Superfund sites in Idaho
As of Oct 26, 2026, EPA's Superfund National Priorities List (NPL) has 6 final sites in Idaho (tied for 44th among the 50 states and DC), plus 3 proposed and 3 deleted: 12 in all. The county with the most final sites is Caribou (2). 3 of the 6 final sites have a construction completion date. The most recent addition to the final list is Mountain Home Air Force Base in Mountain Home (Aug 30, 1990). EPA last updated its NPL list on Sep 30, 2026.
Checking one address? Use the free Superfund sites near me lookup, or get the Environmental Records Report.
Map of Superfund sites in Idaho
The map shows 10 of 12 sites; the rest open with HeritageDeed Pro.
List of Superfund sites in Idaho
| Bunker Hill Mining & Metallurgical ComplexEPA ID IDD048340921 | Smelterville | Shoshone | Final NPL | Sep 8, 1983 | no | no | 54.76 |
| Eastern Michaud Flats ContaminationEPA ID IDD984666610 | Pocatello | Bannock, Power | Final NPL | Aug 30, 1990 | no | no | 57.8 |
| Idaho National Engineering Laboratory (USDOE)EPA ID ID4890008952 | Idaho Falls | Bingham, Bonneville, Butte, Clark, Jefferson | Final NPL | Nov 21, 1989 | no | no | 51.91 |
| Kerr-McGee Chemical Corp. (Soda Springs Plant)EPA ID IDD041310707 | Soda Springs | Caribou | Final NPL | Oct 4, 1989 | Sep 26, 2001 | no | 51.91 |
| Monsanto Chemical Co. (Soda Springs Plant)EPA ID IDD081830994 | Soda Springs | Caribou | Final NPL | Aug 30, 1990 | Sep 20, 2000 | no | 54.77 |
| Mountain Home Air Force BaseEPA ID ID3572124557 | Mountain Home | Elmore | Final NPL | Aug 30, 1990 | Sep 30, 1998 | no | 57.8 |
| Blackbird MineEPA ID IDD980725832 | Lemhi County | Lemhi | Proposed | proposed May 10, 1993 | no | no | 50 |
| St. Maries CreosoteEPA ID IDSFN1002095 | St. Maries | Benewah | Proposed | proposed Dec 1, 2000 | no | no | 50 |
| Arrcom (Drexler Enterprises)EPA ID IDD000800961 | Rathdrum | Kootenai | Deleted | Sep 8, 1983 | Jun 30, 1992 | Dec 23, 1992 | 29.28 |
| Pacific Hide & Fur Recycling Co.EPA ID IDD098812878 | Pocatello | Bannock | Deleted | Sep 21, 1984 | Sep 29, 1997 | Nov 4, 1999 | 42.3 |
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Every site on EPA's National Priorities List in Idaho: final, proposed and deleted. Site names, cities and counties are as EPA publishes them. Updated as of Oct 26, 2026.
Superfund sites by county
| County | Final | Proposed | Deleted | All |
|---|---|---|---|---|
| Caribou | 2 | 0 | 0 | 2 |
| Bannock | 1 | 0 | 2 | 3 |
| Bingham | 1 | 0 | 0 | 1 |
| Bonneville | 1 | 0 | 0 | 1 |
| Butte | 1 | 0 | 0 | 1 |
| Clark | 1 | 0 | 0 | 1 |
| Elmore | 1 | 0 | 0 | 1 |
| Jefferson | 1 | 0 | 0 | 1 |
| Power | 1 | 0 | 0 | 1 |
| Shoshone | 1 | 0 | 0 | 1 |
| Benewah | 0 | 1 | 0 | 1 |
| Kootenai | 0 | 0 | 1 | 1 |
| Lemhi | 0 | 1 | 0 | 1 |
| Valley | 0 | 1 | 0 | 1 |
Counties as named in EPA records. 2 sites that EPA lists in more than one county are counted in each, so the column totals can exceed the state total.
Other EPA environmental records in Idaho
The Superfund list is one of several federal lists an environmental records search reviews. Statewide counts from the same federal EPA records the Environmental Records Report searches:
| Record | ID | What it counts |
|---|---|---|
| Other Superfund sites not on the NPL | 191 | Sites in EPA's Superfund records that are not on the National Priorities List, such as removal-only sites and sites where no further federal remedial action is planned. |
| Leaking underground storage tank releases | 1,577 | 67 open, 1,510 closed with no further action. Later releases may not be included. |
| Underground storage tank facilities | 5,498 | 3,225 open tanks at these facilities. |
| EPA brownfield properties | 352 | Properties that received EPA Brownfields grant funding for assessment or cleanup. State-only brownfield and voluntary cleanup programs are not included. |
| Counties in EPA radon Zone 1 | 19 of 44 | Zone 1 means a predicted average indoor radon screening level above 4 pCi/L; 20 counties are Zone 2 (2 to 4) and 5 Zone 3 (below 2). EPA's county map is a screening guide; only a test measures a building's level. |
What the NPL statuses mean
- Final NPL
- A site is placed on the National Priorities List after Hazard Ranking System screening, a public comment period on the proposal, and EPA's response to the comments. EPA calls the NPL primarily an information and management tool that guides which sites warrant further investigation.
