ATSDR – Priority List of Hazardous Substances

ATSDR – 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 2013 Substance Priority List

2013 RANK	SUBSTANCE NAME	TOTAL  POINTS	2011 RANK	CAS RN
1	ARSENIC	1670.4	1	007440-38-2
2	LEAD	1529.2	2	007439-92-1
3	MERCURY	1458.6	3	007439-97-6
4	VINYL CHLORIDE	1359.8	4	000075-01-4
5	POLYCHLORINATED BIPHENYLS	1343.5	5	001336-36-3
6	BENZENE	1328.5	6	000071-43-2
7	CADMIUM	1318.7	7	007440-43-9
8	BENZO(A)PYRENE	1304.7	8	000050-32-8
9	POLYCYCLIC AROMATIC HYDROCARBONS	1279.7	9	130498-29-2
10	BENZO(B)FLUORANTHENE	1251.2	10	000205-99-2
11	CHLOROFORM	1203.5	11	000067-66-3
12	AROCLOR 1260	1190.3	12	011096-82-5
13	DDT, P,P'-	1181.5	13	000050-29-3
14	AROCLOR 1254	1171.2	14	011097-69-1
15	DIBENZO(A,H)ANTHRACENE	1155.4	15	000053-70-3
16	TRICHLOROETHYLENE	1151.4	16	000079-01-6
17	CHROMIUM, HEXAVALENT	1146.9	17	018540-29-9
18	DIELDRIN	1142.5	18	000060-57-1
19	PHOSPHORUS, WHITE	1141.4	19	007723-14-0
20	HEXACHLOROBUTADIENE	1128.2	20	000087-68-3
21	DDE, P,P'-	1126.2	21	000072-55-9
22	CHLORDANE	1125.9	22	000057-74-9
23	COAL TAR CREOSOTE	1124.5	23	008001-58-9
24	AROCLOR 1242	1124.3	24	053469-21-9
25	ALDRIN	1114.6	25	000309-00-2
26	DDD, P,P'-	1113.3	26	000072-54-8
27	AROCLOR 1248	1103.8	27	012672-29-6
28	HEPTACHLOR	1100.7	28	000076-44-8
29	AROCLOR	1099.4	29	012767-79-2
30	BENZIDINE	1090.5	30	000092-87-5
31	ACROLEIN	1088.4	31	000107-02-8
32	TOXAPHENE	1087.4	32	008001-35-2
33	TETRACHLOROETHYLENE	1075.7	33	000127-18-4
34	YHEXACHLOROCYCLOHEXANE, GAMMA-	1074.9	34	000058-89-9
35	CYANIDE	1070.2	35	000057-12-5
36	HEXACHLOROCYCLOHEXANE, BETA-	1053.5	36	000319-85-7
37	DISULFOTON	1047.1	38	000298-04-4
38	BENZO(A)ANTHRACENE	1046.0	37	000056-55-3
39	1,2-DIBROMOETHANE	1041.7	39	000106-93-4
40	ENDRIN	1037.7	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	1020.9	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	1012.6	50	000056-23-5
51	COBALT	1011.7	52	007440-48-4
52	AROCLOR 1016	1011.5	51	012674-11-2
53	DDT, O,P'-	1007.8	54	000789-02-6
54	PENTACHLOROPHENOL	1007.6	53	000087-86-5
55	METHOXYCHLOR	1005.9	55	000072-43-5
56	ENDOSULFAN SULFATE	1003.4	56	001031-07-8
57	NICKEL	996.2	57	007440-02-0
58	DI-N-BUTYL PHTHALATE	994.9	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	971.3	61	000207-08-9
62	TRANS-CHLORDANE	967.8	63	005103-74-2
63	ENDOSULFAN, BETA	967.2	64	033213-65-9
64	XYLENES, TOTAL	965.3	62	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	952.8	69	000074-82-8
70	3,3'-DICHLOROBENZIDINE	940.4	72	000091-94-1
71	2-HEXANONE	940.3	70	000591-78-6
72	2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN	939.9	71	001746-01-6
73	BENZOFLUORANTHENE	935.6	73	056832-73-6
74	TOLUENE	918.8	74	000108-88-3
