Mont. Code Ann. § 90-1-101

90-1-101 . Declaration of necessity and public policy. (1) It is hereby declared to be a necessity and the public policy of the state to promote, stimulate, and encourage the planning and development of the economy of the state in order to provide for the social and economic prosperity of its citizens. Such promotion and development of industry, commerce, agriculture, labor, and natural resources of the state require that cognizance be taken of the continuing migration of people to the urban areas in search of job opportunities and the fact that Montana is making a needed transition to a diversified economy. Community planning, greater diversification of industry and attraction of additional industry, accelerated development of natural resources, expansion of existing industry, creation of new uses for agricultural products, greater emphasis on scientific research, development of new markets for the products of the state, and the attainment of a proper balance in the overall economic base, without leaving behind those who remain in rural areas, are all necessary in order to create additional employment opportunities, increase personal income, retain quality of life for rural Montana, and promote the general welfare of the people of this state.

(2) The legislature recognizes that consistency and continuity in the adoption and application of environmental rules are essential to the protection and enhancement of Montana's economic well-being, that consistency and continuity are particularly important to those persons who have made a financial commitment after completing an application for an environmental permit based on the existence of certain environmental rules, and that those persons are entitled to a reasonable expectation that requirements in such a permit will not be changed to their detriment. Therefore, when a person makes a financial commitment after having completed an application for an environmental permit, it is the policy of the state not to change the requirements for such permit to the detriment of the applicant or permittee without having first taken into account and given consideration to previous expenditures made by the applicant or permittee.

(3) The department of commerce shall be regarded as performing a governmental function in carrying out the provisions of 90-1-102 through 90-1-109 .