- Proposed
- EPA has proposed the site for the NPL and published the proposal for public comment; it is not on the final list until EPA adds it after addressing the comments.
- Deleted
- EPA may delete a final NPL site when it determines that no further response is required to protect human health or the environment (40 CFR 300.425(e)). Deleted sites remain eligible for further Superfund-financed remedial action if future conditions warrant it.
- Partial deletion
- EPA can delete part of a site from the NPL while the rest stays listed. The table marks sites whose EPA record shows a partial deletion.
- Construction complete
- EPA records a construction completion date for a site. After it, EPA's post construction work can continue: operation and maintenance, institutional controls, five-year reviews, and in time deletion from the NPL.
- HRS score
- The Hazard Ranking System score is EPA's screening score from initial investigations. EPA says HRS scores do not determine the priority in funding remedial response actions.
What a nearby Superfund site means for a buyer
EPA says inclusion of a site on the NPL "does not in itself reflect a judgment of the activities of its owner or operator, it does not require those persons to undertake any action, nor does it assign liability to any person". A listing marks a release EPA is investigating or cleaning up; whether it affects a particular property depends on where the contamination goes.
The 2002 amendments to CERCLA (the Superfund law) created the bona fide prospective purchaser protection. EPA explains that a person may now acquire property knowing of contamination if they acquire it after January 11, 2002, do not impede the cleanup, and meet the statute's criteria, which include carrying out "all appropriate inquiries" before buying and taking "reasonable steps" afterwards.
For property bought for residential or similar use by a non-commercial buyer, the statute treats "a facility inspection and title search that reveal no basis for further investigation" as meeting that inquiry requirement (42 U.S.C. 9601(35)(B)(v)). EPA's 1991 policy toward owners of residential property at Superfund sites was issued "to relieve residential owners of the fear that they might be subject to an enforcement action involving contaminated property, even though they had not caused the contamination".
The ASTM E1527-21 standard for Phase I environmental site assessments reviews NPL sites within 1 mile of a property and deleted NPL sites within half a mile. The Environmental Records Report searches those lists, and the other federal lists, to the same distances for any US address.
Prefer a quick look first? The free Superfund sites near me lookup lists the NPL sites within 3 miles of any address.
Questions about Superfund sites in Idaho
How many Superfund sites are in Idaho?
EPA's National Priorities List has 6 final sites, 3 proposed sites and 3 deleted sites in Idaho, 12 in all. EPA's Superfund records also hold 191 other Idaho sites that are not on the NPL.
Where are the Superfund sites in Idaho?
By county, the most NPL sites (final, proposed and deleted) are in Caribou (2), Bannock (3), Bingham (1), Bonneville (1), Butte (1). 14 Idaho counties have at least one NPL site. The table on this page lists every site with its city, status and dates.
What is the newest Superfund site in Idaho?
The most recent site added to the final NPL in Idaho is Mountain Home Air Force Base (Mountain Home), listed Aug 30, 1990. The most recently proposed site still awaiting a final decision is Stibnite/Yellow Pine Mining Area (Yellow Pine), proposed Sep 13, 2001.
What does deleted from the NPL mean?
EPA may delete a final NPL site when it determines that no further response is required to protect human health or the environment (40 CFR 300.425(e)). EPA says deleted sites remain eligible for further Superfund-financed remedial action if future conditions warrant it, so a deleted site is still worth knowing about.
How can I check whether a Idaho property is near a Superfund site?
Enter the address in HeritageDeed's free Superfund sites near me lookup, which lists NPL sites within 3 miles of the address. The Environmental Records Report adds every federal list within the ASTM E1527-21 search distances (NPL sites to 1 mile, deleted NPL sites to half a mile), with a site map.
Does a Superfund site nearby mean a property is contaminated?
No. EPA says placing a site on the NPL does not in itself reflect a judgment of the activities of its owner or operator and does not assign liability to any person. A listing says where EPA is investigating or cleaning up a release, not whether contamination reaches a given property; groundwater direction, the type of contamination and the cleanup stage matter, and an environmental professional can assess a specific property.
States bordering Idaho
Superfund sites in every state
About this data
HeritageDeed refreshes this page every night from federal EPA records: names, cities, counties, statuses and dates are EPA's. This page was last updated on Oct 26, 2026.
Legal references
- 42 U.S.C. 9601(35)(B)(v), site inspection and title search