Working at heights is not always up there on a roof or high structure. Working beside a pit or trench could mean falling to below ground level.
falling to ground or below ground level from height is serious, but we must take into account what a person could fall onto or into. for example reinforcing steel standing up out of concrete can be very serious indeed to fall onto.
falling into a container of chemicals, or a hopper with mechanical action are other very serious examples.
consideration of what we could fall onto or into must be discussed and eliminated or controlled to minimum.
safety is everyone's business