Trustee decisions final & binding

[Guest sidalee1]

We have a situation wherein several years ago (5+) a participant requested and was denied disability benefits because she had not attained the requisite age at the time her employment terminated due to the disability. A union trustee now wants to reopen the issue claiming there are new facts - these facts were known at the original meetings, but the trustee is claiming she was unaware and/or misunderstood the information. Are there any cases out there or can somebody guide me to information which states that the decision back over 5 years ago is final and binding on the trustees and that the case cannot be reopened? If the trustees can in fact reopen cases such as this, what prevents them from reopening and rehearing almost any other case?

Any guidance is much appreciated!

Thanks and Happy Thanksgiving!