29 U.S.C. § 2107: Authority to prescribe regulations

(a) The Secretary of Labor shall prescribe such regulations as may be necessary to carry out this chapter. Such regulations shall, at a minimum, include interpretative regulations describing the methods by which employers may provide for appropriate service of notice as required by this chapter. (b) The mailing of notice to an employee’s last known address or inclusion of notice in the employee’s paycheck will be considered acceptable methods for fulfillment of the employer’s obligation to give notice to each affected employee under this chapter.