Montana Title 2. Government Structure and Administration § 2-9-111. Immunity from suit for legislative acts and omissions

(a) the term “governmental entity” means only the state, counties, municipalities, school districts, and any other local government entity or local political subdivision vested with legislative power by statute;

(b) the term “legislative body” means only the legislature vested with legislative power by Article V of The Constitution of the State of Montana and that branch or portion of any other local governmental entity or local political subdivision empowered by law to consider and enact statutes, charters, ordinances, orders, rules, policies, resolutions, or resolves;

(a) any tort committed by the use of a motor vehicle, aircraft, or other means of transportation; or

(b) any act or omission that results in or contributes to personal injury or property damage caused by contamination or other alteration of the physical, chemical, or biological properties of surface water or ground water, for which a cause of action exists in statutory or common law or at equity. This subsection (b) does not create a separate or new cause of action.