BATH — A local environmentalist is saying possible contamination of the Kennebec River by Bath Iron Works could hinder progress in restoring the river’s water quality.

The shipyard has said it will pay $355,000 to the Environmental Protection Agency for alleged violations of the Clean Water Act for failing to comply with stormwater permit requirements and failing to submit Toxic Release Inventory reports for heavy metals and chemicals.

“The Kennebec has been a really good example of how a lower river can get restored,” said Ed Friedman, chairman of Friends of Merrymeeting Bay. “There are some really large migratory fish populations in the water now, as well as recreational users of the river.

“So when you start to put … toxics associated with painting or other shipbuilding uses like sandblasting into the river, you’re putting toxics into the river. That’s not a good thing. Some of those effects might not be as overt as, say, an oil spill. The effects are more subtle.”

Friedman said one Zumwalt-class destroyer built in Bath costs more than $4 billion. He said “fines are never enough for multinational firms like BIW.”

In a statement, General Dymanics-owned Bath Iron Works said it worked quickly to fix any issues after it was made aware of them.

“In response to a 2016 inspection by the Environmental Protection Agency (EPA), Bath Iron Works took prompt corrective action to achieve compliance with state and federal regulations and permits,” the company wrote.

“BIW worked with the EPA to understand the agency’s interpretation of certain technical, regulatory compliance requirements and, ultimately, to settle matters arising under the Clean Water Act and reporting deficiencies under the Emergency Planning and Community Right to Know Act. As a result of those discussions and BIW’s cooperation, EPA reduced the penalties assessed.

“BIW is committed to working with state and federal agencies and our employees to ensure that shipyard operations are consistent with the environmental standards for shipbuilding in the state of Maine.”

The EPA alleged BIW violated the Clean Waters Act by not properly cleaning up blast grit, a byproduct of sandblasting.

The federal agency also alleged the shipyard failed to properly cover stormwater catch basins when conducting activities that produce blast grit. The settlement was not clear on whether blast grit entered the Kennebec River.

The agency also said wastewater from pressure washing vehicles at the shipyard was allowed to enter a catch basin that discharges into the Kennebec River. The shipyard did not have a permit allowing such discharge, according to the EPA.

The settlement does not say how much of the unauthorized wastewater actually entered the Kennebec River due to the alleged violations.

The EPA also alleged the shipyard failed to file certain reports on its use of chromium, copper, manganese and nickel from 2013 to 2015. In a release about the settlement, the EPA noted that the reports were required under the Toxic Release Inventory program for the purpose of letting community members and public officials to know what chemicals are being used nearby and whether they’re being discharged into the environment.

It was unclear whether any blast grit or unauthorized wastewater entered the Kennebec River due to the alleged violations.

“As long as they’re complying with the permit, we’re pretty sure that the water quality is pretty good,” said Barry Mower of the Maine Department of Environmental Protection.

Several environmental groups, including the Natural Resource Council of Maine and the Kennebec Estuary Land Trust, declined to comment on the settlement.