This paper describes a novel collaborative machine translation (MT) plus post-editing system called PHAST (Public Health Automatic System for Translation, phastsystem.org), tailored for use in producing multilingual education materials for public health. Its collaborative features highlight a new approach in public health informatics: sharing limited bilingual translation resources via a groupware system. We report here on the design methods and requirements used to develop PHAST and on its evaluation with potential public health users. Our results indicate such a system could be a feasible means of increasing the production of multilingual public health materials by reducing the barriers of time and cost. PHAST's design can serve as a model for other communities interested in assuring the accuracy of MT through shared language expertise.