Orrington selectmen voted 3 to 2 Tuesday night to fire Town Manager Joan Gibson, whose first day on the job was March 11. Gibson, 58, of Levant was the third person to leave the position in less than a year. Her firing was effective immediately. She did not attend Tuesday night’s meeting, according to a video of the meeting posted on Facebook. No one has yet been appointed to serve as interim town manager. The firing is expected to further divide the community already at odds over a proposed $3.5 million public safety building that voters rejected in December and the elimination of a community policing program with the Penobscot County Sheriff’s Office.