ST. HELENS (AP) — Voters in Columbia County gave strong approval to a ballot measure that cracks down on employers caught hiring illegal immigrants.

According to the measure, the Columbia County Board of Commissioners must fine an employer that hires illegal immigrants $10,000 for a first violation. For a second violation, the board must seek to revoke the employer’s business licenses and permits.

Wayne Mayo, a contractor, was responsible for getting the item on the ballot in the county northwest of Portland. “This is about what’s legal and not legal,” he told The Oregonian newspaper. “It’s not fair that some contractors make money on the back of slave labor, when other contractors can’t compete with them.”

The Columbia County law has a few other aspects. The county has to contact local police and federal immigration officials about suspected illegal workers. It also must maintain a database of violations and require all county employers to use E-Verify, a free federal program that checks employment eligibility.

Similar laws have been passed in other places, such as Hazleton, Pa., and then challenged in court. Dave Fidanque, executive director of Oregon American Civil Liberties Union, said the ACLU is reviewing whether to challenge the law approved Tuesday by 57 percent of Columbia County voters.

“There’s a lot of frustration on the part of all Americans in terms of how our immigration laws have been enforced,” he said. “But having local governments stepping in and carrying out what is a federal obligation is not the answer.”

Sarah Hanson, the county’s legal counsel, said the measure has several flaws and is unlikely to survive a legal challenge in its present form. The measure, for example, suggests the county must revoke professional licenses, which the county has no authority to do.

The county is preparing an ordinance to fix some of the errors, then a judge will determine its validity, Hanson said.