The U.S. Department of Labor's Occupational Safety and Health Administration (OSHA) recently published its Guide to Restroom Access for Transgender Workers. According to the Williams Institute at the University of California-Los Angeles, an estimated 700,000 adults in the United States are transgender--meaning their internal gender identity is different from the sex they were assigned at birth (e.g., the sex listed on their birth certificate).
OSHA's Sanitation standards require employers to provide their employees with toilet facilities. Under this new guide for transgender workers, OSHA recommends that all employees should be permitted to use sanitary facilities that correspond with their gender identity. For example, a person who identifies as a man should be permitted to use men's restrooms, and a person who identifies as a woman should be permitted to use women's restrooms. Furthermore, OSHA provides additional recommendations. Best practices include single-occupancy gender-neutral (unisex) facilities and use of multiple-occupant, gender-neutral restroom facilities with lockable single occupant stalls.
Under these best practices no employee should be required to use a segregated facility apart from other employees because of their gender identity or transgender status.