Previous authors have argued that trust may be based on the extent to which risk communicators are seen as good at discriminating safety from danger, are unbiased in their assessments, and share their audience's values. Residents of two English urban regions rated their trust in six potential sources of information about the risk of contaminated land in their neighborhood (independent scientists; local council property developers; residents' groups; friends and family; local media), and how expert, open, accurate, or biased these sources were and how much they had residents' interests at heart. Overall, scientists were trusted most and developers least, but this was only partly due to their greater perceived expertise. Resident groups and friends/family were also trusted, despite being seen as relatively inexpert, since they scored highly on openness and shared interests, these latter two attributes being more important predictors of trust in individual sources than perceived expertise. We conclude that, where a source is seen as motivated to withhold, distort, or misinterpret information, this will undermine public trust even in apparently knowledgeable sources, hence supporting the view that trust depends on a combination of perceived expertise and perceived motives as complementary processes.