26 U.S.C. § 4962

1. (a)If it is established to the satisfaction of the Secretary that—then any qualified first tier tax imposed with respect to such event (including interest) shall not be assessed and, if assessed, the assessment shall be abated and, if collected, shall be credited or refunded as an overpayment.
   1. (1)a taxable event was due to reasonable cause and not to willful neglect, and
   2. (2)such event was corrected within the correction period for such event,
2. (b)For purposes of this section, the term “qualified first tier tax” means any first tier tax imposed by subchapter A, C, D, or G of this chapter, except that such term shall not include the tax imposed by section 4941(a) (relating to initial tax on self-dealing).
3. (c)In the case of the tax imposed by section 4955(a), subsection (a)(1) shall be applied by substituting “not willful and flagrant” for “due to reasonable cause and not to willful neglect”.