Isolate, de-energise, lockout and tagout plant before maintenance

Background 

An incident has occurred where a quarry maintenance employee was removing screens from a mobile screening plant. This task required the employee to work on the output conveyor of the plant.

During the maintenance activity another quarry employee started the screen plant to loosen grass caught in the screen. The employee working on the screen was ejected from the plant when the conveyor started, and was impaled by a 60 cm long metal tool around his chest and shoulders, resulting in significant injuries. The injured employee was taken to hospital in an air ambulance.

Safety issues

Hazards that can lead to accidentally activating plant or stored energy being released by plant include:

• The screen plant can be operated with the output conveyor in the lowered position.
• No engineering control or other higher order control on the plant to prevent the plant from being started and operated when employees are standing on the conveyor.
• Plant not de-energised before maintenance activities commencing.
• The site Lock Out/Tag Out system was not used for mobile plant maintenance.
• No verification that all employees are at a safe distance before re-starting the plant.

Recommended ways to control risks

To manage the risk of employees being injured, employers should:

• install limit switches, interlocks and or other higher order controls that prevent plant from starting when people are on or in the plant doing maintenance activities
• provide an isolation procedure that has a provision for the physical lock out, tag out and de-energisation of plant during maintenance activities
• ensure that all employees who interact with the plant are aware of maintenance activities being undertaken
• ensure a thorough and accurate risk assessment is developed in consultation with impacted employees, for activities which requires de-energisation, and maintenance on plant.

Legal duties

Employers have responsibilities under the Occupational Health and Safety Act 2004 to ensure they provide a work environment that is safe and without risks to health, so far as is reasonably practicable. The OHS Regulations require that hazards associated with the use of plant be identified and actions taken to control risks. The legislation also places duties on designers, manufacturers and suppliers of plant.

Specific duties under the Occupational Health and Safety Act 2004 (OHS Act) include to:

• provide and maintain a working environment that is safe and without risks to the health of employees and contractors, so far as is reasonably practicable — that includes fit for purpose plant and systems of work
• where a risk cannot be eliminated, reduce the risk so far as is reasonably practicable
• provide the necessary information, instruction, training or supervision, including how to identify handling hazards and safely operate mobile plant, to enable employees to do their work in a way that is safe and without risks to health
• consult with employees, contractors and health and safety representatives, where present, when identifying hazards and risks
• consult with employees, contractors and health and safety representatives, where present, when implementing controls to eliminate hazards and risks or, where not reasonably practicable to do so, minimise them
• review and revise any measure implemented to control risk.

Wherever reasonably practicable, higher order controls such as elimination, substitution and engineering must be implemented.