Security workers at Seattle Art Museum have moved to join a union, part of a growing movement of museum employees across the nation seeking unionization to address concerns including wages, benefits and working conditions during the pandemic. Last month, more than 70% of SAM’s 75 internal security workers submitted authorization cards to their employer signaling they would like to be represented by the International Union of Painters and Allied Trades Local 116. The effort, which has been underway for more than six months, was prompted by concerns over an unsafe environment during the COVID-19…