Injuries with used needles and other "sharps" put health care workers at risk for serious bloodborne infections, such as HIV and hepatitis B and C. To some extent, this risk can be lessened through safer techniques (such as not recapping needles) and safer devices (such as needleless and self-sheathing equipment). But these injuries occur within a context (often a hospital unit) with organizational features that may themselves contribute to an increased or decreased risk. This Issue Brief summarizes a series of studies that investigate whether workplace aspects of the hospital (such as staffing levels, and organizational structure and climate) affect the risk of needlestick injuries to nurses.