Fall-out shelters are permitted as principal or accessory buildings and uses in any zone. Fall-out shelters constructed above ground must conform to the setback requirements for accessory buildings in the particular zone in which they are located. Underground shelters may be constructed any place in the front, rear or side yards; but may not extend across a property line or into a public utility easement. Such shelters may contain or be contained in other structures or may be constructed separately. In addition to fall-out shelter use they may be used for any other use permitted in that zone, subject to the zoning regulations for such use, but shall not be used for any use prohibited in that zone. (Amended during the March 2009 supplement.)