Most commentators are obsessed with the radioactive effects of depleted uranium, ignoring its purely chemical properties. But missiles made from it break up, vaporise and/or ignite on impact, and are dispersed into the atmosphere, sometimes as an aerosol made up of the fine dust of the metal and its oxides. The particles then fall back to earth. If they become airborne again, they can be inhaled or ingested days, weeks, even months or years later. So you do not have to be inside or near a tank when it is hit to be at risk of absorbing these dangerous substances.

The 9th edition (1976) of the Merck Index (1), one of the world's bibles of chemistry, describes uranium and its salts as "extremely toxic", causing dermatitis, renal lesions, acute arterial necrosis, possibly resulting in death (2). Another such bible, the Handbook of Chemistry and Physics (3), describes it as "highly toxic, both from chemical and radiological standpoint". It gives the maximum concentration of its insoluble derivatives (oxides, for example) recommended as acceptable in air (based on its chemical toxicity) as 0.25 mg per cubic metre (4). The chapter on human exposure to airborne contaminants gives a figure of 0.20 mg (expressed as pure U) per cubic metre for natural uranium and its soluble and insoluble compounds. The comparable figures for lead arsenate are 0.15 mg or 0.20 mg, phosgene 0.40 mg and arsenic 0.50 mg. These figures were published in 1983 in the Encyclopaedia of Occupational Health and Safety (5), which puts the lethal dose for one half of experimental subjects (rats and rabbits) at between 0.55 mg and 1.12 mg per kg body weight. This is similar to the concentration (1 mg/kbw) of hydrogen cyanide (the Zyklon B used in Nazi extermination camps) needed to kill a human.

The same book describes at length the lesions characteristic of chronic poisoning by the metal and its oxides: pulmonary fibrosis and changes to the blood with a reduction in the number of red and white corpuscles (lymphocytes). The nervous system can also be affected. And there is the possibility of nephritis, chronic hepatitis, gastritis and other symptoms.

(2) The most recent edition (1996) merely states that uranium presents both a " toxic " and a radiological hazard and that direct contact with metallic U or its insoluble compounds may cause dermatitis. The word " extremely " and the references to renal lesions, arterial necrosis and death have been removed.

(3) Published by CRC Press, Boca Raton, Florida.

(4) Or, per kg, the theoretical contamination of around 2 sq km to a height slightly more than that of a man (2m).

(5) Published by the International Labour Office, Geneva.

Translated by Malcolm Greenwood