Acute exposures and effectsAcute exposures and effects describe medical conditions that happen right after the person is exposed to a chemical, biological or physical agent at work. Such as, exposures to infectious disease from getting bit or being struck by a needle.
Chronic exposures and effectsOccupational diseases in this category involve medical conditions that develop slowly over time from prolonged or chronic exposures in the workplace. The disease and symptoms often show up while the person is still working in the place where they had the exposure. Such as, conditions like dermatitis and some respiratory diseases can be caused by constantly being exposed to chemical or biological agents in the workplace.
Long latency illnessesIn long latency illnesses, sometimes the symptoms may not show up until many years after an individual was exposed to the disease-causing agent. Such as, mesothelioma, which is a cancer of the pleura or peritoneum that can develop from exposure to asbestos that occurred decades ago.  
Noise-induced hearing loss (NIHL)It is a permanent hearing loss, usually in both ears, resulting from inner ear damage due to prolonged, continuous or intermittent hazardous noise exposure.

There are many occupational diseases. They range from acute exposure with immediate health effects to chronic diseases that may manifest after the worker has left the workplace. For the purposes of the review, we used the following terms and definitions.