On January 18, 2023, the Wilkes Barre, Pennsylvania, Area Office of the Occupational Safety and Health Administration (OSHA) conducted an inspection of Respondent Planet Fitness’s worksite gym, located at 21 Gateway Shopping Center, Edwardsville, Pennsylvania 18704 (Edwardsville’s worksite gym or club). On February 24, 2023, OSHA issued to Respondent, a four-item serious citation, with subparts, and a notification of penalty (citation). (GX-1, JX-1, Stip. 1). The OSHA Area Office sent the citation to Respondent’s Edwardsville worksite gym, by U.S. Postal Service, certified mail, return receipt requested. (JX-1, Stip. 2). The citation was delivered to the Edwardsville worksite gym on February 28, 2023, and the certified mail return receipt (green card) was signed and dated by Respondent front desk associate Grenwis Rivas. (GX-2; JX-1, Stip. 3). Therefore, the 15-working day notice of contest filing period ended on March 21, 2023.