| Environmental consulting firms | Due diligence, investigations, permitting, compliance, restoration and remediation consulting | Lead or support defined technical scopes suited to their qualifications |
| Independent specialists | Hydrogeology, ecology, geology, industrial hygiene, professional review and other niche expertise | Contribute specialized analysis or technical direction to a project team |
| Field and specialty contractors | Sampling, drilling, monitoring, site services, construction-related environmental work | Provide crews, equipment and field execution under appropriate agreements |
| Laboratories and suppliers | Analytical testing, equipment, instrumentation, materials and logistics | Support the field and analytical requirements of specific assignments |
| Other related professionals | Qualified services that connect to environmental project needs | Considered when a project requires their experience or resources |