47 CFR §1.1952

1. (a)When attempting to locate a debtor in order to collect or compromise a debt under this subpart or other authority, the Commission may send a request to the Secretary of the Treasury (or designee) to obtain a debtor's mailing address from the records of the Internal Revenue Service.
2. (b)The Commission is authorized to use mailing addresses obtained under paragraph (a) of this section to enforce collection of a delinquent debt and may disclose such mailing addresses to other agencies and to collection agencies for collection purposes.