A/HRC/5/5 page 7 12. Voluntary or incidental oil spills and fires on land are common occurrences in armed conflicts. Although marine environments are particularly fragile, the effects of contamination by oil on land can also be significant and prolonged. Oil spills on land can be the result of a deliberate discharge, for example the filling of trenches with oil to slow down an advancing enemy force, or as a consequence of the destruction of oil wells. The destruction of oil stocks or refineries also has the effect of releasing oil and petroleum products in the vicinity of the targeted facilities. This can lead to the formation of oil lakes, as seen in the Kuwaiti desert in 1991. Hydrocarbons can by their nature be mobile in the ground, even more so when the soil is permeable, which often results in the contamination of groundwater and drinking water supplies.14 These oil spills also represent a risk to agriculture, especially if contaminated groundwater is used for irrigation purposes. 13. Oil fires, which are prevalent during armed conflicts, present an even more immediate health risk than leaking oil. In most cases they are the consequence of attacks on oil depots, refineries or petrochemical facilities. They can also be the result of the destruction of oil wells or the ignition of oil-filled trenches. Recent examples include the 600 oil wells that were set ablaze in Kuwait by Iraqi forces, the burning of millions of barrels of petroleum at targeted Iraqi refineries in 1991,15 and the burning of 80,000 tons of oil and oil products at the Pančevo refinery in Serbia following an air strike.16 Oil is particularly toxic when it burns in large quantities. Indeed, burning oil releases many noxious substances including sulphur dioxide, nitrogen dioxide, carbon monoxide, poly aromatic hydrocarbons, carbon soot and lead.17 Some of these substances can cause death upon exposure, namely through extreme heat and carbon monoxide poisoning. Furthermore, because of the smoke produced by the fires, the surrounding population can suffer immediate adverse health effects by inhaling toxic fumes. It is reported that hospital attendance records suggest that, following the burning of the Kuwaiti oil wells, there was an increase in upper respiratory tract and asthmatic symptoms.18 Longer-term adverse health effects are caused by pollutants that have chronic and sometimes carcinogenic effects, such as polyaromatic hydrocarbons and carbon soot. Finally, human health could also be affected by the consumption of contaminated agricultural products or water. Black rain, caused by the smoke of oil fires, can facilitate the penetration of pollutants in the ground and cause long-term damage to crops, soil and groundwater. 14. Widespread availability of chemicals as well as the targeting of industrial sites in modern warfare makes it more likely that chemicals will be released in the event of an armed conflict. 14 UNEP, Desk Study on the Environment in Iraq, (2003), p. 79. 15 Ibid., p. 65. 16 UNEP, The Kosovo Conflict - Consequences for the Environment and Human Settlements (1999), p. 31. 17 Ibid., p. 34. 18 UNEP, Desk Study on the Environment in Iraq (2003), p. 68.