75	ZINC	915.5	75	007440-66-6
76	PENTACHLOROBENZENE	906.8	77	000608-93-5
77	DI(2-ETHYLHEXYL)PHTHALATE	905.2	76	000117-81-7
78	CHROMIUM	896.4	78	007440-47-3
79	AROCLOR 1240	888.3	79	071328-89-7
80	NAPHTHALENE	878.0	80	000091-20-3
81	2,4,6-TRINITROTOLUENE	877.3	82	000118-96-7
82	1,1-DICHLOROETHENE	876.6	81	000075-35-4
83	BROMODICHLOROETHANE	866.2	85	000683-53-4
84	2,4,6-TRICHLOROPHENOL	866.0	83	000088-06-2
85	BIS(2-CHLOROETHYL) ETHER	865.9	84	000111-44-4
86	DDD, O,P'-	865.6	87	000053-19-0
87	HYDRAZINE	860.8	88	000302-01-2
88	METHYLENE CHLORIDE	860.8	86	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	853.3	91	000107-06-2
92	THIOCYANATE	845.8	92	000302-04-5
93	HEXACHLOROBENZENE	843.6	93	000118-74-1
94	ASBESTOS	840.9	94	001332-21-4
95	RADIUM-226	832.9	95	013982-63-3
96	RDX (Cyclonite)	831.9	96	000121-82-4
97	URANIUM	831.4	97	007440-61-1
98	2,4-DINITROTOLUENE	830.8	98	000121-14-2
99	ETHION	829.9	99	000563-12-2
100	RADIUM	827.3	100	007440-14-4
101	4,6-DINITRO-O-CRESOL	827.0	101	000534-52-1
102	THORIUM	824.0	102	007440-29-1
103	DIMETHYLARSINIC ACID	821.1	103	000075-60-5
104	CHLORINE	820.3	104	007782-50-5
105	1,3,5-TRINITROBENZENE	818.5	106	000099-35-4
106	RADON	818.4	105	010043-92-2
107	HEXACHLOROCYCLOHEXANE, ALPHA-	816.7	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	111	015117-96-1
111	THORIUM-228	810.2	113	014274-82-9
112	URANIUM-234	809.5	112	013966-29-5
113	RADON-222	809.2	114	014859-67-7
114	1,1,1-TRICHLOROETHANE	808.4	110	000071-55-6
115	COAL TARS	808.1	115	008007-45-2
116	METHYLMERCURY	807.2	120	022967-92-6
117	N-NITROSODI-N-PROPYLAMINE	807.2	118	000621-64-7
118	COPPER	806.9	125	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	122	013981-52-7
122	PLUTONIUM-238	805.2	123	013981-16-3
123	LEAD-210	805.1	124	014255-04-0
124	CHLOROBENZENE	804.3	117	000108-90-7
125	AMOSITE ASBESTOS	804.2	127	012172-73-5
125	PLUTONIUM	804.2	127	007440-07-5
125	STRONTIUM-90	804.2	127	010098-97-2
128	RADON-220	804.2	130	022481-48-7
129	AMERICIUM-241	803.8	131	086954-36-1
130	ETHYLBENZENE	803.5	116	000100-41-4
131	BARIUM	802.8	126	007440-39-3
132	AZINPHOS-METHYL	802.5	134	000086-50-0
133	CHLORDECONE	802.1	135	000143-50-0
134	NEPTUNIUM-237	801.9	136	013994-20-2
135	HYDROGEN CYANIDE	801.6	137	000074-90-8
136	PLUTONIUM-240	801.4	138	014119-33-6
137	1,2,3-Trichlorobenzene	800.1	139	000087-61-6
138	FLUORANTHENE	800.0	133	000206-44-0
139	MANGANESE	798.8	140	007439-96-5
140	S,S,S-TRIBUTYL PHOSPHOROTRITHIOATE	797.5	141	000078-48-8
141	CHRYSENE	791.8	142	000218-01-9
142	2,4,5-TRICHLOROPHENOL	790.2	143	000095-95-4
143	POLYBROMINATED BIPHENYLS	784.2	144	067774-32-7
144	DICOFOL	783.7	145	000115-32-2
145	SELENIUM	776.4	146	007782-49-2
