Page header image of an ore ship on Lake Superior

Environment and Sustainability

Keeping our seaway healthy.

Key stakeholders on the Great Lakes-St. Lawrence Seaway System, including the Duluth Seaway Port Authority, formed Green Marine, a voluntary partnership, in 2009 to continually improve the maritime industry’s environmental performance. Green Marine’s ongoing efforts encourage and promote sustainable maritime development along this binational trade corridor and around the world. Partners adopt environmental best practices and evaluate their performance each year in a variety of categories including emissions, greenhouse gases, cargo residues and environmental leadership in an effort to reduce the industry’s collective environmental footprint.

Environmental FAQ

What is being done to control the entry of aquatic non-native species from ballast water into the Great Lakes?

The Great Lakes-St. Lawrence Seaway has the most stringent ballast water management and inspection measures in the world. A joint Canada-U.S. inspection program has been in place since 2006 that inspects all arriving vessels from overseas. Oceangoing vessels must exchange ballast and flush tanks before arriving in domestic waters. Since this program started, no new aquatic invasive species invasions due to shipping have been documented in the Great Lakes region.

Domestically, the Vessel Incidental Discharge Act (VIDA) became law in December 2018. VIDA requires the U.S. Environmental Protection Agency (EPA) to develop new national standards of performance for commercial vessel discharges and the U.S. Coast Guard to develop corresponding implementing regulations. Discharge standards are technology-based and in the form of numeric effluent limits and best management practices; distinguish among classes, types, and sizes of vessels, and between new and existing vessels. The unique bulk cargo vessels operating exclusively within the Great Lakes encounter particularly challenging conditions that prevent typical ballast treatment systems from providing consistently effective treatment. Therefore the EPA is supporting research and development of treatment technologies through the Great Waters Research Collaborative in Superior, WI. For more information on aquatic invasive species, visit the Minnesota Sea Grant website.

What is ballast?

When not fully loaded, cargo ships must take on water (ballast) to maintain stability. Once pumped onboard, ballast water is stored in large confined compartments (ballast tanks) built into the hull of a ship.

What is happening with vessel sulfur emissions and the Emissions Control Area (ECA)?

In 2009, the United States and Canada requested that the International Maritime Organization (IMO) approve an ECA for most waters inside the EEZ. The IMO approved the request and the EPA issued proposed rules prohibiting vessels from purchasing fuel with sulfur content higher than 0.5 percent beginning in 2012 and 0.1 percent beginning in 2015. In 2020, the IMO also set a 0.5 percent limit for ships operating outside designated ECAs.

Current sulfur levels for residual fuels burned in ships’ power plants is about 1.5 percent, compared to a worldwide level of as high as 4.5 percent. Shipping interests recognized a safety and competitive problem with these rules because the ultra-low sulfur fuels are considerably more expensive than the fuels currently burned by most ships (up to 100 percent higher cost).

The Great Lakes were included in the proposed rules, which meant that a ship traveling to Duluth from the North Atlantic will need to burn the ultra-low sulfur diesel fuel for about 2,500 miles both inbound and outbound from Duluth. There is much concern about the competitive implications of this, and many believe it could cause modal shifts away from efficient ships to much less efficient rail and truck shipments to the coasts, as this regulation could add up to $3 per ton to the cost of transporting a cargo out of the system.

For domestic ships, Congress acted to currently exempt the older steamers as well as certain older diesel-powered ships that cannot safely burn the low sulfur fuel or can demonstrate hardship due to new fuel regulations. Many ship owners and their trade and professional organizations are working to find ways to reduce their environmental footprint.