CINCINNATI (AP) — A commission that watches over the Ohio River’s health across six states is looking at making some of its pollution standards for the river voluntary.

The Ohio River Valley Water Sanitation Commission has been considering changes to the standards for more than a year.

Last year, it put off a vote to move away from its role of setting pollution standards for the river.

Several environmental groups say they’re worried that changes to the standards could weaken water quality protection for the river that provides drinking water for 5 million people.

But supporters of the changes say they wouldn’t affect water quality and point out that the federal Clean Water Act already sets standards for the river.