Updated 1:15 p.m.

Senate Democrats blocked a major energy policy bill Thursday after failing to convince Republicans to attach an aid package addressing the drinking-water crisis in Flint, Mich. It is the latest sign that the public health disaster there has moved to the center of the national Democratic agenda.

Michigan’s Democratic senators, Debbie Stabenow and Gary Peters, proposed last week that Congress authorize up to $600 million in emergency aid to Flint. Most of that would be used to replace lead pipes that corroded because of a state-level decision to switch water sources; the rest would fund a center to monitor and treat the health of victims of lead poisoning.

In a tentative deal with the sponsor of the energy bill, Sen. Lisa Murkowski (R-Alaska), the Democrats agreed to modify their proposal to address concerns about the cost and structure of the aid. But Republican senators remained split on the deal, with some arguing that the package represents an unfair “earmark” for one city and could create a precedent for federal aid for other incidents that they see as a largely state and local responsibility.

“Given the fact that we have about $19 trillion in debt, I think it’s fair to ask, do we want to have the federal government replacing all the infrastructure put in place by cities and states all across the country?” Sen. John Cornyn (R-Tex.), the No. 2 Republican leader, said last week.

The pending energy bill if enacted would be the first major energy policy bill in nearly a decade. It includes a variety of measures aimed at modernizing the U.S. power grid, updating rules governing the transport of oil and gas, and encouraging renewable energy development, and it has enjoyed bipartisan support as it has moved onto the Senate floor.

But Democrats vowed to block the bill in a Thursday morning procedural vote if Republicans did not come to terms on Flint. The key votes failed 46 to 50, with 60 votes necessary to close debate and move to final passage of the energy bill.

Senate Minority Leader Harry M. Reid (D-Nev.) in a Thursday morning floor speech pointed to examples where Republicans had supported disaster aid for their own constituencies — including when Cornyn pushed for federal aid after a 2013 explosion at a Texas fertilizer plant that killed 15 people.

“I invite my Republican colleagues to come to the floor and explain to the country why this man-made disaster is not worth the attention of the Republican Party,” he said. “Why do Texans deserve federal assistance, but not the people of Flint?”

In floor comments of his own Thursday, Senate Majority Leader Mitch McConnell (R-Ky.) did not directly address the Flint controversy. But he said he did not want to see politics derail a large, bipartisan policy bill.

“There’s a lot for both parties to like in this bill,” he said. “Let’s not risk that progress.”

Stabenow rose to reply: “We’re just not done yet.” She later said that work toward a compromise would continue through the weekend.