29 U.S.C. § 1390: Nonapplicability of withdrawal liability for certain temporary contribution obligation periods; exception

first had an obligation to contribute to the plan after September 26, 1980 , 6 consecutive plan years preceding the date on which the employer withdraws, or the number of years required for vesting under the plan, was required to make contributions to the plan for each such plan year in an amount equal to less than 2 percent of the sum of all employer contributions made to the plan for each such year, and has never avoided withdrawal liability because of the application of this section with respect to the plan. the plan is amended to provide that subsection (a) applies; the plan provides, or is amended to provide, that the reduction under section 411(a)(3)(E) of title 26 applies with respect to the employees of the employer; and the ratio of the assets of the plan for the plan year preceding the first plan year for which the employer was required to contribute to the plan to the benefit payments made during that plan year was at least 8 to 1.