This document discusses heat stress in the workplace. It defines heat stress and heat strain, and lists the four main environmental factors - temperature, humidity, radiant heat, and air velocity. It describes causal factors like age, fitness level, and acclimatization. Heat disorders include heat rash, heat cramps, heat exhaustion, and the most severe, heat stroke. Prevention methods include engineering controls, personal protective equipment, work practice controls, acclimatization, administrative controls, work monitoring, and training. The goal is to recognize heat hazards and prevent serious physical harm or death through these various controls and protocols.