JANE B. STRANCH, Circuit Judge. This petition concerns Arch Resources and Apogee Coal Company’s challenge of Black Lung Benefits Act (BLBA) liability for a claim submitted by David Howard. Howard mined from 1978 to 1997, and his last employer was Apogee Coal (at that time, owned and self-insured by Arch). The parties, referred to collectively as “Arch,” do not contest Howard’s entitlement to benefits for legal pneumoconiosis, but do dispute being identified as the liable insurer on Howard’s claim. Petitioners ask this court to review the Benefits Review Board’s decision affirming the Administrative Law Judge’s finding that Arch was the liable insurer for Howard’s benefits claim under the BLBA. Arch likewise asks this court to grant its motion to supplement the administrative record on appeal. For the reasons stated below, we DENY the petition for review and Arch’s motion.