The Oaks Colliery disaster killed at least 360 miners in December 1866 – just two weeks before Christmas – and was the world’s biggest industrial disaster of the 19th century, but it remained virtually unknown for 150 years. Even the names of all those who died were not documented until the local community tried to set the record straight and remember the victims of the tragedy. This resulted in (among other things) a documentary called Black Snow which won the Best Research Film of the Year award at The AHRC Research in Film Awards 2018. The director of Black Snow, Stephen Linstead and colleagues from different agencies who collaborated on the memorial project, explain why the men and women who have died in the course of their work, including those from accidents and disasters, should be commemorated on a special day