New Law Bolsters Efforts to Make Ocean-Going Ships Cleaner

With President Bush's July 21 signature on the Maritime Pollution Protection Act of 2008, U.S. agencies are setting course to implement a key international agreement to reduce air pollution from large ships.

This key step clears the way for U.S. ratification of the international treaty regulating emissions – known as MARPOL Annex VI -- from large diesel-powered, ocean-going vessels.

Under MARPOL Annex VI, container ships, tankers, cruise ships and bulk carriers must limit nitrogen oxide (NOx) emissions from their category three diesel engines. It also sets a cap on the sulfur content of the fuel they burn and includes a program for designating areas where more stringent fuel controls apply, such as near coastlines that have more severe air quality concerns.

This October, the parties to MARPOL will work to strengthen air emission standards and the sulfur requirements in fuel. The amendments under review are consistent with the stringent and comprehensive proposal put forward by the U.S. government. If adopted, these stronger international standards will yield significant environmental and public health benefits.

As foreign trade grows and EPA's new emissions controls take effect on other transportation sources, emissions from large ships comprise an increasing share of the nation's pollution inventory. In 2001, in terms of mobile sources, oceangoing vessels contributed nearly 6 percent of NOx, over 10 percent of particulate matter 2.5, and about 40 percent of SO2 to the nation's air pollution. Without further controls, those numbers will rise to about 34 percent of NOx, 45 percent of PM2.5, and 94 percent of SO2 emissions by 2030.

The final step of the ratification process is for the President deliver a letter -- known as diplomatic instrument of ratification -- to the International Maritime Organization. The U.S. becomes a party three months later. MARPOL Annex VI entered into force beginning in May of 2005, although ships have met most provisions since 2000.