This testimony concerned the activity of NIOSH in the field of repetitive trauma disorders. Such disorders were a class of musculoskeletal disorders involving damage to the tendons, tendon sheaths, and the related bones, muscles, and nerves of the hands, wrists, elbows, arms, feet, knees, legs, neck and back. Diseases associated with such disorders included carpal tunnel syndrome, tendinitis, tenosynovitis, DeQuervain's Disease, low back pain, and vibration induced Raynaud's syndrome. Such injuries have occurred as a result of repeated harm, not isolated accidents. Since 1984 the numbers of such reported injuries have doubled, exceeding 72,900 cases in 1987, and accounting for up to 39 percent of all occupational illnesses reported to OSHA in 1987. Manufacturing industries had the highest rate, with the five highest manufacturing industries being meatpacking, manufacturing and household appliances, rubber and plastic footwear, office and furniture fixtures, and motor vehicles and equipment. A manual was developed by NIOSH which identified cumulative trauma disorders (CTDs) of the upper limbs and identified risk factors, evaluated jobs and records and surveyed workers to determine if a problem was occurring, and provided guidelines for protecting workers in jobs that pose a serious risk. Current research programs in this area were described.