He spent his career documenting collective trauma. Grassy Narrows was one of his toughest cases

Kai T. Erikson, Yale sociologist who dedicated his career to documenting the collective trauma faced by communities in the wake of unimaginable disasters, has died at the age of 94. In the late '70s, he spent time collecting the stories of people on Grassy Narrows First Nation suffering from the impacts of mercury poisoning.