Possible health hazards associated with drilling monitoring wells at and around waste disposal sites were discussed. It is becoming increasingly important in the 1980's to monitor ground water. There is a need to determine what potentially noxious substances might be buried on site, what migration of these substances has occurred, and what future movements might occur. Wells to monitor the quality and movement of ground water in and around waste disposal sites are increasing rapidly to comply with solid and hazardous waste disposal laws. Approximately one million wells are to be drilled during the 1980's to monitor ground water. Drilling methods and techniques are critical to the success of monitoring wells, and such drilling procedures are frequently associated with hazards. Examples of dangers to workers include: explosive or flammable vapors, toxic or poisonous chemicals, and soil contaminated with toxic chemicals. Each driller must be continually aware of these dangers because the short term effect of these chemicals and vapors may seem small, but chronic effects can be very serious, contributing to cancer, a shortened lifespan or simply poor health. The authors conclude that safety precautions must be taken and that the refusal to wear proper safety equipment severely reduces worker safety.