Summary:To evaluate the effectiveness of bleach disinfection of injection equipment, we tested HIV-1 inactivation by household bleach in needles and syringes. We obtained blood from HIV-1 infected injecting drug users (IDUs), placed small aliquots in needles and syringes. Blood with and without anticoagulant was incubated at room temperature for 3, 6, 18, and 24 h, and some needles and syringes from each condition were exposed to undiluted bleach for 15 and 30 s. The needles and syringes were then rinsed and the rinses were used to inoculate peripheral blood mononuclear cells (PBMNCs). HIV-1 replication was monitored using p24 enzyme linked immunosorbent assay (ELISA). We describe results that HIV-1 is inactivated in clotted and unclotted blood allowed to stand at room temperature for 3,6,18, and 24 h in needles and syringes using undiluted household bleach at 30 s of exposure time. These results are consistent with earlier findings that micropellets of HIV-1 were inactivated by bleach under similar conditions of exposure to bleach; 10% bleach was not effective at an exposure time of 30 s and undiluted bleach was not effective at an exposure time of 15 s to inactivate HIV-1 in clotted blood. Bleach concentration and exposure time are critical and HIV disinfection may not occur with inadequate exposure to bleach HIV.