National Response System Law and Legal Definition

National Response System (NRS) is the U.S. government's mechanism for emergency and immediate response to discharges of oil and the release of chemicals into the navigable waters or environment of the U.S. and its territories. The NRS initially focused on oil spills and selected hazardous polluting substances discharged into the environment. However, now it responds to hazardous substances and wastes released to all types of media.

The NRS functions through a network of interagency and inter-government relationships. The NRS coordinates response actions by all levels of government. The NRS is capable of expanding or contracting to accommodate the response effort required by the size or complexity of the discharge or release. [40 CFR 300.5].