| Abbreviation | Definition |
|---|---|
| OCRM | Ocean Coastal Resource Management |
| OCWA | Ontario Clean Water Agency |
| ODC | Ozone Depleting Chemical |
| ODEQ | Oregon Department of Environmental Quality |
| ODI | Out-Door Incident |
| ODP | Ozone Depletion Potential |
| ODWS | Ontario Drinking Water Standard(s) |
| OEA | Office of Environmental Adjudication |
| OEA | Office of Environmental Affairs |
| OEA | Office of Environmental Analysis |
| OEA | Office of Environmental Assistance |
| OEA | The Office Of Environmental Assistance |
| OEABCM | Other Effective Area-Based Conservation Measures |
| OEBI | Other Environmental Benefits Index |
| OEBR | Ontario Environmental Bill Of Rights |
| OEC | Office of Environmental Coordination |
| OEC | Ohio Environmental Council |
| OEC | Oregon Environmental Council |
| OECC | Overseas Environmental Cooperation Center |
| OECC | Oxford Environmental Consolidation Cell |