Ensuring Scanned Containers Arrive in Ports Efficiently Act of 2012 - Amends the Security and Accountability For Every Port Act of 2006 to require the Secretary of Homeland Security (DHS), on order to extend the date after which all containers loaded on a vessel destined for the United States must be scanned in a foreign port, to submit a feasibility study, including a cost-benefit analysis and an available systems assessment, on meeting such requirement.