This incident is a tad dated (2016) but it is a perfect example of how a contractor doing work “adjacent” to a covered process can impact that process. It is also a great opportunity to discuss how to establish the process “battery limits”. I like to call this my “force field” around my process – NOTHING gets through the force field that is not authorized. The biggest focus in this is of course contractors (case in point). This topic is where the phrase “in, on, and adjacent” comes from, as the threat does not have to be actually working on the process or even within the process, it can be adjacent to the process and still impact the process. In this case, it was an “aerial lift” and the base was outside of the process, but the contractor “boomed” out and made contact with a valve in an ammonia line, causing injury to himself.