EPA is responsible for implementing federal environmental statutes in Indian country. In the absence of a federally approved tribal program, EPA retains program implementation authority. Currently, EPA maintains responsibility for the implementation of the vast majority of federal environmental statutes in Indian country.

The EPA's Direct Implementation of Federal Environmental Programs in Indian Country document describes EPA’s direct implementation responsibilities and activities under nine major federal environmental statutes and for emergency response activities. Each section describes the key direct implementation responsibilities that EPA retains.