(1) A joint agency formed for the purposes provided in this article is a public body politic and corporate and the powers conferred by this act are considered to be the performance of an essential public function.

    (2) Any combination of 2 or more municipalities described in section 31 may incorporate a joint agency by the adoption of articles of incorporation by resolution of the governing body of each municipality. The fact of adoption shall be endorsed on the articles of incorporation by the chief executive officer and clerk of the municipality, in form substantially as follows:

The foregoing articles of incorporation

were adopted by the _____________________________________________,

of the ____________________, of __________________________ county,

Michigan, at a meeting duly held on the ______________________ day

of _____________, _____.

__________________________________________

__________________________________ of said

__________________________________________

__________________________________ of said

_________________________________________.

(3) The articles of incorporation shall be published at least once in a newspaper or newspapers designated in the articles and generally circulating within the area of each municipality. One printed copy of the articles of incorporation, certified as a true copy by the person or persons designated in the articles, with the date and place of the publication, shall be filed with the county clerk or clerks of the county or counties in which the incorporating municipalities are located and the secretary of state. The incorporation of the joint agency shall become effective at the time provided in the articles of incorporation. The validity of the joint agency incorporation shall be conclusive unless questioned in a court of competent jurisdiction within 60 days after the filing of certified copies with the county clerk or clerks and the secretary of state.

    (4) The articles of incorporation shall state the name of the joint agency, the names of the various incorporating municipalities, the purpose or purposes for which it is created, the powers, duties, and limitations of the joint agency and its officers, the method of selecting its governing body, officers, and employees, the person or persons who are charged with the responsibility for causing the articles of incorporation to be published and filed or who are charged with the responsibility in connection with the incorporation of the joint agency, the place of publication, and all other matters which the incorporating municipalities consider advisable, all of which shall be subject to article 3 of this act and of the constitution and laws of the state.

    (5) The board of commissioners of a joint agency may, by resolution, authorize the establishment of 1 or more classes of associate membership in the joint agency. A municipality admitted as an associate member shall have participatory and other rights and obligations as provided in the resolution establishing the associate membership class or classes.

    (6) A municipality described in section 31 which did not join in the original incorporation of a joint agency may become a member or an associate member of the joint agency by the adoption of a resolution by the governing body of the municipality and by a resolution unanimously adopted by all members of the board of commissioners of the joint agency. The resolution of the board of commissioners may provide that a municipality shall become a member or an associate member at a future date or upon the occurrence of a future event and may provide further that the decision of the board of commissioners may not be revoked without the consent of the governing body of the municipality being added as a member or associate member. Upon the addition of a new member or associate member, the articles of incorporation shall be conformed by the board of commissioners to show the addition of the new member or associate member and, if the municipality is being added as an associate member, the rights and obligations of the municipality as an associate member. Other amendments may be made to the articles of incorporation if adopted by the governing body of each municipality of which the joint agency is composed. An amendment shall be endorsed, published and certified and printed copies filed in the same manner as the original articles of incorporation, except an amendment showing only the addition of a new member or associate member and the rights and obligations of a new associate member need not be published.