Montville ― The U.S. Coast Guard, state environmental officials and an environmental cleanup company responded Wednesday afternoon to a 1,200-gallon diesel spill in the Thames River.

The spill occurred shortly after 1 p.m. during the refueling of the Atlantic Oceanic, an approximately 165-foot tug and supply ship, at Gateway Terminal, according to Paul Copleman, spokesman for the state Department of Energy and Environmental Protection.

An overflow of approximately 1,200 gallons of diesel spilled into the Thames River. A boom was in place around the vessel, a standard refueling precaution, at the time Copleman said. Most of the fuel was contained by the boom, but some fuel did escape into the river, he said.

Kropp Environmental Services responded. An additional containment boom was deployed and a vacuum truck on shore was working Wednesday afternoon to recover the fuel. Copleman said additional services responded to vacuum fuel from the water.

The Atlantic Oceanic is a US-based ship that was used earlier this year to aid in the installation of some of the 62 foundations for offshore wind turbines as part of Vineyard Wind. Vineyard Wind is an offshore wind farm being built 15 miles off the coast of Martha’s Vineyard by a joint venture between Avangrid and Copenhagen Infrastructure Partners.

In a statement released in June, Vineyard Wind said the Atlantic Oceanic and Northstar Navigator deployed bubble curtains designed to absorb and dampen sound during foundation installation.

Editor’s note: This story was updated to include more information about Atlantic Oceanic.