This guide recommends procedures for safe handling and disposal of hazardous substances, along with broad recommendations for developing comprehensive laboratory safety programs. Although specific information is provided, general principles which can be adapted to activities in any laboratory are emphasized. Section 1 focuses on procedures for working with chemicals in the laboratory including: (1) general recommendations for safe practices in laboratories; (2) procedures for working with substances posing hazards because of acute toxicity, chronic toxicity, or corrosiveness, for working with substances posing hazards because of flammability/explosibility, and for working with compressed gases; (3) known hazards of and specific precautions for selected chemicals; (4) protective apparel, safety equipment, emergency procedures, and first aid; (5) design requirements for and use of electrically powered laboratory apparatus; and (6) laboratory ventilation. Section 2 provides procedures for: (1) ordering/procurement of chemicals; (2) storing chemicals in storerooms/stockrooms; (3) distributing chemicals from stockrooms to laboratories; (4) storing chemicals in laboratories; (5) chemical disposal in laboratories; (6) special disposal problems in life science laboratories; and (7) disposal of waste materials from the institution. Evaluation of published epidemiological studies of chemists, recommendations for future studies, and threshold limit values for chemicals/physical agents in workroom air are provided in appendices. (JN)