(1) A territory located within reasonable proximity to a fire protection district and not within the boundaries of a city, town, or other fire protection district may be annexed to the fire protection district by petition of fifteen percent of the qualified registered electors residing within the territory proposed to be annexed. Such territory may be located in a county or counties other than the county or counties within which the fire protection district is located. The petition shall be filed with the fire commissioners of the fire protection district and if the fire commissioners concur in the petition they shall file the petition with the county auditor of the county within which the territory is located. If this territory is located in more than one county, the original petition shall be filed with the auditor of the county within which the largest portion of the territory is located, who shall be designated as the lead auditor, and a copy shall be filed with the auditor of each other county within which such territory is located. Within thirty days after the date of the filing of the petition the auditor shall examine the signatures on the petition and certify to the sufficiency or insufficiency of the signatures. If this territory is located in more than one county, the auditor of each other county who receives a copy of the petition shall examine the signatures and certify to the lead auditor the number of valid signatures and the number of registered voters residing in that portion of the territory that is located within the county. The lead auditor shall certify the sufficiency or insufficiency of the signatures. After the county auditor has certified the sufficiency of the petition, the county legislative authority or authorities, or the boundary review board or boards, of the county or counties in which such territory is located shall consider the proposal under the same basis that a proposed incorporation of a fire protection district is considered, with the same authority to act on the proposal as in a proposed incorporation, as provided under chapter 52.02 RCW. If the proposed annexation is approved by the county legislative authority or boundary review board, the board of fire commissioners shall adopt a resolution requesting the county auditor to call a special election, as specified under RCW 29A.04.330, at which the ballot proposition is to be submitted. No annexation shall occur when the territory proposed to be annexed is located in more than one county unless the county legislative authority or boundary review board of each county approves the proposed annexation.