Natrona County, WY
The federal environmental record for Natrona County (population 79,941): what is on file, where it is, and what remains open. Sources and retrieval dates are on the methodology page.
1
Superfund NPL sites
4
federal cleanup sites
0
PFAS-detecting water systems
9
TRI facilities
32
open tank releases
Superfund NPL sites
| Site | City | Status | Listed |
|---|---|---|---|
| Mystery Bridge Rd/U.S. Highway 20 | Evansville | deleted | 08/30/1990 |
Drinking water: PFAS testing
No public water system serving Natrona reported a PFAS detection in the UCMR5 national testing round. Systems serving under 3,300 people were only sampled in part, so absence from this table is not proof of absence in the water.
Facilities reporting toxic releases (2024)
9 facilities in Natrona filed TRI reports for 2024, totalling 45k lb released.
| Facility | City | Top chemicals | Total released |
|---|---|---|---|
| HF SINCLAIR CASPER REFINING LLC | CASPER | Benzene, Ethylene | 18k lb |
| CHAMPIONX-EVANSVILLE PLANT 108 | EVANSVILLE | Methanol, Toluene | 13k lb |
| CUSTOM FIBERGLASS INC | CASPER | Styrene | 6k lb |
| EXCAL INC. | MILLS | Zinc (fume or dust), Lead | 4k lb |
| TALLGRASS MIDSTREAM LLC - CASPER GAS PLANT & COMPRESSOR STAT | CASPER | n-Hexane, Benzene | 4k lb |
| KNIFE RIVER CASPER | CASPER | Nitrate compounds (water dissociable; reportable only when in aqueous solution), Polycyclic aromatic compounds | 14 lb |
| HALLIBURTON CASPER BAROID | EVANSVILLE | - | 0 lb |
| HALLIBURTON CASPER FIELD CAMP | EVANSVILLE | Lead And Lead Compounds | 0 lb |
| JOY GLOBAL EVANSVILLE WY | EVANSVILLE | - | 0 lb |
Underground fuel tanks
EPA's UST Finder records 493 tank facilities in Natrona: 170 tanks in service and 1,114 closed. 178 fuel releases are on record, of which 32 remain open. Open releases are cleanups that have not reached "no further action".
Radon
EPA maps Natrona as Zone 1, the highest predicted indoor radon levels (over 4 pCi/L average). Radon and air quality are covered in depth on lung.com.
The record for one specific address
County figures blur what matters: distance. The Address Environmental Report runs these same federal datasets against one address and reports every site, tank, polluter and water result around it, with distances, in about a minute.
Get the report - $39All federal cleanup sites on file
The wider Superfund enterprise inventory (SEMS) for Natrona, including sites assessed but never listed. Presence here records that EPA had reason to look, not a finding of danger.
- FORMER CASPER ARMY AIRFIELD/NATRONA COUNTY INTERNATIONAL AIRPORTCASPER
- MYSTERY BRIDGE RD/U.S. HIGHWAY 20EVANSVILLE
- SALT CREEK ABANDONED DRUMSCASPER
- WESTERN AREA POWER ADMIN CASPER FIELD BRMILLS