146	1,1,2,2-TETRACHLOROETHANE	775.8	147	000079-34-5
147	HEPTACHLORODIBENZO-P-DIOXIN	773.4	148	037871-00-4
148	PARATHION	773.3	149	000056-38-2
149	HEXACHLOROCYCLOHEXANE, TECHNICAL GRADE	772.9	150	000608-73-1
150	TRICHLOROFLUOROETHANE	772.3	151	027154-33-2
151	BROMINE	770.0	152	007726-95-6
152	AROCLOR 1268	763.8	New	011100-14-4
153	1,3-BUTADIENE	760.9	155	000106-99-0
154	HEPTACHLORODIBENZOFURAN	755.2	153	038998-75-3
155	TRIFLURALIN	754.2	154	001582-09-8
156	1,2,3,4,6,7,8,9-OCTACHLORODIBENZOFURAN	742.6	156	039001-02-0
157	AMMONIA	741.2	157	007664-41-7
158	2-METHYLNAPHTHALENE	726.8	158	000091-57-6
159	1,4-DICHLOROBENZENE	723.4	159	000106-46-7
160	2,3,4,7,8-PENTACHLORODIBENZOFURAN	723.4	161	057117-31-4
161	1,1-DICHLOROETHANE	722.5	160	000075-34-3
162	NALED	720.4	162	000300-76-5
163	1,1,2-TRICHLOROETHANE	719.5	165	000079-00-5
164	HEXACHLOROCYCLOPENTADIENE	717.9	163	000077-47-4
165	1,2-DIPHENYLHYDRAZINE	717.6	164	000122-66-7
166	PHORATE	715.0	166	000298-02-2
167	TRICHLOROETHANE	712.3	167	025323-89-1
168	ACENAPHTHENE	710.2	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-	703.2	172	000106-44-5
173	GAMMA-CHLORDENE	701.9	174	056641-38-4
174	INDENO(1,2,3-CD)PYRENE	701.8	173	000193-39-5
175	TETRACHLOROPHENOL	696.9	176	025167-83-3
176	1,2-DICHLOROBENZENE	696.6	175	000095-50-1
177	1,2-DICHLOROETHENE, TRANS-	692.3	177	000156-60-5
178	CHLOROETHANE	687.2	178	000075-00-3
179	ALUMINUM	686.6	181	007429-90-5
180	PHENOL	686.1	179	000108-95-2
181	P-XYLENE	685.9	180	000106-42-3
182	CARBON MONOXIDE	682.2	183	000630-08-0
183	CARBON DISULFIDE	681.8	182	000075-15-0
184	2,4-DIMETHYLPHENOL	679.2	184	000105-67-9
185	DIBENZOFURAN	675.8	185	000132-64-9
186	ACETONE	673.1	186	000067-64-1
187	HEXACHLOROETHANE	669.2	187	000067-72-1
188	Butyl methyl phthalate	667.3	188	034006-76-3
189	CHLOROMETHANE	665.0	189	000074-87-3
190	HEXACHLORODIBENZOFURAN	659.7	190	055684-94-1
191	BUTYL BENZYL PHTHALATE	657.6	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	195	042934-53-2
195	CRESOL, ORTHO-	652.4	194	000095-48-7
196	HEXACHLORODIBENZO-P-DIOXIN	651.3	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	646.4	199	000120-82-1
200	ETHOPROP	643.5	200	013194-48-4
201	TETRACHLORODIBENZO-P-DIOXIN	641.0	201	041903-57-5
202	BROMOFORM	634.3	202	000075-25-2
203	PENTACHLORODIBENZOFURAN	631.3	203	030402-15-4
204	1,3-DICHLOROBENZENE	627.7	204	000541-73-1
205	PENTACHLORODIBENZO-P-DIOXIN	625.4	205	036088-22-9
206	N-NITROSODIPHENYLAMINE	624.7	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	617.5	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	214	010045-97-3
212	Chromic Acid	609.9	214	007738-94-5
214	NITRITE	608.9	216	014797-65-0
215	2-BUTANONE	608.3	212	000078-93-3
