THIS PAPER describes the hazards which can occur when dealing with four major classes of potential pollutants, namely paints, timber preservatives, formaldehyde and volatile organic compounds. Some of the conclusions are applicable to other potentially hazardous materials and the third section makes recommendations about the selection, application and control of toxic substances with specific reference to the South. The paper is intended to initiate a discussion about the problem of hazardous materials in the Third World especially where unfamiliar new materials are being used for the first time.