Falls, engulfment and subsequent suffocation, entanglement in machinery, and exposure to silo gases, dusts, and moulds are some of the main safety risks and causes of silo injuries, illnesses, and deaths.
What do we mean by silo safety?
A silo is a large, tall, cylindrical structure used for storing bulk materials such as grain, sand, flour, fertiliser, or food for animals. Silos are made of many materials, including stainless steel, reinforced concrete, plastic, fibreglass, and wood.
They use less ground space compared to horizontal storage structures like sheds and warehouses. They can be closed or open. Closed silos are sealed from fresh air and store goods under optimal conditions, free from insects and pests.
Working with silos can involve working at heights, working in confined spaces, and working with machinery, and this presents a range of safety risks for workers.
What are the risks of silos?
The risks of working with silos are like the risks of working in other confined spaces on farms and rural settings, including storage tanks, field bins, wet and dry wells, vehicle service pits, and manure and silage pits. They can be dangerous, even for the most experienced workers.
Some of the risks of working with silos include:
- injury from noise, slips, trips, falls, and manual handling
- being overcome by fumes or gases
- explosions – the atmosphere can be dangerous, particularly if the humidity is low
- exposure to high temperatures, which can result in heat stress for anyone entering the silo.
Some of the other risks of working in confined spaces include:
- oxygen deficiency caused by grain absorption
- carbon monoxide build-up in wells from the exhaust of an operating internal combustion engine if located too near its opening
- the presence of contaminants in the atmosphere caused by disturbing decomposed organic material in a bin letting out toxic substances
- the build-up and release of gases like ammonia, methane, carbon dioxide, and hydrogen sulphide in manure pits
- suffocation caused by solids such as grain, sand, or fertiliser.
How do I manage the risks?
Workers and management can work together to reduce the risks of working with silos.
As a worker, you must:
- take care of your own health and safety as well as the health and safety of others
- cooperate with management to meet health and safety requirements and reduce risks.
As an employer or business owner, you have legal responsibilities as outlined in the Work Health and Safety Act 2011 for the health and safety of every worker and visitor.
The four-step risk management process below will help businesses to meet their responsibilities under work health and safety (WHS) laws.
You can also use the practical advice in the How to manage work health and safety risks code of practice 2021 (PDF, 0.65 MB).
Four steps to manage risk
The first step is to identify the hazards.
- Is the silo designed to suit the product its storing?
- Is there a regular maintenance program in place?
- Should silo entry be required, are workers trained and experienced in entering confined spaces?
- Are emergency plans, rescue teams and equipment available in the event of an accident?
Talk to your workers and ask:
- Are you aware of any potential hazards?
- How can we improve our safety and our processes?
- Do you know how to report a hazard?
Regularly review your own records, and consider:
- What do your workers’ compensation claims, recorded incidents, sick leave and worker complaints tell you about past incidents and hazards?
- What can you do to prevent the same things happening again?
Identifying hazards should be an ongoing activity and something organised at least once a year, or whenever there is a change in equipment, facilities, or work practices.
Next, assess the level of risk posed by each hazard. The risk level is determined by:
- how serious the potential harm is
- how likely it is to happen.
You can use this risk assessment template (DOCX, 0.02 MB) to guide you and record your assessments.
The law requires you to eliminate the risks if practical, or to minimise them as much as possible.
You must work through the hierarchy of controls to choose the control that most effectively eliminates or minimises the risks. This may involve a single control measure or combination of two or more different controls.
Find the hierarchy of controls in How to manage work health and safety risks code of practice 2021 (PDF, 0.65 MB) .
Have an emergency plan for someone being trapped.
Further ways to control the risks of working with silos include:
Design and installation
- locate silos clear of houses, overhead powerlines, animals, children, and water holes
- follow the manufacturer’s instructions exactly for preparation of the concrete slab
- provide a simple roof platform and ladder cages
- provide a wire mesh guard, which is hinged permanently on all external openings above the maximum grain level
- install ladders inside the silo as a way of emergency exit
- consult an engineer before modifying a silo; a simple change can impact its structural stability
- ensure warning signs around the silo are in good condition and list the hazards (including phosphine gas)
- secure silos to prevent unauthorised access (have ladders on the side start at 2 meters off the ground, and don’t store portable ladders in the area)
- enclose ladders in a safety cage and use fall protection systems when free climbing
- ensure all entry points remain locked and keys are held in a safe place under the supervision of a responsible person.
Working with silos
- take care when a new product is stored; every product has different characteristics and a silo designed to store one product may not be suitable for another
- use a ‘bedding-in’ procedure when filling by drawing off a rubbish bin full of grain
- keep people well clear when filling or emptying the silo, especially children.
Entering silos and other similar confined spaces
- ensure all adequate safety checks have been completed prior to issuing the worker a confined space permit to enter
- do not enter if fumigation is underway
- ventilate the silo before entry and never enter while it is being emptied
- never assume a silo has been emptied; hundreds of tonnes of material can remain on the sides
- turnoff and isolate the auger and power switch before entry so that the auger cannot be accidentally switched on while a worker is inside
- place a stand-by person outside the silo to talk to anyone in the silo and to implement emergency procedures, if needed
- have a rescue plan, emergency equipment, and crews available to help, if needed
- stay above the level of any jams while material is dislodged
- always wear a safety belt and harness if there is a danger of falling
- wear respiratory protection to reduce dust and mould exposure
- always wear an air-supplying respirator and running the blowers at maximum power if silo entry is required within four-to-six weeks of filling
- be aware that symptoms such as coughing, shortness of breath, and tightness in the chest could mean exposure to nitrogen dioxide and carbon dioxide
If entrapment occurs
- don’t panic or the grain will pack tighter; shield your face and chest with arms and clothing to create space for breathing
- empty the bin as quickly as possible by opening any side outlet then cut flaps in the cone or walls all around the base using power tools
- access to tools, breathing equipment, communications, and first aid in an emergency is part of the emergency planning and training procedures
Working with machinery
- lower mobile augers when transporting
- put mobile augers on firm, preferably flat ground, and operate at shallow (less than 45°) angles to prevent them from overbalancing
- regularly inspect and maintain augers and other machinery to ensure they are in good working order
- check that machinery guards are in place around moving parts (belts, pulleys, drive shafts) to prevent nip, pinch, and crush injuries.
You should regularly review your control measures. Don’t wait for something to go wrong. If necessary, change or adjust your approach. The aim is to maintain a work environment that is without risks to health and safety.
Work health and safety laws require you to review controls:
- when you become aware a control measure is not working effectively
- before a change that might introduce a new risk
- when you find a new hazard or risk
- when your workers tell you that a review is needed
- after a health and safety representative requests a review.
Standards and compliance
- Work Health and Safety Act 2011
- Work Health and Safety Regulation 2011
- Part 4.3 – Confined spaces of the Work Health and Safety Regulation 2011
- Australian Standard AS 1319 Safety signs for the occupational environment
Codes of practice
- How to manage work health and safety risks code of practice 2021 (PDF, 0.65 MB)
- Section 8 Part G of the Rural Plant Code of Practice 2004 (PDF, 0.63 MB)