An environmental management system (EMS) is "a system which integrates policy, procedures and processes for training of personnel, monitoring, summarizing, and reporting of specialized environmental performance information to internal and external stakeholders of a firm".
The most widely used standard on which an EMS is based is International Organization for Standardization (ISO) 14001. Alternatives include the EMAS.
The goals of EMS are to increase compliance and reduce waste:
An environmental management system (EMS):

An EMS follows a Plan-Do-Check-Act, or PDCA, Cycle. The diagram shows the process of first developing an environmental policy, planning the EMS, and then implementing it. The process also includes checking the system and acting on it. The model is continuous because an EMS is a process of continual improvement in which an organization is constantly reviewing and revising the system.
This is a model that can be used by a wide range of organizations – from manufacturing facilities to service industries to government agencies.
Environmental Management Systems can be accredited under ISO 14001.
An EMS can also be classified as:
English management summary of: Gastl, R 2009, Kontinuierliche Verbesserung im Umweltmanagement - die KVP-Forderung der ISO 14001 in Theorie und Unternehmenspraxis, 2nd Edition, vdf, Zurich-Switzerland