The U.S. Coast Guard will assist in the cleanup of an oil spill at Mill River in New Haven this week after a report filed by the Connecticut Department of Energy and Environmental Protection alerted them to the slick.

Coast Guard public affairs officer Martin Betts said that Coast Guard Sector Long Island first initiated a response on Sept. 15, which included a preliminary assessment of the nearby former English Station power plant facility. An analysis of the facility, the apparent source of the leak, proved that the site posed a substantial threat to the surrounding environment.

“Part of our mission is marine environmental protection, which involves dealing with oil and hazmat from a remediation standpoint,” Betts said. “The other thing is this is a waterside facility, so based on our mission, we’re beholden to act.”

According to DEEP spokesman Dennis Schain, because the contamination site is in the middle of an urban area, there is pressure to eliminate environmental and public health risks, as well as to determine if the facility can be placed back into productive use.

Schain said the site’s soil contamination required the DEEP to issue an earlier cleanup order that was contested by the facility’s owners at the time. Schain added that, due to related litigation, that order is still awaiting a decision from a superior court judge.

In the meantime, Schain said, DEEP’s emergency responders acted upon a report of an oil sheen near a catch basin adjacent to the English Station site. He said the report was filed out of concern that the oil would reach federal waters.

An incident news report from the Emergency Response Division of the National Oceanic and Atmospheric Administration’s website stated that the Coast Guard contacted the NOAA on Sept. 29 on the possible release of oil and other hazardous substances, and that the sector had requested NOAA aid in the identification of at-risk resources. The cause of incident was listed as discharge/dumping, and 6,000 gallons of various oils were at risk of spill.

Betts said that the Coast Guard, the lead federal agency in the cleanup response, has deployed booms to contain any hazardous material that could enter the marine environment. The effort is still in an assessment phase.

Margaret Miner, executive director of the Rivers Alliance of Connecticut, said that though the spill appeared relatively small, environmentalists have raised concerns regarding pollutants in and around the English Station facility.

Additionally, Miner said the spill is still concerning in its effects to the aquatic ecosystem — from fish to insects to birds — as Mill River is one of three important rivers that flow into New Haven.

“The Mill River and New Haven Harbor are certainly areas in which many people are working to restore the natural resources and aquatic life to the natural habitat, so any contamination is regrettable,” she said.

However, professor of environmental chemistry and environmental engineering Gaboury Benoit said that, although the situation was unfortunate, he did not think it was a serious problem that ordinary petroleum was the main contaminant in the spill.

“Oil spills [are] very spectacular and visible so people tend to respond to them,” Benoit said. “If this is limited to the quantity of oil — something that can be stored in a few barrels — then I don’t think this is very worrisome.”

Environmental Justice at Yale leader Sarah Lupberger FES ’15 said that she was aware of previous successful efforts by local environmental organizations to prevent English Station from reopening a few years ago. Lupberger also said that pollution from plants like English Station would have a greater effect on poorer neighborhoods, as these communities are less capable of objecting to the use of nearby land for purposes such as that of power plant facilities.

The English Station facility is currently owned by Asnat Realty LLC and Evergreen Power LLC.