEBIS(2-CHLOROANILINE) 857.3 90 000101-14-4
91 1,2-DICHLOROETHANE 852.7 91 000107-06-2
92 THIOCYANATE 845.9 92 000302-04-5
93 HEXACHLOROBENZENE 843.5 93 000118-74-1
94 ASBESTOS 840.8 94 001332-21-4
95 RADIUM-226 832.8 95 013982-63-3
96 RDX (Cyclonite) 831.9 96 000121-82-4
97 URANIUM 831.3 97 007440-61-1
98 2,4-DINITROTOLUENE 830.7 98 000121-14-2
99 ETHION 829.9 99 000563-12-2
100 RADIUM 827.2 100 007440-14-4
101 4,6-DINITRO-O-CRESOL 827.0 101 000534-52-1
102 THORIUM 823.9 102 007440-29-1
103 DIMETHYLARSINIC ACID 821.2 103 000075-60-5
104 CHLORINE 820.3 104 007782-50-5
105 1,3,5-TRINITROBENZENE 818.5 105 000099-35-4
106 RADON 818.3 106 010043-92-2
107 HEXACHLOROCYCLOHEXANE, ALPHA- 815.5 107 000319-84-6
108 RADIUM-228 815.1 108 015262-20-1
109 THORIUM-230 813.6 109 014269-63-7
110 URANIUM-235 812.0 110 015117-96-1
111 THORIUM-228 810.1 111 014274-82-9
112 URANIUM-234 809.5 112 013966-29-5
113 RADON-222 809.2 113 014859-67-7
114 COAL TARS 808.0 115 008007-45-2
115 METHYLMERCURY 807.8 116 022967-92-6
116 1,1,1-TRICHLOROETHANE 807.6 114 000071-55-6
117 N-NITROSODI-N-PROPYLAMINE 807.1 117 000621-64-7
118 COPPER 806.5 118 007440-50-8
119 CHRYSOTILE ASBESTOS 806.1 119 012001-29-5
120 PLUTONIUM-239 805.9 120 015117-48-3
121 POLONIUM-210 805.5 121 013981-52-7
122 PLUTONIUM-238 805.2 122 013981-16-3
123 LEAD-210 805.0 123 014255-04-0
124 AMOSITE ASBESTOS 804.2 125 012172-73-5
124 PLUTONIUM 804.2 125 007440-07-5
124 STRONTIUM-90 804.2 125 010098-97-2
127 RADON-220 804.1 128 022481-48-7
128 CHLOROBENZENE 803.9 124 000108-90-7
129 AMERICIUM-241 803.8 129 086954-36-1
130 ETHYLBENZENE 802.8 130 000100-41-4
131 AZINPHOS-METHYL 802.5 132 000086-50-0
132 BARIUM 802.1 131 007440-39-3
133 CHLORDECONE 802.1 133 000143-50-0
134 NEPTUNIUM-237 801.9 134 013994-20-2
135 HYDROGEN CYANIDE 801.7 135 000074-90-8
136 PLUTONIUM-240 801.4 136 014119-33-6
137 1,2,3-TRICHLOROBENZENE 800.1 137 000087-61-6
138 FLUORANTHENE 799.6 138 000206-44-0
139 MANGANESE 798.3 139 007439-96-5
140 S,S,S-TRIBUTYL PHOSPHOROTRITHIOATE 797.6 140 000078-48-8
141 CHRYSENE 791.3 141 000218-01-9
142 2,4,5-TRICHLOROPHENOL 790.3 142 000095-95-4
143 POLYBROMINATED BIPHENYLS 784.2 143 067774-32-7
144 DICOFOL 783.8 144 000115-32-2
145 SELENIUM 775.9 145 007782-49-2
146 1,1,2,2-TETRACHLOROETHANE 775.6 146 000079-34-5
147 HEPTACHLORODIBENZO-P-DIOXIN 773.4 147 037871-00-4
148 PARATHION 773.3 148 000056-38-2
149 HEXACHLOROCYCLOHEXANE, TECHNICAL GRADE 772.9 149 000608-73-1
150 TRICHLOROFLUOROETHANE 772.3 150 027154-33-2
151 BROMINE 770.0 151 007726-95-6
152 AROCLOR 1268 764.4 152 011100-14-4
153 1,3-BUTADIENE 760.9 153 000106-99-0
154 HEPTACHLORODIBENZOFURAN 755.2 154 038998-75-3
155 TRIFLURALIN 754.2 155 001582-09-8
156 1,2,3,4,6,7,8,9-OCTACHLORODIBENZOFURAN 742.6 156 039001-02-0
