More than 140 nations will meet next month in Japan to formally adopt the Minamata Convention on Mercury. It calls for phasing out a wide range of mercury products and curbing emissions from major sources. It also aims to bolster efforts to tally and track mercury emissions. And it contains unusual language calling on nations to make special efforts to monitor the health of people exposed to the toxin. Improving emissions and health monitoring efforts, however, could be a tall task, and researchers will face some challenging questions about how to proceed.