WASHINGTON — Environmental Protection Agency Administrator Scott Pruitt vowed Tuesday to cut through bureaucratic red-tape that has slowed the cleanup of toxic Superfund sites and follow a task force’s recommendations to act more boldly in holding companies responsible for past contamination.

Pruitt said the EPA is creating a “top 10 list” of key sites where nearby residents are in harm’s way so that the agency can aggressively address those locations. In recent memos to staff, he said that Superfund cleanup efforts would be “restored to their rightful place at the center of the agency’s core mission,” that his approach would target sites where decontamination is estimated to cost $50 million or more and that he would be personally involved in trying to fix the problem.

There are 1,300 Superfund sites nationwide, and more than 100 have languished for at least five years with no formal remedy plan. Pruitt declined Tuesday to say which sites might make the list of 10, but in a discussion with reporters at EPA headquarters, he repeatedly referred to a landfill with radioactive waste outside St. Louis and a public housing complex saturated with lead contamination in East Chicago, Indiana.