Federal officials are planning to launch another round of worksite investigations, focusing their attention this time on employers who have already been the subjects of Form I-9 inspections in the past three years.

Special agents will revisit about 500 employers to confirm any previous violations of immigration laws have been fixed, according to U.S. Immigration and Customs Enforcement (ICE). If employers have not implemented remedies to previous violations, they may face treble damages.

Under the Obama administration, ICE began conducting silent raids, which have resulted in the termination of large numbers of employees at some companies, rather than the Bush administration’s strategy of high-profile raids and mass arrests of undocumented workers. The agency also recently began conducting audits of small businesses.

But companies don’t need to run afoul of the law to get a visit from ICE. “The Obama Administration has re-imposed civil fines for paperwork and substantive violations, making Form I-9 errors an expensive problem,” Jackson Lewis noted in its legal alert on the issue. The law firm also advises that an employer consider compliance planning before it receives an NOI from ICE. (NOIs warn companies that they have three days to present Forms I-9 for all their employees for inspection.)

“Regardless of the size of a company, receipt of a NOI should be taken seriously, particularly if the employer has been targeted before. Receipt of a notice should trigger consultation with a designated team of experienced compliance experts for guidance through the ICE inspection process,” Jackson Lewis said in its alert.

Read more about firm’s advice for handling ICE investigations.