Me. Stat. tit. 37-B § 1009
Any individual, partnership, association, corporation, municipal corporation or state or any of its political subdivisions engaged in, or preparing to engage in, the manufacture, transportation or storage of any product to be used in the preparation of the United States or of any of the states for defense or for war, or in the prosecution of war by the United States, or with preparations and plans for emergency management, or with the execution of these preparations and plans under chapter 13, or the manufacture, transportation, distribution or storage of gas, oil, coal, electricity or water, or any individual, partnership, association, corporation, municipal corporation or state or any of its political subdivisions operating a public utility, whose property, except where it fronts on water or where there are entrances for railway cars, vehicles, persons or things, is surrounded by a fence or wall, or a fence or wall and buildings, may post around that property at each gate, entrance, dock or railway entrance and every 100 feet of waterfront a sign reading "No Entry Without Permission." Any person who intentionally enters upon premises posted in that manner without the permission of the owner is guilty of a Class E crime. [2001, c. 614, §28(AMD).]
37-B M.R.S. § 1009