Liquids and vapours
The most common risks to health in working life is caused by vapours and splashes from solvents. Solvents have the ability to dissolve other substances, particularly greases and fats and they can evaporate rapidly. When a solvent evaporates, the vapour becomes part of the air that we inhale. It then travels through the blood to the internal organs, e.g. the brain and liver. Because solvents can dissolve substances they can also affect mucous membranes and the skin. Some solvents can even be absorbed through the skin, though the majority are inhaled.
The greater a solventís ability to dissolve greases or fats, the greater the effect it will have on the central nervous system. Dizziness, headaches, tiredness, reduced comprehension and prolonged reaction times are some of the symptoms of short exposure to solvents. Although these effects may disappear quickly they increase the risk of accidents.
It has been known that solvents which are absorbed and stored in the body have the same effects as an anaesthetic, for a long time. In fact many solvents were previously used as anaesthetics, intoxicating people and putting them to sleep. In extreme cases the effect of the anaesthetic is loss of consciousness and death. Some of them have a very low viscosity, and the concentration in the work premises can easily rise to very high levels if the solvent is not handled properly. Vapours from solvents containing chlorine can produce phosgene and hydrogen chloride when they come into contact with hot objects.
Solvents can reach the brain both through the lungs and through the skin. The brainís cells contain a lot of fat and therefore attract fat-dissolving substances.
Acids and Alkalies
Acids and alkalis are corrosive substances which can damage the skin and eyes on contact. A corrosive mist can form above acids and damage the respiratory tract and lungs. Especially dangerous acids include hydrochloric, sulphuric, chromic and nitric acids. Among other things, alkaline substances are used to clean grease from metal objects. Caustic soda and ammonia are examples of alkalis. Contact with the skin can cause serious burns unless large amounts of water are used to rinse the substance off.