Fatality: Trapping in machinery

A member has reported the following severe accident during the inspection of a generator engine resulting in loss of life.

The incident occurred in a large (12m x 3m) container, weighing 40,000kg and holding a Detroit Diesel V16 generating set, a compressor, welding sets and two electrode ovens. The container was normally used for providing independent power for welding operations, for which purpose it would be lifted onto platform jackets.

On this occasion, it was decided to use the container for testing winches, rather than trailing 440V cables across the deck from crane tubes – the usual source of deck power.

When the generator was running, it would be very hot and noisy inside the container, with a large throughput of air being continuously drawn in.

Operators understood from a fluctuating engine note that there was a problem with the engine of the power generator and a deck team was sent to investigate. The team comprised a mechanical assistant (the team leader) and two motormen. All were experienced personnel, having at least ten years’ experience each on the semi-submersible crane vessel involved.

The team inspected the engine and decided to change the filters. This involved needing to shut down the generator and a deck electrician was called.

While one motorman and the deck electrician remained by the control panel, the other motorman and the mechanical assistant first adjusted the engine revolution using the remote control and then went to the side of the generator to check the fuel filters, as the filter bowls had shown evidence of water contamination (as had occurred on similar previous occasions). Changing the filters was considered a routine task and did not require a permit to work.

The mechanical assistant returned to the control panel to ask the motorman there to fetch new filters from the store. He then went outside to instruct the winch crew to stabilise the winches, as the generator was to be shut down so that the filters could be changed.

The second motorman remained inside, with the engine still running. As his colleague went to the store, the motorman inside the container was seen bending over with his hands on his knees, near the filters.

The deck electrician left his position by the control panel and went outside the container to see what was happening with the winches. On hearing some strange noises from the container, he went back inside and saw the motorman in a sitting position on the engine frame, with his back against the radiator mesh. He appeared to be looking under the engine. He again left the container, but a few seconds later, anxious about his colleague, went back in and saw the motorman in the same position. Knowing something was wrong, he shouted for help.

The deck electrician opened the circuit breaker whilst the mechanical assistant, who had re-entered upon hearing the shout for help, shut down the generator using the emergency stop.

In preparation for the filter change, the motorman had partially removed his jacket, releasing his right arm first. The suction created by the fan pulling air in from outside the container pulled the free part of the jacket and the motorman’s left hand, which was still inside the jacket sleeve, was pulled into the unguarded balance wheel pulley assembly. He suffered a traumatic amputation of his left arm below the elbow and a fractured skull as a result of the contact of his head with the cylinder block or exhaust manifold. He later died from his injuries.

Those in charge took the following actions:

  • medical intervention and treatment was performed by the on-board team with the client’s support and the MEDEVAC procedure was then immediately activated;
  • the engine was shut down, access to the container was restricted to authorised personnel only and specific stoppage signs were placed;
  • the guard to the ventilation fan was removed in order to recover the clothing and any possible part of the injured person for passing to the MEDEVAC team. The area where the injured person was found was searched for the missing portion of his arm, in case it could be saved.

The subsequent investigation identified the following root causes:

  • there was no specific written procedure for this kind of operation, other than the operating manual provided by the system and, in particular, engine manufacturers. It was considered a ‘normal’ inspection and maintenance operation, where common sense and normal operation required a shutting down of the system before any maintenance was started
  • an approach being followed by the team involved. In fact the incident occurred immediately before the engine was due to be switched off and the maintenance (filter change) carried out;
  • the motorman had been wearing a jacket and safety helmet, as per the company’s procedures, but it is likely that he removed them in order to prepare himself and be more comfortable, particularly in the warmer environment in comparison to the external weather, for the operation to be performed;
  • as this was considered a routine maintenance job and with the motorman being very skilled and confident with the job, it is thought likely that he had not considered the hazards related to the removal of his personal protective equipment (PPE) and the suction from the ventilation system. In this particular case it is considered that the motorman may have misjudged the potential hazards and relevant risk;
  • existing guards, warning or safety devices were in place in the area where the operation was to take place. However, the container was provided to the vessel over 15 years before, with no modifications having been made, and it is likely that the general safety device regulations and considerations of the manufacturer were less sophisticated than they would be today;
  • the pulleys and belt used to transfer the rotating motion to the ventilation/cooling system were improperly guarded and nobody had noticed or reported to management the hazard the un-protected pulleys posed;

The following contributory factors and other hazards were also identified:

  • the container had not been properly provided with safety signs and had no indication that only authorised personnel were permitted to enter, although there was a warning system providing information to personnel outside on the running of the engine and any mechanical emergency situation that may have arisen;
  • the high level of noise in the container created difficulties in communication between personnel inside the container, with main communication done by hand signals;
  • personnel working within the access way were in close proximity of the engine exhaust, presenting hot surfaces requiring protection;
  • the temperature inside the container was warmer than in the external environment;
  • access and egress were restricted and the working area was cramped – operators had to walk along a corridor approximately 70cm wide to reach the fuel filters (where the incident occurred); a battery rack alongside the container wall adjacent to the engine further reduced access and egress.

The company involved has noted the following actions as a result of its investigation:

  • protective devices to be fitted to the rotating parts on the generator and engine, in particular close to the ventilation/ cooling system;
  • protective devices to be installed for the hot surfaces of the engine, such as the exhaust manifold, which may come into contact with operators;
  • the battery package to be moved into a less congested area;
  • safety signs, such as ‘authorised personnel only’ and ‘hearing protection required’ to be placed at the entrance of the container, along with the normal PPE requirements;
  • access to the emergency stop for a standby person supporting the inspection operation to be checked;
  • an overall verification of on-board equipment and machinery with regard to guarding or protection of rotating and moving parts to be performed by competent persons;
  • vessel management to perform a survey identifying all operations and relevant PPE to be used;
  • safety helmets to be kept on in all work sites, with chin straps utilised in order to avoid loss of helmet when changing posture or environmental conditions;
  • management to emphasise the need to maintain a high level of attention when performing routine operations, noting that routine operations are normally those that create overconfidence.

It has also adjusted its procedures as follows:

  • inspection operations beyond the control panel now require a standby person in attendance within the immediate area of the emergency stop and where they can easily see the inspection operators;
  • lone working beyond the control panel or when the engine is in operation are not allowed and a review of other areas where lone working should not be allowed to be undertaken, in addition to existing permit-to-work areas;
  • a weekly safety walk-through of the work site is to be implemented on-board, with the management team visiting different areas of the vessel in rotation to monitor equipment/safety conditions in work areas and a log of identified actions and subsequent implementation to be kept by safety personnel;
  • safety personnel to ensure that ‘normal’ operations are adequately assessed, with job safety analyses available to maintain a high level of awareness and performance monitoring for such operations. All personnel to be involved in the identification of hazards and assessment of relevant risks for routine operations, other than project-specific operations;
  • a safety observation system to be implemented on-board, with encouragement given to workers to report all situations which may lead to safety problems and management obliged to provide immediate feedback on proposed actions, but avoiding ‘identification of breaches of procedures by other persons’ in order to promote a ‘no blame’ culture.