A federal court has blocked the implementation of the Department of Homeland Security’s Final Rule concerning Safe-Harbor Procedures for Employers Who Receive a No-Match Letter. The Final Rule—issued on August 15, 2007, and intended to take effect on September 14, 2007— provided that an employer’s receipt of a no-match letter from the Social Security Administration furnishes constructive knowledge that an employee lacks work authorization, but it also laid out a “safe-harbor” procedure for an employer to avoid liability. The federal court issued a preliminary injunction on October 10, 2007, against implementation of key provisions of the Final Rule on the grounds that the use of the error-prone Social Security records would result in discrimination against lawful employees and unduly burden small business owners.