(1) In the case of a plan maintained on January 1, 1974, pursuant to one or more agreements which the Secretary finds to be collective bargaining agreements between employee organizations and one or more employers, no plan shall be treated as not meeting the requirements of
sections 1054 and
1055 of this title by reason of a supplementary or special plan provision (within the meaning of paragraph (2)) for any plan year before the year which begins after the earlier of—
(A) the date on which the last of such agreements relating to the plan terminates (determined without regard to any extension thereof agreed to after September 2, 1974), or
For purposes of subparagraph (A) and
section 1086(c) 1 of this title, any plan amendment made pursuant to a collective bargaining agreement relating to the plan which amends the plan solely to conform to any requirement contained in this chapter or title 26 shall not be treated as a termination of such collective bargaining agreement. This paragraph shall not apply unless the Secretary determines that the participation and vesting rules in effect on September 2, 1974, are not less favorable to participants, in the aggregate, than the rules provided under
sections 1052,
1053, and
1054 of this title.
(2) For purposes of paragraph (1), the term "supplementary or special plan provision" means any plan provision which—
(A) provides supplementary benefits, not in excess of one-third of the basic benefit, in the form of an annuity for the life of the participant, or
(B) provides that, under a contractual agreement based on medical evidence as to the effects of working in an adverse environment for an extended period of time, a participant having 25 years of service is to be treated as having 30 years of service.