Oregon's top labor official widened his agency's investigation into a Portland contractor who employed traffic flaggers on the Sellwood Bridge project.

In a complaint lodged last week, Commissioner Brad Avakian alleged Evan D. Williams threatened to physically harm his employees last fall in response to a state investigation into unfair pay. Williams is also accused of firing some whistleblowers in retaliation.

Avakian's action launches a civil-rights investigation into the firms that could take up to one year.

"It's critical that workers are able to file wage claims with our agency free from retaliation and harassment," Avakian said in a written statement issued Tuesday.

Messages left for Williams at two of his businesses have not been returned.

The Oregon Bureau of Labor and Industries has investigated allegations of wage violations against Williams' businesses since 2011.

Employees of one company, Tri-Star Flagging, turned to the agency en masse in June 2013. Investigators eventually found that 37 workers hadn't received fringe benefits owed for their work on the replacement for the Sellwood Bridge. The employees split $104,000 recovered by the state on their behalf.

Labor regulators also moved to ban Williams, 58, from public works projects and enforce a $94,000 penalty, but neither action has been finalized.

The agency has already imposed a three-year public contracting ban on Williams' companies and his wife Kenya Smith. She could not be reached by The Oregonian/OregonLive.

State business records link Williams and Smith to a handful of construction companies, most based in Oregon City or Portland. The firms include A D Traffic Control Services, Portland Flagging, Phoenix Construction Group, Tri-Star Flagging and SBG Construction Services. Only the latter two have active business licenses.

The Construction Contractors Board suspended Williams' license for failing to provide proof of insurance. However, he did secure a business loan that was registered in November with the state.

The new investigation into Williams and his firms could last up to one year, said Charlie Burr, a spokesman for the Bureau of Labor and Industries. He said it was the eighth time Avakian had filed a complaint during his seven years leading the agency.

Daimler Trucks North America agreed to pay $2.4 million in 2016 to settle a civil-rights complaint that arose from several allegations of discrimination.

If regulators find evidence to prove the allegations against Williams of retaliation, they will try to reach a settlement between both sides. If that doesn't resolve the matter, an administrative law judge would likely consider the case and weigh in on penalties. But the final decision would rest with the state's deputy labor commissioner, Burr said.

-- Molly Young

myoung@oregonian.com

503-412-7056

@mollykyoung