An employee was injured while working from an aerial lift basket at Respondent’s worksite in Littleton, Colorado on July 2, 2018. As a result, OSHA conducted an investigation. During the worksite inspection, Compliance Safety and Health Officer (“CSHO”) learned that employees were climbing on, standing on, and working from the aerial lift basket guardrails to perform their work. Based on CSHO’s investigation and recommendation, Complainant issued a Citation and Notification of Penalty, alleging Respondent committed a single, serious violation of 29 C.F.R. § 1926.453(b)(2)(iv), and proposed a penalty of $5,543.