Abstract: The effectiveness of bleach in inactivating HIV in drug users’ injection equipment is in question. In a letter to the editor published in the American Journal of Public Health, Harvey Siegal et al respond to the report by Shapshak and his colleagues that a minimum of 30 seconds in bleach is needed for sufficient cleaning of the equipment. Through their own observations of 77 intravenous drug users, Siegal et al noted a great disparity in the amount of bleaching time–from 1 to 75 seconds–as well as in the methods of cleaning of the equipment. Despite the fact that the study was conducted in project offices, the results provide some evidence of how drug users really use bleach when cleaning. It is important to clearly state disinfection techniques in prevention messages that target drug users, because a few seconds’ difference can make all the difference between becoming infected with HIV or remaining uninfected.