Flour mill grain silo engulfment

Tick each point that your answer made clearly and only once. Points here are this site's own. A real examiner may accept other valid points.

• A risk assessment identifies what could cause harm, who could be harmed and what precautions are needed, so that the risk can be controlled.
• The assessments at Crescent were made when the mill was built and have not been reviewed since the silo was extended and a second auger was installed.
• They do not mention the silo, the entry into the silo or dust, although these are the most serious hazards on the site, so the hazards were not identified.
• Identify the hazards: collapse of bridged grain or wall deposits, flowing grain, moving augers, falls at the hatch and damaged ladder, dust inhalation and explosion, possible oxygen deficiency or toxic gases, and delayed rescue. A normal oxygen reading would not remove the engulfment risk.
• It should identify who may be harmed, including the workers who enter, the people at ground level, the casual workers and the rescuers.
• It should evaluate the risk, taking into account the likelihood and the severity of harm, and the controls that exist, such as the auger switch, which was not locked.
• The near miss in month 2, when a worker slipped into the grain, and the auger incident in month 3 showed that serious harm was likely and the risk was known.
• First assess how to avoid entry altogether. Have competent specialists assess a method of clearing blockages from outside without exposing anyone to moving grain, falling deposits, machinery or dust; do not improvise with air blasts or poles.
• The assessment should be done by a competent person with the help of workers who do the task and who know the real practices.
• The significant findings should be recorded, and an action plan with owners and dates should be prepared.
• The assessment should be reviewed after every change to the plant, after incidents and near misses, and at planned intervals.
• Crescent should communicate the results to the workers and the casual workers, and should check that the controls are used.

Practice points counted: 0 of 12

Tick each point that your answer made clearly and only once. Points here are this site's own. A real examiner may accept other valid points.

• Stop the practice of sending workers onto grain to restore flow. Review grain condition, storage and maintenance with competent specialists to reduce recurring blockages and the need for entry.
• Have a competent specialist plan blockage removal from outside, with people kept clear of collapse and discharge areas. A pole through the top hatch is not a safe method if the worker must lean into the opening or stand on grain.
• If a different task genuinely requires entry, first assess whether it can be done without entry. Any unavoidable entry needs a site-specific confined-space safe system, competent authorisation and emergency arrangements; a permit does not make a grain bridge safe.
• Before authorised entry, isolate and secure every source of dangerous energy and material movement, including both augers, the bucket elevator, grain inlet and outlet. Verify isolation, including stored energy and gravity-fed material; switching off the ground-level panel is insufficient.
• Where an authorised entry requires a harness and lifeline, use a properly designed and anchored system selected by a competent person. An attendant holding a rope is not an adequate substitute. This equipment does not authorise entry onto bridged grain or guarantee rescue.
• Do not walk down grain to make it flow, stand on moving or bridged grain, or enter beneath a bridge or unstable wall deposits. Boards laid on grain do not remove the collapse or engulfment hazard.
• A competent person should assess and test for oxygen deficiency and relevant toxic or flammable contaminants, provide suitable ventilation and monitoring, and define stop and evacuation conditions before any authorised entry. Dust masks do not supply oxygen.
• Repair the ladder and the hatch, keep the access safe, and put up signs and barriers that warn of the danger and stop unauthorised entry.
• Control the dust at its source with extraction, enclosed conveyors and hoppers, and by reducing the fall of grain from a height.
• Use a planned housekeeping programme and an industrial vacuum system suitable for the combustible dust and the area classification. Avoid dry sweeping and compressed-air cleaning that disperses dust; a domestic vacuum is not a substitute.
• Control exposure at source, then select suitable respiratory protection for remaining dust exposure, with training and face-fit testing for tight-fitting masks. Arrange risk-based respiratory health surveillance for grain-dust exposure. A particulate mask cannot protect against oxygen deficiency.
• Control sources of ignition in areas with dust, with suitable electrical equipment, hot work controls and the correct use of tools.

Practice points counted: 0 of 12

Tick each point that your answer made clearly and only once. Points here are this site's own. A real examiner may accept other valid points.

