27 April 2015 / #city of ottawa #flags City flags at half-mast for National Day of Mourning for Persons Killed or Injured in the WorkplaceThe flags at all City of Ottawa sites will be lowered to half-mast from sunrise to sunset on Tuesday, April 28 to commemorate the National Day of Mourning for Persons Killed or Injured in the Workplace (Workers' Mourning Day). This day, to memorialize lives lost in the workplace and to resolve to prevent future tragedies, was officially recognized by the federal government in 1991, and has since spread to about 80 countries around the world.