Indiana Code Title 8. Utilities and Transportation § 8-3-22-8

Sec. 8. (a) The states of Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, and Wisconsin are eligible to join this compact.

(b) Upon approval of the commission, according to its bylaws, other states may also be declared eligible to join the compact.

(c) For an eligible party state, this compact is effective when that state's legislature enacts the compact into law.  However, the compact does not become initially effective until enacted into law by any three (3) party states incorporating the provisions of this compact into the laws of those states.

(d) Amendments to the compact become effective upon their enactment by the legislatures of all compacting states.