Refinery workers and brothers Ben and Max Morrissey were killed as they tried to fix a flammable liquid overflowing a fuel gas mix drum, federal investigators said.
"People should go to work and expect to go home the same way they went to work," Jim Witt, the president of USW 1-346, said at the Workers' Memorial Day event.
According to a source at the Cenovus Toledo Refinery, multiple units at the refinery are now open as part of a phased reopening plan expected to finish in mid-May.
Cenovus spokespeople said safety is a priority during a restoration project to prepare the former BP-Husky Toledo Refinery for a projected reopening in May.