Prosector
Generally, the risks to prosectors are low. Cadavers used for teaching purposes are embalmed before they are encountered by a prosector and students. Embalming fluid usually contains formaldehyde, phenol, Dettol, and glycerine which disinfect and kill pathogens within the cadaver. With exposure to embalming fluid, tissues and bodily fluids, such as blood, become fixed. Prosectors and students working with embalmed cadavers must always wear protective gloves, however this is more for protection against the harsh chemicals used in embalming such as formaldehyde and dettol which can cause moderate to severe skin irritation.
Hair coloring
The preparation (dye precursors) is in the leuco (colorless) form. Oxidizing agents are usually hydrogen peroxide, and the alkaline environment is usually provided by ammonia. The combination of hydrogen peroxide and ammonia causes the natural hair to be lightened, providing a "blank canvas" for the dye. Ammonia opens the hair shaft pores so that the dye can actually diffuse inside the fiber. These dye intermediates and coupler compounds can undergo oxidation and coupling reaction as shown in the scheme below to form high molecular weight products, which are trapped in the hair matrix and cannot be readily removed through washing.