Elected officials gathered along the East Boston waterfront Friday to celebrate the 50th anniversary of the Clean Water Act, crediting the federal legislation with transforming Boston Harbor into one of the nation's cleanest. At the same time, they warned that the landmark law is under threat.

Congress passed the Clean Water Act in 1972 as an expansion of federal protections dating back to the 1940s, giving the Environmental Protection Agency the power to regulate the discharge of pollutants into the nation's waterways. But the U.S. Supreme Court is considering a case this term that could dramatically scale back which waterways the act protects.

The event at East Boston's Piers Park called attention to the harbor as one of the act's notable achievements.

"50 years ago, Boston Harbor was essentially a trash can," said Radhika Fox, whose official EPA title is assistant administrator for the Office of Water, but whom the elected officials all referred to as "the Queen of Water."

"We dumped waste, we dumped chemicals — all sorts of things — into the water," she said. "And it wasn't unusual to Boston Harbor. ... And so what happened 50 years ago is that the American people said, 'You know, enough is enough. We care about our waters. We care about our communities.' And they called on Congress to do something about it."

A decade later, the city of Boston was sued by the federal government, the Conservation Law Foundation and the city of Quincy under the Clean Water Act, compelling the city to upgrade its sewage treatment facilities. Today, the cleanup of Boston Harbor is widely considered to be a major environmental success.

Boston Haror
The view of Boston Harbor from Piers Park in East Boston
Craig LeMoult GBH News

On Monday, the Supreme Court heard oral arguments in a case challenging the scope of the act. The suit was filed against the EPA by an Idaho landowner, challenging whether the federal law has jurisdiction over wetlands.

Speaking at the East Boston event, Sen. Ed Markey said the court case is an "unprecedented attack." Markey has served 46 years on the Environment and Public Works Committee, which has jurisdiction over the Clean Water Act.

"This Supreme Court, after what it has just done on guns, on abortion, is poised to roll back the protections for the water in our country," the Democratic senator said. "So as much as we're celebrating today, we still have fights ahead of us."

In the first three decades after the Clean Water Act was passed, Boston Mayor Michelle Wu said, the number of rivers safe for fishing in the United States increased by more than 10%.

"This is proof that we're able to get real results, improve lives and realize the full potential of our green spaces when we work together," Wu said. "But ... I want to make sure that on this day we're not just celebrating what has been possible in the past as our history, but reaffirming our commitment to what lies ahead. There's still a lot that we need to take on."

Wu shared Markey's concerns over the impact of a possible Supreme Court ruling limiting the scope of the Clean Water Act.

"In a nation where we lose one and a half million acres of natural land to development each year, a ruling against the Clean Water Act would pave the way for a devastating acceleration of these losses," she said.

U.S. Rep. Ayanna Pressley called access to clean water a "fundamental human right."

"And as the congresswoman of the Massachusetts 7th [District], it is a source of pride for me that we have changed the legacy of this harbor, where it went from being one of the most polluted in our nation to now being amongst the cleanest," Pressley said. "And that is the type of role that I want this district to play in our commonwealth and in our country, that we are the pace setters, that we set the blueprint for what justice in every iteration looks like, including and especially when it comes to our environment."