The Office of Environmental Enforcement (OEE) within the Environmental Protection Agency (EPA) has developed the National Priority Sites (NPS) system which ranks licensed industrial and waste licensed facilities in order of priority for enforcement. In this way, the OEE focuses its efforts and resources on those sites which perform poorly from an enforcement point of view. The NPS list was first published by the EPA in July 2017 and since then has been published on a quarterly basis. Since its inception, the NPS has driven environmental improvements at sites in terms of their level of compliance and environmental performance. This project will assess the NPS system in use currently and examine what impact it has had on the behaviour of licensees and also improving overall licence compliance rates. Similarly, the views of OEE staff will also be sought as part of the work.