A plan fiduciary, employer, plan participant, or beneficiary, who is adversely affected by the act or omission of any party under this subtitle with respect to a multiemployer plan, or an employee organization which represents such a plan participant or beneficiary for purposes of collective bargaining, may bring an action for appropriate legal or equitable relief, or both.

Notwithstanding paragraph (1), this section does not authorize an action against the Secretary of the Treasury, the Secretary of Labor, or the corporation.

6 years after the date on which the cause of action arose, or

3 years after the earliest date on which the plaintiff acquired or should have acquired actual knowledge of the existence of such cause of action; except that in the case of fraud or concealment, such action may be brought not later than 6 years after the date of discovery of the existence of such cause of action.