Well-being is the ultimate objective of any labour movement. For long, efforts have concentrated on the provision of jobs and decent work conditions. Recently, however, labour economics has been focussing on health, in general, and mental health, in particular. It is time for labour economists to study this challenging issue. Typically, work is not the cause of poor mental health but, often, its cure. Decent work or earnings may help to avoid or moderate mental health issues. While in advanced societies the social effect of decent work may moderate illness, in developing economies sufficient earnings may pave the way out of natural causes of illness. This paper makes the case that natural arsenic poisoning of water affects the well-being of families negatively and causes substantial loss. Recent research for Bangladesh suggests that showing the symptoms of arsenic poisoning reduces well-being substantially. The impacts on mental health can be avoided or reduced through education and the relaxation of financial constraints on families. © 2016, Indian Society of Labour Economics.