Since January 8, 2009, United States (U.S.) and foreign flagged ships operating in the waters of the U.S. have been subject to MARPOL Annex VI. The Marine Environmental Protection Committee (MEPC) of the International Maritime Organization (IMO) adopted amendments to Annex VI and the nitrogen oxides (NOx) Technical Code, collectively referred to as Annex VI (Revised). Annex VI (Revised) entered into force on July 1, 2010. These amendments include significant and progressive limits for sulfur oxide (SOx) and NOx emissions from marine engines and for the first time addressed emissions of Particulate Matter (PM). The amendments replaced the SOx Emissions Control Areas (SECA) by introducing the concept of Emission Control Areas (ECA) for SOx, NOx, and PM.