An environmental management system (EMS) can help companies reduce costs by decreasing waste and improving processes, gain a competitive advantage, ensure compliance with environmental regulations, and improve public image. There are three approaches to implementing an EMS: developing an in-house system, following the ISO 14001 international standard or EMAS, or pursuing external certification under these standards. External certification provides credibility and discipline that may not be achieved otherwise, and is desirable when buyers require it, to enhance reputation, or enter new markets where the environment is a priority. An effective EMS includes commitment from senior management, designating an overseer, setting policy and objectives, assessing impacts, training staff, record keeping, and auditing.