• The silo is largely enclosed and the scenario describes a foreseeable risk of suffocation in grain, making confined-space precautions necessary. Its size or an open hatch does not remove that risk; assess atmospheric hazards as well.
• There was no written procedure for entry, so the workers relied on custom and the instructions of the supervisor.
• There was no permit to work, which is a formal check that the precautions are in place before the work begins.
• There was no isolation of the auger, so the grain was able to move while the worker was inside.
• There was no harness or lifeline, no atmosphere test, and no trained person at the entrance to watch.
• There was no rescue plan or equipment, and the breathing apparatus was kept in the office without training.
• Avoid entry, particularly for clearing a grain bridge. Stop any proposed entry onto or beneath bridged grain or where wall deposits could collapse; neither a permit nor a harness overrides this restriction.
• For an unavoidable, separately assessed entry task, use a permit recording the scope, hazards, verified controls, authorised people, validity period and evacuation arrangements. A competent issuer should verify conditions; suspend the permit if conditions change.
• The entry system should identify, isolate, secure and verify all dangerous equipment and material routes, including the added auger, elevator, inlet and outlet. Control stored energy, gravity flow and restart by others, rather than relying on one switch or tag.
• An attendant should be stationed outside, in contact with the person inside, with the authority to order a stop and to raise the alarm, and who never enters to rescue.
• A trained person should use suitable, calibrated and checked instruments to assess oxygen and relevant contaminants before entry and monitor as the assessment requires. Plan ventilation and evacuation triggers; acceptable gas readings do not prove grain is stable.
• Workers should be trained and competent in the entry, the use of the equipment and the emergency procedure, and casual workers should not enter until they are trained.
• Before entry, establish and practise rescue arrangements suited to this silo, its access and the hazards. Use non-entry recovery where feasible, with properly selected equipment and competent rescuers. A tripod and winch alone do not establish that an engulfed person can be recovered safely.
• The permit should be closed when the work is done, with a check that nobody is left inside, and the system should be audited.

Practice points counted: 0 of 14

Tick each point that your answer made clearly and only once. Points here are this site's own. A real examiner may accept other valid points.

• The bonus for output and the message that stoppages cause losses show that production is put before safety.
• There are no figures for near misses, and the accident book is in the office, so the reporting culture is poor.
• The unsafe practice of entering the silo without precautions was tolerated by supervisors and managers, and the near misses in months 2 and 3 were not followed up.
• The safety policy is ten years old and names no one, and the safety officer's duties were given to a manager with a production role, so responsibilities are not clear.
• Casual workers fear that they will lose their work if they refuse a task, so they do not feel able to raise concerns.
• Senior managers should set out a clear policy that safety comes first, and should name who is responsible for each task.
• Managers should change the targets and the bonus, so that safety measures are included and output is not rewarded at any cost.
• Managers should be visible on the site, take part in the safety meetings and act on the reports of workers.
• They should appoint a competent safety adviser who is independent of production and has the authority to stop unsafe work.
• They should consult workers and casual workers on safety, and set up a way to report hazards without any penalty.

Practice points counted: 0 of 10

Tick each point that your answer made clearly and only once. Points here are this site's own. A real examiner may accept other valid points.

• Casual workers are often new to the site and the work, and they are less likely to raise concerns, so the risk to them is higher, and Crescent owes them the same duty as to its own employees.
• Crescent should agree in writing with the labour contractor who is responsible for training, protective equipment and supervision.
• Crescent should tell the contractor about the hazards of the work before the workers arrive, and give notice of its need so that preparation is possible.
• Induction should be given before work begins and should include the layout of the mill, the hazards, the rules, the emergency arrangements and who to report to.
• Induction should be in a language that workers understand, with pictures, demonstrations and written material.
• Job specific training should be given before a worker is allowed near the silo, the augers or the dust, and tasks such as silo entry should be limited to trained and authorised people.
• Protective equipment should be given on the first day, and workers should be shown how to use it.
• Supervisors should be trained for their role, including the supervision of workers who are new, and they should be told that they must not order a worker to do an unsafe task.
• A named person should be responsible for casual workers on each shift and should check that they understand the rules.
• Crescent should explicitly protect workers who stop or refuse unsafe work from retaliation, explain how to raise concerns, and check that supervisors and the labour contractor follow that policy. Specific statutory rights depend on local law.
• Training should be recorded and checked, and refreshed at intervals.
• Crescent should monitor the record of the contractor and choose it on its safety performance, not only on its price.

Practice points counted: 0 of 12

Tick each point that your answer made clearly and only once. Points here are this site's own. A real examiner may accept other valid points.