157 AMMONIA 741.1 157 007664-41-7
158 2-METHYLNAPHTHALENE 726.5 158 000091-57-6
159 2,3,4,7,8-PENTACHLORODIBENZOFURAN 723.3 160 057117-31-4
160 1,4-DICHLOROBENZENE 723.2 159 000106-46-7
161 1,1-DICHLOROETHANE 721.8 161 000075-34-3
162 NALED 720.4 162 000300-76-5
163 1,1,2-TRICHLOROETHANE 719.3 163 000079-00-5
164 HEXACHLOROCYCLOPENTADIENE 717.9 164 000077-47-4
165 1,2-DIPHENYLHYDRAZINE 717.6 165 000122-66-7
166 PHORATE 715.0 166 000298-02-2
167 TRICHLOROETHANE 712.1 167 025323-89-1
168 ACENAPHTHENE 710.0 168 000083-32-9
169 TETRACHLOROBIPHENYL 709.1 169 026914-33-0
170 OXYCHLORDANE 705.4 170 027304-13-8
171 PALLADIUM 705.3 171 007440-05-3
172 CRESOL, PARA- 703.0 172 000106-44-5
173 GAMMA-CHLORDENE 701.9 173 056641-38-4
174 INDENO(1,2,3-CD)PYRENE 701.9 174 000193-39-5
175 TETRACHLOROPHENOL 696.9 175 025167-83-3
176 1,2-DICHLOROBENZENE 696.4 176 000095-50-1
177 1,2-DICHLOROETHENE, TRANS- 691.7 177 000156-60-5
178 CHLOROETHANE 687.0 178 000075-00-3
179 ALUMINUM 686.0 179 007429-90-5
180 P-XYLENE 685.9 181 000106-42-3
181 PHENOL 685.7 180 000108-95-2
182 CARBON MONOXIDE 682.3 182 000630-08-0
183 CARBON DISULFIDE 681.6 183 000075-15-0
184 2,4-DIMETHYLPHENOL 679.0 184 000105-67-9
185 DIBENZOFURAN 675.5 185 000132-64-9
186 ACETONE 672.6 186 000067-64-1
187 HEXACHLOROETHANE 669.2 187 000067-72-1
188 BUTYL METHYL PHTHALATE 667.4 188 034006-76-3
189 CHLOROMETHANE 664.8 189 000074-87-3
190 HEXACHLORODIBENZOFURAN 659.7 190 055684-94-1
191 BUTYL BENZYL PHTHALATE 657.3 191 000085-68-7
192 HYDROGEN SULFIDE 656.2 192 007783-06-4
193 DICHLORVOS 655.3 193 000062-73-7
194 DIBENZOFURANS, CHLORINATED 652.8 194 042934-53-2
195 CRESOL, ORTHO- 652.2 195 000095-48-7
196 HEXACHLORODIBENZO-P-DIOXIN 651.2 196 034465-46-8
197 VANADIUM 649.8 197 007440-62-2
198 N-NITROSODIMETHYLAMINE 648.2 198 000062-75-9
199 1,2,4-TRICHLOROBENZENE 646.3 199 000120-82-1
200 ETHOPROP 643.4 200 013194-48-4
201 TETRACHLORODIBENZO-P-DIOXIN 641.0 201 041903-57-5
202 BROMOFORM 634.2 202 000075-25-2
203 PENTACHLORODIBENZOFURAN 631.2 203 030402-15-4
204 1,3-DICHLOROBENZENE 627.6 204 000541-73-1
205 PENTACHLORODIBENZO-P-DIOXIN 625.4 205 036088-22-9
206 N-NITROSODIPHENYLAMINE 624.6 206 000086-30-6
207 2,3,7,8-TETRACHLORODIBENZOFURAN 618.7 207 051207-31-9
208 2,4-DICHLOROPHENOL 618.0 208 000120-83-2
209 2,3-DIMETHYLNAPHTHALENE 617.6 209 000581-40-8
210 1,4-DIOXANE 614.8 210 000123-91-1
211 FLUORINE 613.2 211 007782-41-4
212 CESIUM-137 609.9 212 010045-97-3
212 CHROMIC ACID 609.9 212 007738-94-5
214 NITRITE 608.9 214 014797-65-0
215 2-BUTANONE 607.9 215 000078-93-3
216 1,2-DICHLOROETHYLENE 607.6 216 000540-59-0
217 POTASSIUM-40 607.5 217 013966-00-2
218 DINITROTOLUENE 607.2 218 025321-14-6
219 COAL TAR PITCH 605.2 220 065996-93-2
220 SILVER 604.9 219 007440-22-4
