More than a dozen people have suffered severe exposure to dangerous fumes after a chemical spill in Tamworth in Staffordshire.

Several are said to be in a serious condition in hospital following the leak.

The chemical concerned is titanium tetrachloride, an unstable compound which, on contact with water, is swiftly converted into hydrochloric acid.

It is used widely in industry, either to make titanium itself or to produce pigments used in paint.

If the liquid itself is spilled onto the skin, burns or severe irritation are likely to occur.

Splashes into the eyes can cause permanent damage to vision.

But a major spill, combined with moisture is in the air, means a large quantity of hydrochloric acid fumes.

If breathed in any great quantities, the acid can cause serious damage to the mucous membranes of the nose and throat, and particularly the lungs.

Fire burns

These will leave similar burns to those suffered by fire victims who have breathed hot gases.

The airways can become constricted due to tissue damage, making it hard to breathe.

If enough of the surface area of the inside of the lung has been damaged by the acid fumes, the patient could die.

The treatment doctors can offer is limited - oxygen to maximise the efficacy of lung tissue which is undamaged, and drugs to increase lung capacity.

It has been reported that victims of the Tamworth leak have had to be decontaminated before they can be moved to hospital.

Washing off remaining amounts of the acid from the skin not only minimises the potential burn, but reduces the risk to medical professionals who will be handling the patient later on.