US moves toward accord to reduce tanker emissions

May 13, 2002
The US EPA has requested public comment on a proposed rule governing air emissions from Category 3 marine diesel engines. Intertanko says that US acceptance of the standards, which generally conform to MARPOL Annex VI regulations, would likely influence worldwide acceptance of Annex VI .

By OGJ editors

HOUSTON, May 13 -- The US Environmental Protection Agency May 2 called for public comment on a proposed rule governing air emissions from Category 3 marine diesel engines that power much of the world's merchant fleet.

The 139-page document addresses a number of complex technical issues. While seeking comment on emissions standards for US flag vessels, it also conforms those standards to the limits on nitrogen oxides in Annex VI of the International Convention on the Prevention of Pollution from Ships (MARPOL)—with some notable exceptions.

"By announcing the intention of the United States government to seek Senate ratification of Annex VI, EPA has taken a major step [toward] preserving a US role in promoting global air quality improvements," said Peter Swift, managing director of the International Association of Independent Tanker Owners (Intertanko), Oslo, which has been pushing hard for uniform international standards as provided in MARPOL's Annex VI.

Many of the world's major maritime nations agreed to that treaty in 1997, but at least 15 nations that control over 50% of the world's shipping tonnage have not ratified it. Nonetheless, Swift said that US ratification would likely result in Annex VI's international approval "within the year."

The international shipping industry and its engine suppliers already comply, on a voluntary basis, with the Annex VI NOx requirements for new vessels. Intertanko's council has recommended that association members also adopt the association's VOCON operational procedure to reduce vapor emissions from tankers' cargo tanks during transportation. That policy, once implemented, also would contribute to global air quality improvement, Intertanko said.

Although United Nations data show that marine source air pollution represents only a small percent of overall air emissions—EPA notes that Category 3 marine diesels contribute only 1-2% of the total US NOx output —Intertanko's council stresses the need for international limits on ship emissions.

Certain other environmental organizations have not shared Intertanko's enthusiasm for Annex VI, arguing that its limits on NOx and sulfur oxides have been overtaken by new technologies. Swift counters that Annex VI would "no doubt" evolve over time to reflect technical progress in the control of marine air emissions.