If you maintain a practice that appears to be neutral, but creates an adverse impact on protected classes, you must prove that there is an overriding legitimate business purpose.
You must show that the practice is necessary to the safe and efficient operation of the business. You must also prove that the challenged practice effectively fulfills the business purpose it is designed to serve. A practice may not be permissible if an alternative practice would accomplish the business purpose equally well with a less discriminatory impact.1
1. Griggs v. Duke Power Company, 401 U.S. 424 (1971) ; 2 CCR sec. 11010