" Ports, waterways, and vessels handle billions of dollars in cargo annually and an attack on this maritime transportation system could impact the global economy. November 2012 marks the 10-year anniversary of MTSA, which required a wide range of security improvements. DHS is the lead federal department responsible for implementing MTSA and it relies on its component agencies, such as the Coast Guard and CBP, to help implement the act. The Coast Guard is responsible for U.S. maritime security interests and CBP is responsible for screening arriving vessel crew and cargo. This testimony summarizes GAO's work on implementation of MTSA requirements over the last decade and addresses (1) progress the federal government has made in improving maritime security and (2) key challenges that DHS and its component agencies have encountered in implementing maritime security-related programs. GAO was unable to identify all related federal spending, but estimated funding for certain programs. For example, from 2004 through May 2012, CBP obligated over $390 million to fund its program to partner with companies to review the security of their supply chains. This statement is based on GAO products issued from August 2002 through July 2012, as well as updates on the status of recommendations made and budget data obtained in August 2012. "