<p> TOXIC AND RADIO-ACTIVE WASTE</p><p>Some chemical waste is very toxic and has to be dealt with extremely carefully. Pollution controls are now very strict. The most usual way of dealing with toxic chemicals is landfill sites, see diagram below.</p><p>OECD List of Hazardous Chemicals</p><p>RED LIST (Very dangerous – 60 day permit) Wastes containing PCBs, polychlorinated terphenyl, polybrominated biphenyl, chlorinated dioxins, asbestos, leaded anti-knock compound sludge.</p><p>AMBER LIST (Slightly less dangerous – 30 day permit) Ash from iron and steel manufacture, petrol, coke and bitumen, lead acid batteries, waste oils and oil/water mixtures, phenols, thallium compounds, hydrogen peroxide solutions.</p><p>GREEN LIST (Recyclable) Scrap metals: gold, platinum, silver, iron and steel, copper, nickel, lead, cadmium, indium, gallium, thallium. Plastics: PVC, polythene, polypropylene, styrene polymers, polyamides, Teflon, phenol-formaldehyde resins. Other: Ceramics, mining wastes, glass, rubber wastes, textiles and tannery wastes, gypsum, some ashes from coal-fired power stations.</p><p>RADIO-ACTIVE WASTE</p><p>Low level waste e.g. plastic bottles, disposable gloves, lab coats and hospital swabs can be dealt with in a toxic waste landfill.</p><p>Intermediate level waste e.g. isotopes from X-ray departments, industrial materials and decommissioned parts of a nuclear reactor have to be buried in deep secure repositories.</p><p>High level waste is either recycled or kept in glass containers buried in lead and concrete. Fortunately there is very little of this.</p>