Margaret (Peg) Seminario is director of occupational safety and health for the AFL-CIO. She has worked for the AFL-CIO since 1977, and since 1990 has been responsible for directing the AFL‑CIO's program on safety and health. She is a nationally recognized occupational safety and health leader and expert with extensive experience in safety and health policy, regulation, and legislation.  

At the AFL-CIO, Seminario has led the federation’s efforts to seek improved safety and health protections for workers, participating in dozens of rule makings before the Occupational Safety and Health Administration and organizing broad-based campaigns on the right to know about chemical hazards and ergonomic protections. She was one of the leaders in labor’s efforts to enact the 9/11 Health and Compensation Act to provide health care and compensation to responders sick from exposures at the World Trade Center. Seminario is the AFL-CIO’s lead organizer of Workers Memorial Day, observed annually on April 28, to remember workers killed, injured and diseased on the job and to highlight the need for improved job safety protections.  

Seminario has served on numerous federal agency and scientific advisory committees and participated in international safety and health work through the International Labor Organization, the Organization for Economic Cooperation and Development and international trade union organizations.  

She holds a Master of Science degree in industrial hygiene from the Harvard T.H. Chan School of Public Health and a Bachelor of Arts in biological sciences from Wellesley College.