BEAUFORT — A company that knowingly hires illegal immigrants could lose its business license under a county law given final approval Wednesday evening.

Beaufort County Council unanimously approved the local law, dubbed the “Lawful Employment Ordinance,” 9-0, following a public hearing. It is set to take effect Jan. 1, 2008.

Under the ordinance, people who apply for a county business license must sign a form verifying, under penalty of perjury, they do not knowingly employ or plan to hire an illegal immigrant. Licensed companies would be subject to county audits of their employees’ documentation.

Details of the random audit process are yet to be worked out, but a council committee suggested annual audits for 25 percent of the roughly 5,000 businesses licensed with the county. That would cost an estimated $210,000 and require an additional six employees, said Beaufort County Administrator Gary Kubic.

The proposal had changed significantly since its introduction in September, and the council called a special meeting to vote on the issue before six new members are sworn in next week.

The proposal initially allowed complaints to drive investigations — a system opponents said was susceptible to abuse — and encouraged businesses to enroll in a free federal program to verify employees’ immigration statuses. Those were removed from the ordinance after council members received closed-door legal advice.

Hispanic and business groups, including construction firms, restaurants and hotels, had called the law unconstitutional and questioned how the ordinance would be enforced and its effects on the economy.

The revised ordinance passed 9-1 earlier this month, setting up Wednesday’s final vote.

“It still leaves major questions unanswered,” said Charlie Clark, spokeswoman for the Hilton Head Island-Bluffton Chamber of Commerce. Clark said it’s “going to be extremely difficult” for one community to resolve an issue being debated nationally.

Carlotta Ungaro, president of the Beaufort Regional Chamber of Commerce, calls the revised proposal unnecessary. She said business owners already sign statements saying they won’t hire illegal immigrants.

And many businesses operate in Beaufort County without a license, so the ordinance would unfairly burden owners “trying to do the right thing,” she said.

Kubic welcomed the chamber’s help in finding unlicensed businesses.

“Two wrongs don’t make a right,” he said.