An outside investigator is looking into allegations that Washington County Chair Kathryn Harrington created a hostile work environment that led the embattled head of the county’s sewer agency to tender her resignation last month.

Former Clean Water Services CEO Diane Taniguchi-Dennis made the allegations in a May 8 email sent to the sewer board, saying she could no longer tolerate being “disrespected, humiliated” and “belittled” by Harrington, who previously faced similar allegations from county employees.