In October 2015, a Lane Construction Corporation employee was fatally injured while operating a diesel-powered hammer used to drive concrete support pillars (“piles”) at a bridge construction project in Ocoee, Florida. Following the accident, the Occupational Safety and Health Administration conducted an inspection of the worksite and issued Lane a single-item citation alleging a serious violation of the Occupational Safety and Health Act’s general duty clause, 29 U.S.C. § 654(a)(1), for exposing employees to “struck-by hazards” while they worked near the hammer’s base of operation. Following a hearing, Administrative Law Judge Heather A. Joys affirmed the violation as serious and assessed the proposed penalty of $6,300. For the following reasons, we reverse.