"If you don’t use it for a year, toss it out." Forgotten items stored in closets, basements, attics can be easily recycled over time. But what if you don’t realize that a dormant system in the house itself hides a safety threat? Valero’s McKee Refinery Propane Deasphalting (PDA) Unit posed a hazard that no one saw coming. A control station in the PDA unit was shut down in 1992, and rather than remove or purge the idle subsection, the refinery simply closed the valves around the section and left it in place for 15 years. Cold February 2007 temperatures froze trapped water in the unused propane piping, cracking it. Leaking propane quickly ignited and set the refinery ablaze. Responders battled the intense fire but had to evacuate when flames engulfed local propane shut-off valves, defeating efforts to isolate the fire. Aging NASA facilities bear silent witness to past science and engineering achievements spanning two centuries; some infrastructure awaits renewal, some awaits demolition. Conversely, new designs for ambitious missions far from Earth must be able to withstand and adapt to unplanned events. In both cases, the capacity to detect and correct for emerging threats will spell the difference between loss or sustainment, failure or achievement. Read this month’s Case Study and consider latent sources of violent energy release, and our control over them.