A participant of a multiemployer pension plan recently passed away. The participant's benefits were 100% vested. The participant, however, stopped working for a contributing contractor in 1979. Should the plan refer to the plan document that was in effect when the participant last worked (i.e., 1979) or the current document in determining whether the participant qualifies for a death benefit to be paid to his beneficiary?

Thanks!

Simple answer: BOTH

Second answer: and all amendments between 1979 and now.

The key issue on any intermediate amendments, such as REA, is that some provisions apply to all participants,
such as JS rules. Other provisions only apply if the document says so, and some amendments are only effective for those who work in active employment after the effective date.