Federal contractors must now use an electronic system to verify employees’ eligibility to work in the U.S. and these are also expected to become mandatory for private employers, said a Wall Street Journal report. Already, some states require companies operating within their borders to use it, regardless of whether the companies have government contracts. About 169,000 federal contractors and subcontractors, who employ roughly 3.8 million workers, will eventually be covered by the program – E-Verify – taking effect from today. U.S. District Court Judge Alexander Williams Jr. rejected an 11th-hour-effort late Friday by the U.S. Chamber of Commerce and other business groups to delay the mandate while a federal appeal is pending. Upset about the liability the mandate puts on employers, the groups suing argue it is illegal for the government to extend E-Verify to contractors through an executive order. The Chamber argues that given the state of the economy, this isn’t the time to add more costs to U.S. businesses. Under the mandate, a clause requiring contractors and sub-contractors to use the system will be written into every new or renewed government contract starting . It will also be written into every new work order issued under existing contracts, officials say. It will be up to government agencies that issue the contracts to enforce the mandate. The E-Verify system compares data entered by employers with records maintained in Social Security Administration and immigration databases.