This document discusses the importance of layers of protection in process safety. It provides an example where multiple layers of protection failed, resulting in a ruptured tank. Specifically, it summarizes that layers of protection include monitoring, procedures, alarms, interlocks, pressure equipment, and relief valves. It recommends never assuming alarms are faulty, understanding alarm status, properly maintaining relief valves, managing vent line pluggage, and being especially careful during non-routine operations when protections may be weaker.