Do you sell internationally?  Are you aware of OFAC (Office of Foreign Assets Control)?

Office of Foreign Assets Control – Sanctions Programs and Information

The Office of Foreign Assets Control of the U.S. Department of the Treasury administers and enforces economic and trade sanctions based on U.S. foreign policy and national security goals against targeted foreign countries and regimes; terrorists; international narcotics traffickers; those engaged in activities related to the proliferation of weapons of mass destruction; and other threats to the national security, foreign policy, or economy of the United States.

OFAC provides a free, online application to enable to users to simultaneously search all of its sanctions lists. OFAC Sanctions Lists can be found at: www.treasury.gov/resource-center/sanctions/Pages/default.aspx

These lists include individuals and companies owned or controlled by, or acting for or on behalf of, targeted countries. It also list individuals, groups, and entities, such as terrorists and narcotics traffickers designated under programs that are not country-specific.