Requires employers with more than 20 employees to grant employees working 20 or more hours a week 3 hours leave of absence in any 12 month period to donate blood; provides such leave may not exceed 3 hours unless otherwise agreed to by the employer; provides that an employer shall not retaliate against an employee for requesting or obtaining such leave; these provisions shall not prevent an employer from providing leave for blood donation in addition to leave allowed under any other provision of law and shall not affect an employee's rights with respect to other benefits provided by law.