Updated

The Port of Seattle's chief executive has resigned amid an investigation that determined the port had illegally given more than 600 workers about $4.7 million in extra pay.

The payments were discovered during a routine annual audit, which preliminarily determined that they were an unlawful gift of public money under the state Constitution, Kathleen Cooper, a spokeswoman for the Washington State Auditor's Office, said Friday. The payments were first reported by the Puget Sound Business Journal.

Ted Fick, who had been placed on administrative leave last week pending a review of his performance, resigned Thursday, less than three years after he was hired to the $350,000-a-year position. Neither his letter of resignation nor a letter from Tom Albro, president of the port commission, accepting the resignation referenced the auditor's findings.

"Over the past several months, I have come to the realization that my talents and strengths are better suited to the private sector, where I plan to return," Fick wrote.

Full audit results won't be released until the port has a chance to respond, Cooper said. The payments were made to 642 non-union, salaried employees, she said.

The port did not immediately have a comment Friday, but said it expected to provide further information later in the afternoon, spokesman Peter McGraw said.

It wasn't clear that the audit results prompted Fick's resignation. Fick had also been facing a charge of driving under the influence after a Washington State Patrol trooper clocked him at 79 mph in a 50-mph zone on the Highway 520 bridge across Lake Washington last April.

The arresting officer asked if he'd been drinking, and Fick responded that he was CEO of the port, according to an arrest report cited by The Seattle Times. His blood-alcohol content registered at 0.096, above the legal limit of 0.08.

The port operates Seattle-Tacoma International Airport, two cruise ship terminals and Fishermen's Terminal, home of the North Pacific fishing fleet, among other shipping terminals and marinas.

Chief Operating Officer Dave Soike, a 35-year veteran of the port, is serving as interim CEO.