| DRDow Reichhold Specialty Latex LLC (closed) | Dover | — | ◇ UNVERIFIED |
| DEDupont Electronic Materials Cmp, Llc-building 8 | Newark | — | ◇ UNVERIFIED |
| DHDupont Hay Road Sludge Drying Site | Wilmington | — | ◇ UNVERIFIED |
| EPEdgewell Personal Care - Plant 4 | Dover | — | ◇ UNVERIFIED |
| EIE I Dupont De Nemours - Christiana Lab | Wilmington | — | ◇ UNVERIFIED |
| EIE I Dupont De Nemours - Glasgow Site | Newark | — | ◇ UNVERIFIED |
| EIE I Dupont De Nemours - Holly Run Plant | Newport | — | ◇ UNVERIFIED |
| EMEssential Minerals LLC - Lambson Plant | New Castle | — | ◇ UNVERIFIED |
| FDFamily Dollar #11978 | Newark | — | ◇ UNVERIFIED |
| GEGalloway Electric CO INC | Newark | — | ◇ UNVERIFIED |
| GEGe Energy (usa) LLC | Newark | — | ◇ UNVERIFIED |
| GSGreentree Spray Technologies LLC | Seaford | — | ◇ UNVERIFIED |
| HIHalosil International, INC. | New Castle | — | ◇ UNVERIFIED |
| HCHarmony Cleaners | Newark | — | ◇ UNVERIFIED |
| HTHigh Tech Auto Body INC | Wilmington | — | ◇ UNVERIFIED |
| HSHockessin Sunoco Service Station 0004 743 - 7427 Lancaster Pike, Hockessin | Hockessin | — | ◇ UNVERIFIED |
| HIHoneywell International Inc-claymont | Claymont | — | ◇ UNVERIFIED |
| IAInvista Applied Research Centre | New Castle | — | ◇ UNVERIFIED |
| JTJust Tires - Goodyear | Wilmington | — | ◇ UNVERIFIED |
| KDKaneka Delaware Corporation | Delaware City | — | ◇ UNVERIFIED |
| LCLanxide Corporation | Newark | — | ◇ UNVERIFIED |
| MTMillsboro Tce | Millsboro | — | ◇ UNVERIFIED |
| MIMirror Image on Rd 2 Box 12a, Hartly | Hartly | — | ◇ UNVERIFIED |
| MPModern Press INC | Wilmington | — | ◇ UNVERIFIED |
| NANewark Armed Forces Reserve Center | Newark | — | ◇ UNVERIFIED |
| PBPeppers Body Works | Dover | — | ◇ UNVERIFIED |
| PIPpg Industries Architectural Finishes | Dover | — | ◇ UNVERIFIED |
| PCPtfe Compounds INC | New Castle | — | ◇ UNVERIFIED |
| RARohm and Haas Electronic Materials Cmp INC | Newark | — | ◇ UNVERIFIED |
| SPSchering Plough Animal Health - 369 West Dupont Highway, Millsboro | Millsboro | — | ◇ UNVERIFIED |
| S1Shell 1416 - Talleyville | Wilmington | — | ◇ UNVERIFIED |
| SHSiemens Healthcare Diagnostics - Rt 896, Glasgow | Newark | — | ◇ UNVERIFIED |
| SLSolenis, LLC | Wilmington | — | ◇ UNVERIFIED |
 Southern States/milford CO Op | Milford | — | ◇ UNVERIFIED |
| SPSpi Polyols INC. | New Castle | — | ◇ UNVERIFIED |
| SOSquare One Electric Service - 347 Fork Branch Rd, Dover | Dover | — | ◇ UNVERIFIED |
| SCStandard Chlorine of Delaware, INC. Superfund Site | New Castle | — | ◇ UNVERIFIED |
| SOState of Delaware Graphics & Printing - 604 Otis Dr, Dover | Dover | — | ◇ UNVERIFIED |
| SASumpter Auto Refinishing | Dover | — | ◇ UNVERIFIED |
| VDVerizon Dover Soc | Dover | — | ◇ UNVERIFIED |
| WLWilmington Leather Coatings | New Castle | — | ◇ UNVERIFIED |
| ALAir Liquide Advanced Separations | Newport | 100–499 | ◐ LIKELY ACTIVE |
| BBBridgeville Branch 33 | Bridgeville | 1–19 | ◐ LIKELY ACTIVE |
| CClaymont | Claymont | 20–99 | ◐ LIKELY ACTIVE |
| FIFujifilm Imaging Colorants | New Castle | 20–99 | ◐ LIKELY ACTIVE |
| FIFujifilm Imaging Colorants | Newcastle | 20–99 | ◐ LIKELY ACTIVE |
| FIFujifilm Imaging Colorants Inc. | New Castle | 20–99 | ◐ LIKELY ACTIVE |
| ISICP Seaford | Seaford | 20–99 | ◐ LIKELY ACTIVE |
| INInternational N&H USA, Inc. | Newark | 100–499 | ◐ LIKELY ACTIVE |
| IIIntervet, Inc. Delaware Avenue | Millsboro | 20–99 | ◐ LIKELY ACTIVE |
