LEWISTON — Environmentalists plan to celebrate the 45th anniversary of the Clean Water Act with a news conference Tuesday on the banks of the Androscoggin River.

The law, pushed by former U.S. Sen. Edmund Muskie of Maine, was inspired in part by the staggering amount of pollution in the river.

The Natural Resources Council of Maine is bringing some experts to the 11 a.m. event at Heritage Park in Lewiston. They plan to discuss what the river was like and how the law has helped revive it.

Among those slated to talk are Lynne Lewis, a Bates College professor; Dick Anderson, a fisheries biologist who found in the 1960s that no game fish existed in a long stretch of the river; and Natalie Lounsbury of River Rise Farm in Turner.

Organizers said they’ll talk about what’s happened during the past 45 years and what threats exist from environmental rollbacks by President Donald Trump. They’ll also talk about the role of Mainers in establishing the Clean Water Act, which took effect Oct. 18, 1972.

Sen. Edmund S. Muskie, D-Maine, on Oct. 5, 1970, before his speech to the Water Pollution Control Federation in Boston at a news conference. Muskie, who was chairman of the Senate subcommittee on air and water pollution, introduced amendments to the Federal Water Pollution Control Act.