The employer must ensure:
Each employee less than 4 feet (1.2 m) above dangerous equipment is protected from falling into or onto the dangerous equipment by a guardrail system or a travel restraint system, unless the equipment is covered or guarded to eliminate the hazard.
Each employee 4 feet (1.2 m) or more above dangerous equipment must be protected from falling by:
Guardrail systems;
Safety net systems;
Travel restraint systems; or
Personal fall arrest systems.