This proceeding is before the Occupational Safety and Health Review Commission (the Commission) pursuant to § 10(c) of the Occupational Safety and Health Act of 1970, 29 U.S.C. § 659(c) (the Act). On July 13, 2020, OSHA’s Compliance Safety and Health Officer (CO) Michael Marquez and later in September 2020, CO Reginald Benson, inspected a residential construction worksite in Naples, Florida. (Tr. 34-35; Joint Preh’g Statement, ¶ D, 1, 4). BCB Homes (BCB) was the general contractor at the site. (Tr. 36-37; Ex. C-25). BCB hired Morca Construction Services, Inc. (Morca Construction) and Ott Welding. (Tr. 25-26, 36-37; Ex. C-25). Morca Construction was hired to pour and install concrete columns on the first floor, along with the tie beams to which hollow core slabs were to be attached. Morca Construction hired American Precast LLC (American Precast) (also known as Mellor & Sons, Inc. (Mellor & Sons)) to fabricate the hollow core slabs. (Tr. 26, 36-37; Ex. C-25). American Precast and Mellor & Sons fabricated the hollow core slabs offsite. (Tr. 26, 36-37). The owner of American Precast and Mellor & Sons, Victor Mellor, hired Revolution Erecting, LLC (Revolution or Respondent) to install the hollow core slabs. (Tr. 19-20, 36-37, 90-91, 332-34, 342; Ex. C-25). Ott Welding was hired to install steel ledger angles, which supported the hollow core slabs. (Tr. 37-38, 108, 195). American Structural Engineering (ASE) was the engineer of record. (Ex. C-37).