PARKERSBURG — A commission overseeing pollution in the Ohio River may lessen standards that could threaten the water supply for millions of people, according to a coalition of environmental groups in opposition to the changes.

The Ohio River Valley Sanitation Commission is proposing revisions to its core mission that would eliminate key pollution control standards that are 60 years old and its responsibility to ensure consistent water quality throughout the Ohio River, the coalition said on Monday.

“ORSANCO commissioners walking away from their crucial oversight role will set the stage for a ‘race to the bottom’ in controlling pollution in the Ohio River,” said Madeline Fleisher, a senior attorney at the Environmental Law & Policy Center, one of the groups that submitted comments to the commission on the proposed change. “We can’t afford to lose the one watchdog in charge of making sure the entire Ohio River is safe and clean for more than 4 million people who rely on it for their drinking water.”

The commission, which took comments on proposed changes until Saturday, is considering five alternatives, but prefers No. 2, which, in light of the successes of the federal Clean Water Act and the related state water pollution control programs of member states, proposes its Pollution Control Standards be revised to recognize water quality standards and criteria are adequately addressed by member states in accordance with the federal Clean Water Act.

“The idea of ORSANCO abandoning their oversight of uniform pollution control standards flies in the face of why the Commission was established in the first place,” said Angie Rosser, executive director of the West Virginia Rivers Coalition. “This move would undermine the ability of the Ohio to recover as a healthy river system.”

The environmental groups submitting comments to ORSANCO were the Environmental Law & Policy Center, Ohio Environmental Council, National Wildlife Federation, Kentucky Waterways Alliance, Ohio River Foundation, West Virginia Rivers Coalition, Three Rivers Waterkeeper, Sierra Club, Hoosier Environmental Council and Ohio Valley Environmental Coalition.

“We still believe it is a very good idea for ORSANCO to ensure pollution dumped into the Ohio River doesn’t have a negative impact on waters of other states — especially in light of spills from recent times — like the MCHM spill in 2014,” said Robin Blakeman, project coordinator of the Ohio Valley Environmental Coalition. “Such petrochemical product spills are likely to be more, not less common in the future, especially if the massive Appalachian Petrochemical Storage Hub project becomes reality very close to the Ohio River.”