The Great Lakes Geographic Annex (CANUSLAK Plan) is an operational annex to the bilateral Joint Marine Pollution Contingency Plan between the United States and Canada established to ensure coordinated planning, preparedness, and response to a harmful substance incident in the contiguous waters of the two nations. The CANUSLAK Annex covers the Great Lakes boundary between Canada and the United States, defines the CANUSLAK Joint Response Team (JRT), and is regularly tested and improved on in an ongoing series of CANUSLAK exercises. Its purpose is to augment and link the pollution response systems and plans in each nation to facilitate an efficient joint response to a cross border spill.