221 THORIUM-227 604.9 222 015623-47-9
222 NITRATE 604.9 221 014797-55-8
223 ARSENIC ACID 604.3 223 007778-39-4
224 FORMALDEHYDE 604.2 224 000050-00-0
225 ARSENIC TRIOXIDE 603.8 225 001327-53-3
226 BENZOPYRENE 603.4 226 073467-76-2
227 CHLORDANE, TECHNICAL 602.5 227 012789-03-6
228 STROBANE 602.5 228 008001-50-1
229 4-AMINOBIPHENYL 602.4 229 000092-67-1
229 PYRETHRUM 602.4 229 008003-34-7
231 ARSINE 602.4 231 007784-42-1
232 DIMETHOATE 602.4 231 000060-51-5
233 BIS(CHLOROMETHYL) ETHER 601.9 New 000542-88-1
233 CARBOPHENOTHION 601.9 233 000786-19-6
235 ALPHA-CHLORDENE 601.4 234 056534-02-2
235 IODINE-131 601.4 234 010043-66-0
235 MERCURIC CHLORIDE 601.4 234 007487-94-7
235 SODIUM ARSENITE 601.4 234 007784-46-5
235 URANIUM-233 601.4 234 013968-55-3
240 ANTIMONY 601.0 239 007440-36-0
241 DIBROMOCHLOROMETHANE 599.4 240 000124-48-1
242 CRESOLS 596.7 241 001319-77-3
243 DICHLOROBENZENE 594.8 242 025321-22-6
244 2,4-D ACID 594.3 243 000094-75-7
245 2-CHLOROPHENOL 590.5 244 000095-57-8
246 BUTYLATE 589.9 245 002008-41-5
247 DIMETHYL FORMAMIDE 585.2 247 000068-12-2
248 PHENANTHRENE 584.7 246 000085-01-8
249 4-NITROPHENOL 579.3 248 000100-02-7
250 DIURON 578.7 249 000330-54-1
251 TETRACHLOROETHANE 576.4 250 025322-20-7
252 DICHLOROETHANE 567.3 251 001300-21-6
253 ETHYL ETHER 564.9 252 000060-29-7
254 DIMETHYLANILINE 561.7 253 000121-69-7
255 PYRENE 560.9 254 000129-00-0
256 1,3-DICHLOROPROPENE, CIS- 560.5 255 010061-01-5
257 1,2,3,4,6,7,8-HEPTACHLORODIBENZO-P-DIOXIN 558.6 256 035822-46-9
258 PHOSPHINE 555.3 257 007803-51-2
259 TRICHLOROBENZENE 554.8 258 012002-48-1
260 2,6-DINITROTOLUENE 554.0 259 000606-20-2
261 FLUORIDE ION 548.9 260 016984-48-8
262 1,2,3,4,6,7,8-HEPTACHLORODIBENZOFURAN 548.5 261 067562-39-4
263 PENTAERYTHRITOL TETRANITRATE 548.1 262 000078-11-5
264 1,3-DICHLOROPROPENE, TRANS- 547.6 263 010061-02-6
265 ACRYLONITRILE 543.0 264 000107-13-1
266 BIS(2-ETHYLHEXYL)ADIPATE 542.3 265 000103-23-1
267 1,2-DICHLOROETHENE, CIS- 540.8 271 000156-59-2
268 CARBAZOLE 539.8 266 000086-74-8
269 METOLACHLOR 538.2 267 051218-45-2
270 2-CHLOROANILINE 538.0 268 000095-51-2
271 1,2,3-TRICHLOROPROPANE 535.9 269 000096-18-4
272 CARBARYL 535.4 270 000063-25-2
273 STYRENE 527.9 272 000100-42-5
274 METHYL ISOBUTYL KETONE 527.3 273 000108-10-1
275 THALLIUM 524.5 274 007440-28-0

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

CAS #= Chemical Abstracts Service Registry Number

 

Contact Information

Further information can be obtained by contacting the ATSDR Information Center at:

Agency for Toxic Substances and Disease Registry
Division of Toxicology and Human Health Sciences
1600 Clifton Road NE, Mailstop F-57
Atlanta, GA 30333
Phone: 1-800-CDC-INFO 888-232-6348 (TTY)
Email: Contact CDC-INFO

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