Ways of preventing loss of hearing due to noise exposure on the job were reviewed. Participants in the October 1986 National Symposium on the Prevention of Leading Work-Related Diseases and Injuries indicated that the most effective way to prevent hearing injuries from noise exposure was through engineering source controls. Such controls reduced the sound at its origin, and was most effective and cost efficient in the planning stage rather than in the operation stage. Some of the approaches included substitution of materials, modification of various processes, isolation of the processes, and monitoring. Material substitution called for replacing one material with a second material less prone to vibration. Fabric upholstery on chairs, for example, absorbs more noise than vinyl covered chairs. Process modification was successfully applied in the printing industry and in the casting of metal products. Modification of equipment was tried with success in the redesign of saw blades, better designed valves, and the installation of diffusers in control systems that vent to the atmosphere. Process isolation made use of sound absorbent linings on inner surfaces of equipment and sound barriers that absorbed generated noise. Monitoring provided needed feedback so that the effectiveness of the various control methods could be discerned and areas where additional work was needed could be identified. The author concludes that the ongoing thrust to eliminate work related hearing loss is best accomplished by procuring the quietest models of the latest equipment when making new purchases.