Two participant-plaintiffs in a multiemployer pension plan each received a notice from the plan administrator that it was rescinding certain benefits and requesting approximately $40,000 in repayments. In granting defendant?ÃÃs motion to dismiss the plaintiffs'?Ã¡ equitable estoppel claim, the federal district court held that equitable estoppel may be a viable theory in ERISA cases involving welfare plans, but is not a viable theory for cases regarding ERISA pension benefit plans, especially in the absence of evidence of ambiguity in the plan provisions. Crawford v. PIUMPF, No. 3:10-00628 (M.D.Tenn. May 23, 2011).