Abstract: Both medical screening (detection of early adverse health effects at a stage when secondary prevention can be implemented) and medical surveillance (review of adverse events to trigger hazard identification) are important components of occupational safety and health programs. Systems that promote effective communication are central. General safety and health programs that include management commitment, employee participation, hazard identification and control, training and program evaluation promote healthy workplaces and prevent senseless waste of effort as well as needless illness and injury. Case examples of lost opportunities that range in severity from mild exposures to occupational fatalities will be examined. Fatal examples are drawn both from industrial and from university research settings. This session will explore ways in which effective safety and health programs might have averted these tragedies.