IMO rules to cut emissions from oceangoing vessels

New standards adopted by the International Maritime Organization (IMO) will require oceangoing vessels (OGVs) to reduce noxious emissions by at least 15 percent starting in 2011, with stricter limits for ships operating in designated areas already experiencing air-quality problems.

The guidelines, adopted Oct. 9, 2008, by the 168 Member States of the IMO, are contained in amendments to Annex VI to the International Convention for the Prevention of Pollution from Ships, also known as MARPOL. The amendments dovetail a proposal submitted to the IMO by the U.S. Environmental Protection Agency (EPA) in 2007.

In addition to tightening emission and fuel-quality standards on the open sea, the amendments allow the IMO to designate Emission Control Areas (ECAs) where stricter guidelines will apply regarding the discharge of sulfur oxides (SOx), nitrogen oxides (NOx) and particulate matter. To obtain ECA status, countries must petition the IMO. The EPA is working with the U.S. Coast Guard, State Department and other federal agencies to prepare an application to acquire the designation for America’s coasts.

“In today’s global economy, the number of ships doing business at U.S. ports is increasing at a rapid rate," the EPA stated in October. “Very few of these ships are U.S.-flagged, and the fuel they burn when entering U.S. waters has typically been obtained elsewhere, at ports all over the world. This new IMO program directly addresses emissions from these foreign-flagged vessels. It requires them to meet stringent standards whenever they operate in designated ECAs."

For vessels flagged and registered in the United States, EPA standards will continue to apply for engines with a displacement of less than 30 liters per cylinder (Category 1 and Category 2 engines). For engines with a displacement equal to or greater than 30 liters per cylinder (Category 3), the new IMO standards will apply.

The main propulsion for most oceangoing vessels, or OGVs — containerships, oil tankers, bulk carriers and cruise ships — is provided by Category 3 engines that are subject to Tier 1 emission standards. The standards were adopted by the EPA in 2003 and are equivalent to IMO limits. Tier 1 is the lowest level on a scale extending to Tier 3 to govern pollutants.

Under the new IMO guidelines, new Category 3 engines will have to meet Tier 2 standards in January 2011, resulting in a 20 percent reduction in NOx, according to the EPA. Engines installed before 2000, which currently are not subject to Tier 1 standards, must meet that requirement starting in 2011. The provision, expected to reduce NOx by 15 percent to 20 percent from current uncontrolled levels, is subject to the availability of certified engine-upgrade kits. In ECAs, new engines will have to meet Tier 3 standards starting in January 2016, resulting in an 80 percent reduction in NOx.

For fuel, the global cap for sulfur content will be 30,000 parts per million (ppm) starting in January 2012, with a 5,000 ppm standard going into effect in January 2020. For ships operating in ECAs, the standard will be 10,000 ppm in July 2010 and 1,000 ppm beginning in January 2015 — a 98 percent reduction from current levels.

“Considering the large contribution OGVs make to U.S. air quality problems, especially in port cities, the health benefits from these emission reductions will be very substantial," the EPA said. “We anticipate many billions of dollars of health and welfare benefits…if an ECA designation is made for U.S. coastlines."

The Coast Guard and EPA both have enforcement authority for Annex VI provisions, although the Coast Guard typically takes the lead regarding vessel inspections and compliance actions. Upon passing inspection, ships are issued a certificate valid for up to five years. Under the IMO’s NOx Technical Code, the ship operator is responsible for in-use compliance, not the engine manufacturer.

For more information on the IMO amendments, go to

Rich Miller

By Professional Mariner Staff