Wanted: New chief executive to clean up radioactive mess. Hazmat suit not provided.

Wells Fargo is searching for a new leader after its chief executive, Timothy J. Sloan, abruptly resigned on Thursday, having been hounded by politicians, regulators, customers and employees about the halting efforts to overhaul the scandal-tarred bank.

Wells Fargo, the country’s fourth-largest bank, is starting its chief executive search from scratch. The chairwoman, Betsy Duke, said on Thursday that the board would try to recruit an executive from outside, someone without the baggage of being a Wells Fargo veteran.

Identifying a qualified candidate — a person with extensive banking and management experience, the credibility to pacify regulators and the skill to shepherd a company with 260,000 restive employees — will be a challenge. Persuading that person to take the job is likely to be even harder.

While Wells Fargo’s finances are fundamentally sound, the bank faces a daunting list of problems: litigation, with hundreds of millions of dollars on the line; more than a dozen restrictions imposed by federal regulators; a largely demoralized work force that is chafing under the bank’s leadership; and rigorous scrutiny of the bank’s next leader from high-profile members of Congress.