29 U.S.C. § 1133 : US Code - Section 1133: Claims procedure

      In accordance with regulations of the Secretary, every employee
    benefit plan shall - 
        (1) provide adequate notice in writing to any participant or
      beneficiary whose claim for benefits under the plan has been
      denied, setting forth the specific reasons for such denial,
      written in a manner calculated to be understood by the
      participant, and
        (2) afford a reasonable opportunity to any participant whose
      claim for benefits has been denied for a full and fair review by
      the appropriate named fiduciary of the decision denying the
      claim.