Regulations for the prohibition of asbestos have been promulgated in terms of the Environmental Conservation Act, prior to the Waste Act coming into force. These regulations effectively declare asbestos as a priority waste.  Due to the transitional arrangement in section 80(2) of the Waste Act, these regulations remain effective. Wastes to be considered for declaration as priority wastes include polychlorinated biphenyls (PCBs) and mercury waste. PCBs are organic compounds which were widely used in transformers, capacitors and coolants. They are highly toxic, and easily penetrate the skin. Their destruction through treatment processes is difficult and often extremely hazardous. PCBs are classified as a persistent organic pollutant under the Stockholm Convention, to which South Africa has acceded as described in Section 1.4.

Mercury is a chemical element, most commonly used in scientific apparatus, CFLs and batteries. Mercury is highly toxic, and can cause severe poisoning, debilitating neurological conditions and in some instances death. Pollution of water sources by mercury causes serious ecological damage. The use of mercury is severely controlled in several countries.