WASHINGTON — House Democratic leaders said on Wednesday that they would no longer dole out budget “earmarks” to profit-making companies, wiping out one of the most lucrative and controversial means of awarding no-bid contracts to private firms.

The ban is the most aggressive step yet in a three-year effort in Congress to curb abuses in the awarding of earmarks, which direct that federal money be spent in a very specific way. The move follows criminal investigations, ethics inquiries and political embarassment linked to the use of earmarks.

If the ban had been in effect last year, it would have blocked some 1,000 earmarks, many of them for military contractors that received multi-million-dollar contracts, leaders of the House Appropriations Committee said in announcing the decision.