This document discusses the importance of isolating hazardous energy sources before maintenance or repair work. It identifies several types of hazardous energy, including electrical, mechanical, chemical, thermal radiation, and pressure. Proper isolation is required when servicing equipment where parts could create a hazard, working on pipelines carrying hazardous chemicals, or working on electrical circuits with a risk of shock. Failure to isolate energy sources could result in injuries like electrocution, crushing, burns, or even death. The document stresses switching off and isolating all energy sources, as well as controlling stored energy through actions like blocking moving parts, before starting any maintenance work.