| Abbreviation | Definition |
|---|---|
| CHESS | Council for Health and Environmental Safety of Soils |
| CHIEF | Craig Hospital Inventory of Environmental Factors |
| CHP | Centre for Health Protection |
| CHPI | Computers to Help People, Incorporated |
| CHRA | Chemical Health Risk Assessment |
| CHS | Code for Sustainable Homes |
| CI | Catalyze Investment |
| CI | Chemical Impurities |
| CIAA | Clean Indoor Air Act |
| CIBER | Center for Integrated Biological and Environmental Research |
| CICERO | Center for International Climate and Environmental Research Oslo |
| CIE | Community Industrial Exposure |
| CIEA | California Indian Environmental Alliance |
| CIEC | Certified Indoor Environmental Consultant |
| CIEE | California Institute for Energy and Environment |
| CIEEM | Chartered Institute for Ecological and Environmental Management |
| CIEEM | Chartered Institute for Ecology and Environmental Management |
| CIEEM | Chartered Institute of Ecology and Environmental Management |
| CIEF | Construction Industry Environmental Forum |
| CIEH | Chartered Institute of Environmental |