OSH alert - excavation near miss (December 2015)

Key learnings from a High Potential Incident


HPI OSH Alert #472

Date of incident: 01 December 2015

Safety Flash issued: 10 December 2015 


What happened?

Photo of excavation

Three contractor’s employees were working in an excavation for a gravity sewer approximately six metres deep. The excavation was not benched, battered or shored to the Construction Engineer’s approved excavation plan and presented a high risk of excavation collapse.

Why did this happen?

  • The excavation was not carried out in accordance with the Construction Engineer’s approved excavation plan.
  • The contractor’s procedure for safe management of deep excavations was not followed.
  • Poor planning and work scheduling - construction of the wet well and valve pit was accelerated to meet mechanical installation before the inlet sewer was installed.
  • Inadequate management of change including poor communication and feedback regarding client variation request.
  • Time/productivity pressures – the project was already behind schedule and due to the impending wet season, workers were trying to undertake all excavation work as quickly as possible.
  • Inexperience leading to poor decision making – this was the Site Supervisor and Construction Engineer’s first wastewater pump station construction project.
  • Poor hazard perception and identification – the majority of the crew including the Site Supervisor did not deem the excavation to be hazardous.

 What will the contractor involved in the incident do to stop this from happening again?

  • Publish a memorandum from management to all sites reinforcing to workers that production will not supersede safety processes and procedures.
  • Apply the performance and behaviour model to all employees who were working on the excavation.
  • Conduct “Take 5” training for all field staff with a focus on risk management.
  • All excavations are to be formally approved in writing by the Principal Engineer pending implementation of a formal and robust excavation permit system.
  • Develop and implement a fortnightly detailed work planning schedule across all contractors’ major projects.

What will our organisation do to stop this from happening again?

  • Reinforce to Contract Managers and Supervisors that production will not supersede safety process and procedure.
  • Confirm that the contractor has implemented all corrective actions to a satisfactory level.

Your action:

What key learnings can you discuss with your team to stop this from happening again?

Excavations greater than 1.5 metres deep are considered as High Risk Work areas under Western Australian Occupational Safety and Health Regulations 1996.

  • Are we aware of this?
  • Do we have any workers or contractors conducting any excavation works in our area?
  • Do we know what work methods are required to provide the required protection e.g. trench boxes?
  • Did you know there is an Excavation Safety Awareness course available to field operators required to dig in or around excavations? See LMS for more details.

It is crucial to have competent people working in and around excavations.

  • Who in our team is competent to work in and around excavations?
  • Do those identified have a clear understanding of the hazards and risks associated with the task?
  • Do those identified have a clear understanding of the scope of their responsibilities and authority?
  • What information does a competent person need to be able to effectively plan and conduct a safe excavation?

It is critical to ensure that all controls identified in the JSEA are implemented. Production priorities do not override the need for proper planning and safety requirements.

  • What should we do if we observe potentially unsafe situations at work?
  • When a planned task changes, do we stop and assess the risk and update safe job planning documentation with the new hazards and controls?

Further information

If you would like further information about anything included in this HPI OSH Alert, please contact Charis Neumann, Snr OSH Analyst – Incidents, (08) 6330 6629