A person can hurt their back from lifting something too heavy. Someone can get frostbite from working outside in the winter. The type of harm that can occur depends on certain factors. The strength, or ability of an agent or process to cause serious problems. Hazards can affect health in different ways.
Some hazards affect workers right away or soon after they are exposed.
Symptoms that show up quickly are called acute effects . For example, exposure to chlorine makes it hard to breathe, and causes nausea, and stinging and burning sensations in the eyes, nose and throat. Many health problems are long lasting but do not show up right after an exposure. The symptoms or disease happen long after exposure or from being exposed to small amounts of an agent for a long time. These delayed or long lasting problems are called chronic effects.