Chlorine and public health

Everything that is essential to our survival is also a potential vector of disease and sometimes death: what gives life also takes it away. The food we eat, the medicines we use, the air we breathe can all be dangerous to the health in excess - the dose is the poison.

Oxygen is a good example of this: massive doses of this precious gas are fatal, yet without it life would be impossible.

Chlorine makes a vital contribution to human health although some chlorinated derivatives are toxic in specific doses.

Chlorine has an established place in the natural world: the sea, plants and animals all contain and produce vast quantities of chlorinated molecules with sometimes quite extraordinary biological properties. In the human body itself, chlorinated compounds are indispensable to the functioning of the vital organs (for example, the role of hydrochloric acid in the digestive process).

In the case of drinking water, there is a close link between biological purity and preventative chlorination, which eliminates the risk of microbial infection. Louis Pasteur once said, '80% of diseases are in what we drink'; this is supported by the World Health Organization WHO who estimates that diseases associated with dirty water cause some 25,000 deaths per day.

Hygiene is another area where chlorine plays a part in the prevention of infection. The most obvious example is bleach, a powerful disinfectant used to combat microbial contamination and contagion, particularly in hospitals.

Chlorine plays an important part in the manufacture of medicines - 85% use chlorine chemistry, either in their final formulation or as part of the manufacturing process. Many medications administered for the treatment of hay fever, malaria, meningitis, typhoid fever, pneumonia and whooping cough, as well as certain tranquillizers, antiseptics, muscle relaxants, vitamins and products for the treatment of cancer - 20% of the most recently patented pharmaceutical products - contain chlorinated derivatives. Furthermore, hydrochloric acid is used to aid the adsorption of molecules that the body would not otherwise adsorb.

Chlorine is also widely used in research for the formulation of new active substances which, if successfully developed, could counter some of the great challenges facing modern medicine.

Chlorine makes other important contributions in the medical field: it is an essential material in the manufacture of medical accessories such as dialysis and transfusion equipment, blood bags, blister packs, catheters, surgical gloves, packaging used to preserve and protect medicines, prostheses, soft contact lenses and pacemakers.