(a) HHS, with the advice of the Advisory Board on Radiation and Worker Health, has issued regulatory guidelines at 42 CFR part 81 that OWCP uses to determine whether radiogenic cancers claimed under Parts B and E were at least as likely as not related to employment at a DOE facility, an atomic weapons employer facility, or a RECA section 5 facility. Persons should consult HHS's regulations for information regarding the factual evidence that will be considered by OWCP, in addition to the employee's final dose reconstruction report that will be provided to OWCP by NIOSH, in making this particular factual determination.

(b) HHS's regulations satisfy the legal requirements in section 7384n(c) of the Act, which also sets out OWCP's obligation to use them in its adjudication of claims for radiogenic cancer filed under Part B of the Act, and provide the factual basis for OWCP to determine if the “probability of causation” (PoC) that an employee's cancer was sustained in the performance of duty is 50% or greater (i.e., it is “at least as likely as not” causally related to employment), as required under section 7384n(b).

(c) OWCP also uses HHS's regulations when it makes the determination required by section 7385s-4(c)(1)(A) of the Act, since those regulations provide the factual basis for OWCP to determine if “it is at least as likely as not” that exposure to radiation at a DOE facility or RECA section 5 facility, as appropriate, was a significant factor in aggravating, contributing to, or causing the employee's radiogenic cancer claimed under Part E. For cancer claims under Part E, if the PoC is less than 50% and the claimant alleges that the employee was exposed to additional toxic substances, OWCP will determine if the claim is otherwise compensable pursuant to § 30.230(d) of this part.