Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The National Registry of Environmental Professionals (NREP) is a the largest U.S. non-governmental environmental accrediting organization, and is recognized by the US Department of Energy and Environmental Protection Agency. NREP has about 12,000 members worldwide, including managers, technicians, and other professionals working on operations and management related to regulatory matters such as compliance with air, soil and water pollution regulations.