• Emergency arrangements should be based on the risk assessment and cover foreseeable events, such as a person trapped in the silo, a fire and a dust explosion.
• A written emergency plan should name those with roles, such as the incident controller, the rescue team and the person who calls the services.
• At Crescent there was no rescue plan for the silo, so two workers entered without equipment and one of them became a casualty.
• Before any authorised entry, establish a silo-specific rescue plan with competent, available rescuers, suitable maintained equipment and rehearsed communications. Select retrieval equipment and any breathing apparatus through the assessment; the unused office set is not a rescue arrangement.
• Raise the alarm, summon specialist rescue assistance and prevent further entry. Only a designated, trained and equipped rescue team should undertake rescue entry under the plan. Breathing apparatus does not protect against engulfment, and a winch is not a plan for freeing someone trapped in grain.
• The alarm should be heard and understood in every part of the site, including the top of the silo, and should be tested.
• Emergency numbers should be correct, displayed and known, and one person should be responsible for keeping them up to date.
• Drills should be held at regular intervals and the results used to improve the plan, and there had been none since the mill was built.
• First aid should match the risk of the work, with trained first aiders on every shift and a first aid room or equipment in a suitable place.
• First aid equipment should be kept near the places of risk and not only in the office.
• Liaise with specialist rescue and emergency medical services before work, confirm access and communication arrangements, and account for their response time. A call to the ambulance service alone is not an adequate silo rescue plan.
• Because the hospital was 40 minutes away, there should be a plan for the transport of the injured and for care in the meantime.
• After an emergency, the site should be made safe, evidence should be preserved, and the incident should be investigated.
• Workers should receive support after a traumatic event, and the plan should be reviewed.

Practice points counted: 0 of 14

Tick each point that your answer made clearly and only once. Points here are this site's own. A real examiner may accept other valid points.

• The aim of an investigation is to find out why the incident happened, so that a repeat can be prevented, and not to find someone to blame.
• Arrange emergency care and make the scene safe before gathering evidence. Preserve the auger controls, isolation arrangements, access condition and any entry or rescue equipment without exposing investigators to the silo hazards.
• Information should be gathered from the scene, photographs, the maintenance log, training records and statements from witnesses.
• The investigation team should include a manager, a supervisor and a worker representative with the right competence, and outside help may be needed because of the seriousness.
• Witnesses should be interviewed soon, separately and with care, since several are in shock.
• The team should analyse the facts to build a timeline and should look for immediate, underlying and root causes.
• Immediate cause: the worker entered the silo while the auger was not isolated, and another worker started the auger without knowing that a man was inside.
• Immediate conditions included entry onto a grain bridge, its collapse when the auger started, and unplanned rescue entry. Missing isolation, entry controls and rescue arrangements contributed; a harness alone would not establish that the incident could have been safely rescued.
• Underlying cause: there was no safe system of work or permit for entry into the silo, although the task was done regularly.
• Underlying cause: the supervisor ordered a casual worker with no training to do a dangerous task under pressure to meet output.
• Underlying cause: the earlier near misses were not reported or acted on, and the risk assessment did not cover the silo.
• Root causes include poor safety culture, with output rewarded above safety, unclear responsibilities and no competent safety adviser.
• The team should make recommendations with an action plan with owners and dates, and should follow up to check that they are done.
• Crescent should report the incident to the authority as required by law, inform the family and share the lessons with the workers.

Practice points counted: 0 of 14

Tick each point that your answer made clearly and only once. Points here are this site's own. A real examiner may accept other valid points.

• Moral: a worker died in the silo and another is in intensive care, and nobody should be killed or injured by their work.
• Moral: the family of the dead worker has lost income and a loved one, and the workers who saw the event may suffer lasting distress.
• Moral: Crescent owes a duty of care to casual workers as much as to employees, and these workers are often the most vulnerable.
• Legal: employers must provide safe plant, safe systems of work, information, instruction, training and supervision, and must assess risk.
• Legal: the failures at Crescent, such as no safe system for entry and no isolation, are likely to be breaches of these duties.
• Legal: the authority may inspect the mill, issue a notice, or prosecute, and the managers may be personally liable.
• Legal: the family or the injured worker may bring a civil claim for compensation.
• Financial: the direct costs include lost production while the silo is closed, the investigation and the cost of repairs.
• Financial: fines, compensation and a rise in insurance premiums can be large.
• Financial: the loss of orders and a bad reputation among farmers, customers and workers can be costly, and some costs cannot be recovered.
• Financial: good safety management reduces such losses and improves efficiency, morale and the retention of workers.
• Reputation: a fatal incident draws attention from the public, the media and the regulator, and may affect the relations of Crescent with its customers.

Practice points counted: 0 of 12