Industries List
| Name | Province | City | |
|---|---|---|---|
| OPP UHTHOFF Firing Range - Ontario Provincial Police | Ontario | Orillia | |
| Opta Nanticoke Facility - Opta Inc. | Ontario | Nanticoke | |
| Opta Regina Facility - Opta Inc. | Saskatchewan | Regina | |
| Opta Waterdown Inc. - Opta Waterdown Inc. | Ontario | Waterdown | |
| Orangeville - Holmes Agro | Ontario | Orangeville | |
| Orangeville Compound - Geon Performance Solutions | Ontario | Orangeville | |
| Orangeville Plasticizer - Geon Performance Solutions | Ontario | Orangeville | |
| Orangeville Water Pollution Control Plant - Town of Orangeville | Ontario | Orangeville | |
| Orca Sand and Gravel - Polaris Materials Corporation | British Columbia | Port McNeil | |
| Oregon Tool Canada - Oregon Tool Canada Ltd. | Ontario | Guelph |
