Greenbrier Central LLC manufactures tank railcars at a facility in Marmaduke, Arkansas. On January 22 and 23, 2020, the United States Department of Labor, through its Occupational Safety and Health Administration (OSHA), conducted an inspection of the facility in response to a report of an injury sustained by an employee who required hospitalization. Two OSHA compliance safety and health officers (CSHOs) conducted the inspection and found no violation of the Occupational Safety and Health Act of 1970, (the Act), 29 U.S.C. §§ 651-78, related to the reported injury. One of the CSHOs, however, observed Greenbrier employees working near openings atop railcars without the use of fall protection. It was his opinion that the employees were exposed to fall hazards greater than four feet from the tops of the railcars to the lower levels of the railcars’ interiors. On July 22, 2020, OSHA’s Little Rock, Arkansas, Area Director issued a one-item Citation and Notification of Penalty to Greenbrier, which alleged Greenbrier violated 29 C.F.R. § 1910.28(b)(3)(i), by failing to ensure its employees were “protected from falling through any hole . . . that was 4 feet (1.2 m) or more above a lower level by” fall protection. The Secretary proposed a penalty of $10,603 for the Citation. Greenbrier timely contested the Citation, and the case was designated for Simplified Proceedings by the Chief Judge where the complaint and answer requirements were suspended.