Following guidelines issued by the Centers for Disease Control, the Clinical Center implemented a Universal Precautions policy in November 1987 in an attempt to reduce healthcare workers' risks for occupational exposures to bloodborne pathogens. All hospital personnel whose jobs entailed potential exposure to patients' blood and body substances were required to attend a training session and complete a written examination. Based on data from surveys conducted before and twelve months after training in Universal Precautions, the frequency of cutaneous exposure to blood decreased by 50% in temporal association with implementation of Universal Precautions. Staff at the Clinical Center are required to take a refresher course in Universal Precautions annually.