Starting Sept. 8, federal contractors and subcontractors will be required to use a federal verification program to check whether their employees are eligible to legally work in the United States. The program, known as E-Verify or Basic Pilot, has been controversial because of errors in the databases that it relies on.

It’s a free, Internet-based system operated by the Department of Homeland Security in partnership with the Social Security Administration that uses information from the Employment Eligibility Verification Form (I-9). It’s meant to screen current employees, not potential hires. For the past five years, the program has been offered on a voluntary basis. Nationwide, about 144,000 companies at more than half a million worksites use E-Verify.

[1] http://www.oregonlive.com/business/index.ssf/2009/09/everify_becomes_mandatory_empl.html