​Jan Mares was previously a business liaison and deputy director at the Private Sector Office of the Department of Homeland Security (DHS). During the Reagan administration, Mares was an assistant secretary of commerce for import administration and a senior policy analyst at the White House, where he was involved with environment, energy, trade, and technology issues. He also served as assistant secretary of energy for international affairs and energy emergencies; assistant secretary of energy for policy, safety and environment; and assistant secretary of energy for fossil energy. For six months he was the acting under secretary of energy. Before entering federal service, Mares was with Union Carbide Corporation for 18 years, half in the Law Department, working on antitrust compliance and purchasing issues, and half in its chemical business, including leading an effort for three years to create a chemicals joint venture with a Middle East government company and being the operations/profit manager for several groups of industrial chemicals. Subsequent to his service in the Reagan administration, he worked with the Washington, DC, law firm Shaw Pittman, the Synthetic Organic Chemical Manufacturers Association, and the EOP Group (a Washington DC environment, energy, and budget consulting firm).