The most obvious application of a fume hood is fume control. By recirculating the air inside of the cabinet and forcing it through an activated carbon filter, fume hoods protect scientists and workers from harmful chemical vapors and prevent the release of pollutants into the environment. The specific composition of the filter can be adjusted for different contaminants. As a further protective measure, a downflow of air at the entrance of the cabinet is used to keep the contaminated air away from the user.
Fume hoods are also necessary for industrial processes that release significant amounts of fine dust, even if it is not toxic. Long-term exposure to dust, even if it is in small concentrations, can lead to silicosis (also known as potter's rot) as the lungs are unable to expel the tiny particles. Said particles are easily captured by the filters and air downflows used in fume hoods.
When working with radio-chemical materials, special measures are needed. To provide proper protection when working with radioisotopes, fume hoods are usually lined with stainless steel, preventing absorption and facilitating decontamination. They are also reinforced to support the weight of lead bricks or other shielding materials if necessary.
Closely related to fume hoods, biosafety cabinets provide containment in laboratories where infectious agents are in use. Class I biosafety cabinets use an inflow of air to prevent escape of the infectious agent, but do not prevent the entrance of eternal elements. For extremely infectious agents and for cases where preventing external contamination is essential, Class III cabinets where the sample is manipulated by means of attached rubber gloves can be used.
Fume hoods are often designed to protect the user and those in the surrounding area from accidental explosions. Five of the six sides of a fume hood are usually closed, and in the sixth, a window will protect the user's face while allowing a view of the experiment. While fume hoods will not protect the user from major conflagrations unless specifically designed for that purpose, most models will afford at least basic protection from flying glass shards and spillages of toxic or corrosive materials.