WASHINGTON — Senate Democrats blocked a comprehensive energy bill Thursday after Republicans balked over hundreds of millions of dollars in emergency federal aid to Flint, Mich., to fix and replace the city’s lead-contaminated pipes.

Minority leader Harry Reid said ‘‘100,000 people in Flint, Michigan, have been poisoned, and Republicans do nothing’’ to help them. ‘‘Nine thousand little children . . . have been poisoned. Still, Senate Republicans refuse to help.’’

The vote was 46-50, short of a number necessary to move ahead on the bipartisan legislation.

Democrats proposed a $600 million aid package for Flint last week, but Senator Debbie Stabenow of Michigan said they agreed this week to cut that proposal in half.

Senator John Cornyn of Texas, the second-ranking Republican, said it was premature to provide funds for Flint when state officials have not fully assessed their needs.

‘‘The fact of the matter is, the state of Michigan and the city of Flint don’t yet know what they need to do to fix the problem or how much it will cost,’’ Cornyn said.