PORTLAND, Maine - Wyman Briggs, a Coast Guard preparedness specialist, gives an overview of the Spill Of National Significance 2010 exercise at a public, open house here, March 4, 2010. The SONS 2010 exercise takes place every three years throughout the country and provides an opportunity for emergency responders to practice the National Incident Command structure that is used when responding to an incident that impacts public health and the environment. The focus of SONS 2010 will be to implement a new SONS Response Policy, to define the roles and responsibilities for the national level command, and to exercise regional and local oil spill response policies, plans, and procedures. Coast Guard video by Petty Officer 2nd Class Etta Smith.