A/HRC/18/31 equipment in uncontrolled sites where it is easily accessible to the public, expose healthcare workers and the community to the risk of needle-stick injuries. Children are particularly at risk, since they can be hurt while playing with used needles and syringes. 28. Unsafe injection practices are a powerful means of transmitting blood-borne pathogens, including hepatitis B virus, hepatitis C virus and HIV. These viruses cause chronic infections that can lead to disease, disability and death a number of years after the injection. Epidemiological studies indicate that a person who experiences a needle-stick injury from a needle used on an infected source patient has risks of 30 per cent, 1.8 per cent and 0.3 per cent of becoming infected with hepatitis B, hepatitis C and HIV respectively.12 In 2000, WHO estimated that injections with contaminated syringes caused 21 million cases of hepatitis B infection (32 per cent of all new infections), 2 million cases of hepatitis C infection (40 per cent of all new infections) and 260,000 cases of HIV infection (5 per cent of all new infections).13 3. Chemical and pharmaceutical waste 29. Many chemicals and pharmaceuticals used in health-care establishments are hazardous. Some chemicals may cause injuries, including burns. Injuries can be caused when the skin, the eyes or the mucous membrane of the lung come into contact with flammable, corrosive or reactive chemicals (such as formaldehyde or other volatile chemicals). Other chemical and pharmaceutical products may have toxic effects through either acute or chronic exposure. Intoxication can result from absorption of the products through the skin or the mucous membranes, or from inhalation or ingestion. 30. Disinfectants constitute a particularly important group of hazardous chemicals, since they are used in large quantities and are often corrosive. Chemical residues discharged into the sewage system may have toxic effects on the operation of biological sewage treatment plants or on the natural ecosystems of receiving waters. Pharmaceutical residues may have the same effects, as they may include antibiotics and other drugs, heavy metals (such as mercury), phenols and derivatives and other disinfectants and antiseptics. 31. The severity of health hazards for health-care workers handling cytotoxic waste arises from the combined effect of the substance toxicity and the extent of exposure that may occur during waste handling or disposal. Exposure to cytotoxic substances in health care may also occur during preparation for treatment. The main pathways of exposure are inhalation of dust or aerosols, skin absorption and ingestion of food accidentally in contact with cytotoxic (antineoplastic) drugs, chemicals or waste, or from contact with the secretions of chemotherapy patients. 32. In most developing countries, chemical and pharmaceutical wastes are either disposed of with the rest of municipal waste, or sent to cement kilns for burning. Incineration is often regarded as the safest option to dispose of obsolete pharmaceuticals in developing countries. Most small-scale medical waste incinerators are not, however, equipped with the complex air pollution devices needed to keep dioxin emissions to the levels recommended by the Stockholm Convention (see paragraph 69 below). A significant amount of chemicals and pharmaceuticals is also disposed of through hospital wastewater. In countries where no wastewater treatment facilities exist, effluents from health-care facilities are discharged directly in rivers and other water streams, and risk contaminating surface and groundwater resources used for drinking and domestic purposes (see paragraph 55 below). 4. Mercury waste 12 13 World Health Organization, Health-care waste management, fact sheet No. 281, October 2004. World Health Organization, Core principles (see footnote 8). 9