216	1,2-DICHLOROETHYLENE	608.0	213	000540-59-0
217	POTASSIUM-40	607.5	218	013966-00-2
218	DINITROTOLUENE	607.2	219	025321-14-6
219	SILVER	605.4	217	007440-22-4
220	COAL TAR PITCH	605.2	221	065996-93-2
221	NITRATE	605.1	220	014797-55-8
222	THORIUM-227	604.9	222	015623-47-9
223	ARSENIC ACID	604.3	223	007778-39-4
224	FORMALDEHYDE	604.2	241	000050-00-0
225	ARSENIC TRIOXIDE	603.8	224	001327-53-3
226	BENZOPYRENE	603.4	225	073467-76-2
227	CHLORDANE, TECHNICAL	602.5	226	012789-03-6
228	STROBANE	602.5	227	008001-50-1
229	4-AMINOBIPHENYL	602.4	228	000092-67-1
229	PYRETHRUM	602.4	228	008003-34-7
231	ARSINE	602.4	230	007784-42-1
231	DIMETHOATE	602.4	230	000060-51-5
233	CARBOPHENOTHION	601.9	233	000786-19-6
234	ALPHA-CHLORDENE	601.4	234	056534-02-2
234	IODINE-131	601.4	234	010043-66-0
234	MERCURIC CHLORIDE	601.4	234	007487-94-7
234	SODIUM ARSENITE	601.4	234	007784-46-5
234	URANIUM-233	601.4	234	013968-55-3
239	ANTIMONY	600.7	232	007440-36-0
240	DIBROMOCHLOROMETHANE	599.5	239	000124-48-1
241	CRESOLS	596.7	240	001319-77-3
242	DICHLOROBENZENE	594.9	242	025321-22-6
243	2,4-D ACID	594.3	243	000094-75-7
244	2-CHLOROPHENOL	590.6	244	000095-57-8
245	BUTYLATE	589.8	245	002008-41-5
246	PHENANTHRENE	585.2	246	000085-01-8
247	DIMETHYL FORMAMIDE	585.2	247	000068-12-2
248	4-NITROPHENOL	579.4	248	000100-02-7
249	DIURON	578.7	249	000330-54-1
250	TETRACHLOROETHANE	576.4	250	025322-20-7
251	DICHLOROETHANE	567.4	251	001300-21-6
252	ETHYL ETHER	564.9	252	000060-29-7
253	DIMETHYLANILINE	561.7	254	000121-69-7
254	PYRENE	561.3	253	000129-00-0
255	1,3-DICHLOROPROPENE, CIS-	560.5	255	010061-01-5
256	1,2,3,4,6,7,8-HEPTACHLORODIBENZO-P-DIOXIN	558.6	256	035822-46-9
257	PHOSPHINE	555.2	257	007803-51-2
258	TRICHLOROBENZENE	554.9	258	012002-48-1
259	2,6-DINITROTOLUENE	554.0	259	000606-20-2
260	FLUORIDE ION	549.0	260	016984-48-8
261	1,2,3,4,6,7,8-HEPTACHLORODIBENZOFURAN	548.5	261	067562-39-4
262	PENTAERYTHRITOL TETRANITRATE	548.1	262	000078-11-5
263	1,3-DICHLOROPROPENE, TRANS-	547.6	263	010061-02-6
264	ACRYLONITRILE	543.0	264	000107-13-1
265	BIS(2-ETHYLHEXYL)ADIPATE	542.2	265	000103-23-1
266	CARBAZOLE	538.7	266	000086-74-8
267	METOLACHLOR	538.1	267	051218-45-2
268	2-CHLOROANILINE	537.9	268	000095-51-2
269	1,2,3-TRICHLOROPROPANE	535.9	269	000096-18-4
270	CARBARYL	535.4	270	000063-25-2
271	1,2-DICHLOROETHENE, CIS-	534.5	271	000156-59-2
272	STYRENE	528.1	273	000100-42-5
273	METHYL ISOBUTYL KETONE	527.6	272	000108-10-1
274	THALLIUM	524.7	274	007440-28-0
275	1,2,3,7,8,9-HEXACHLORODIBENZOFURAN	524.0	275	072918-21-9

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

CAS #= Chemical Abstracts Service Registry Number

Contact Information

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