Mansfield Industrial, Inc. performs rust corrosion removal and prevention services on pipes at a Shin-Etsu Silicones of America, Inc. chemical plant in Freeport, Texas. In October 2016, two Mansfield employees were seriously injured when a pipe ruptured, releasing a hazardous chemical. Following an inspection, the Occupational Safety and Health Administration issued Mansfield a two-item serious citation. The first item, grouped for penalty purposes, alleges violations of the Process Safety Management (PSM) and Hazard Communication (HazCom) standards (Citation 1, Items 1a and 1b). The second item alleges a violation of a general industry personal protective equipment (PPE) standard (Citation 1, Item 2). Following a hearing, Administrative Law Judge Sharon D. Calhoun affirmed all three violations and assessed the proposed $23,350 penalty. For the reasons discussed below, we affirm Items 1a and 1b and vacate Item 2.