The fundamental approach to grain storage safety is the same as for all other farming activities. The aim is to have a safe workplace for everyone on the farm, including workers, contractors, families, visitors and the owner/managers.
- Safety is a three-step process — identify hazards, assess risk and address the hazard.
- Safe grain storage starts with well thought-out design and planning.
- Consider safety features when buying new storage.
- Using the correct storage for commodities such as granular fertiliser and high-moisture grain reduces the need enter the storage.
- Ventilate silos before entering and never enter a silo while it is being emptied.
- Use fumigants and chemicals carefully and follow the safety instructions on the label.
- Be aware of and comply with any worksafe and chemical use regulations in your state.
Start by identifying any hazards associated with the grain storage site. This involves talking with workers who use the site, taking time to thoroughly inspect the site and equipment and seeking advice and information from industry and Workplace health and safety (WHS) organisations to help identify risks that may not be initially apparent.
Secondly, assess the risk of each hazard in terms of its potential severity. If an accident occurred due to the identified hazard, would it result in scratches and bruises or is there potential for someone to be seriously injured or killed?
The third step is to address the hazard, starting with the highest-risk hazards first. The ultimate aim is to totally remove the risk, but where that’s not possible, find a way to control it. This could mean altering the way activities are carried out or providing protective equipment. After controlling the risk as much as possible, it is important to develop a plan of action in the event that an accident does occur. For example, if a worker is exposed to phosphine gas, or another harmful chemical, ensure emergency phone numbers are readily available to get medical help.
Designing a safe storage
Regardless of the type of grain storage used, selecting a suitable site is the first consideration when designing a safe grain storage system. If the storage site is already established, assess the site for following safety considerations and potential for improvement. If future expansion is being considered, it may be beneficial to build on a new site and decommission the current site when it reaches the end of its working life.
- Surroundings — locate the storage site away from overhead powerlines, houses where children might play, or houses or work areas that will be affected by dust and noise from grain storage activities.
- Access — ensure safe access for trucks turning into and out of the site from public roads without endangering other road users.
- Expansion — ensure the site is clear of trees, sheds and permanent structures to allow for expansion without having to manoeuvre trucks and augers in a cramped area.
- Drainage — select a relatively level site for easy and safe manoeuvring of augers and trucks, but ensure sufficient drainage is available to prevent having to work in wet, slippery and boggy conditions.
Smart storage selection
Choose storage that is cost effective and practical for the volume of grain to be stored. Considering safety in the mix makes for the ultimate storage result.
Sheds and bunkers are cost-efficient options for large quantities of grain, but require a considerable amount of manual labour and dedicated equipment to empty.
Silos are comparatively less labour intensive, although the amount of manual shovelling to completely empty silos is significantly reduced by choosing cone-bottom silos or flat-bottom silos with sweep augers.
Cone-bottom silos are the obvious choice for easy and safe out-loading. They are particularly beneficial if filled more than once a year — used as a buffer for harvest logistics.
Granular fertiliser, high-moisture grain and grain with a high percentage of screenings does not empty from standard silos very well, which commonly leads to people climbing into the silo to shovel out the stubborn grain. It is better to only store these types of commodities in silos with steeper cone bottoms or sheds where they can be out-loaded with a front-end loader.
Manufacturers are well placed to provide advice on choosing suitable storage types for various commodities.
Safety features on silos
Before buying a silo, consider the safety features on offer.
In most cases ladders are still required for monitoring grain in the top of the silo. State-based WHS requirements for ladders exist, but as a guide look for ladders with a safety cage and platforms every two metres, handrails on the top of the silo and a system that prevents children climbing the ladder.
Features that limit the need to climb the ladder are a valuable addition to silos and include:
- Sight glasses or a device to indicate the level of grain inside the silo.
- A system for applying fumigation at ground level, which will distribute the gas to the head space in the silo.
- Lids that can be opened and closed from the ground. (Be aware that few ground-operated lids can be closed and latched tight enough to be gas-tight for fumigation. Most lids still require a climb to the top of the silo to inspect rubber seals and latch the lid before the silo will meet a half-life pressure test, required for effective fumigation. When checking this point with manufacturers, refer to AS2628 — the Australian Standard for gas-tight silos.)
When working in a potentially dangerous environment, such as inside a silo, it is preferable to have another person outside to call if help is needed. Before entering the silo, ensure you are well hydrated and wearing suitable clothing to do the job (for example, sturdy, enclosed footwear). Avoid heat stress by carrying out the job during a cool time of the day so the internal silo temperature is more comfortable.
Before entering a silo:
- Open all lids and ventilation points well before entering to allow as much free-flowing air as possible. Damp grain, especially canola, will produce carbon dioxide and carbon monoxide at toxic levels. Monitors are available to test for these gases.
- Ensure all augers or conveyers filling or emptying the silo are stopped and cannot be started by someone else while you are in the silo.
- Stop and think if there is any way the job can be done from outside the silo.
- If entry is not through an access door at ground level, ensure the ladder has an appropriate safety cage. If not, a certified safety harness must be worn.
While working inside a silo:
- Have someone outside the silo to assist and get help if required.
- Wear an appropriate dust mask to prevent fine dust particles entering your lungs.
- Stay on the ladder above the level of compacted or bridged grain while dislodging it.
- If you become trapped under grain, avoid movement and don’t panic as this will worsen the problem — try to remain calm and call for help
Filling and emptying
Always fill and empty silos from the middle. Filling or emptying a silo from the sides will cause uneven loading on the silo, potentially causing a structural failure. Ensure augers and conveyors are fitted with adequate guarding.
Wear high-visibility clothing while working around moving machinery to reduce the chance of being run over. Ensure all workers are trained to safely operate the grain storage facilities, filling and emptying equipment and associated machinery.
Fatigue and stress are common during harvest; ensure all operators get enough rest or downtime to avoid fatigue and stress-related accidents.
Stored grain fumigants and chemicals
Even though alternative fumigants are becoming more readily available, phosphine is still widely relied upon to control pests in stored grain.
Phosphine is also one of the most dangerous products used on farm, which is why it is classed as a schedule seven poison, indicated on the label — DANGEROUS POISON.
As a minimum requirement, the label directs the use of cotton overalls buttoned to the neck and wrist, eye protection, elbow-length PVC gloves and a breathing respirator with a combined dust and gas cartridge.
Never rely on the odour of phosphine to determine if the atmosphere is safe. The odour threshold of phosphine (for those that can smell it) is 2 parts per million (ppm). The threshold limit value for a time weighted average is 0.3ppm and the short-term exposure limit is 1ppm. This means by the time workers can smell phosphine (2ppm) the gas concentration level is already exceeding the safe exposure limits.
Always read the product label and Material Safety Data Sheet (MSDS) for safety information and required personal protection equipment (PPE). The respirator must be fitted with a combined dust and gas cartridge (canister) with an international code that includes the letter ‘B’, which stands for inorganic gas. The number in the code refers to the capacity of the cartridge, for example an ABE1 has a shorter life span than an ABE2.
Personal phosphine monitors are available and easy to use. The monitors simply clip onto the operator’s collar or top pocket (close to their nose and mouth) and will sound an alarm if more than 0.3ppm is detected and sound another alarm if more than 0.6ppm is detected. Price may deter growers who only use phosphine occasionally, but these handy devices can potentially save a life, so are worth serious consideration.
Place a warning sign on the silo to tell others to stay away. The sign must contain the words DANGER — POISONOUS GAS, KEEP AWAY.
State Worksafe organisations and government WHS contacts
- Safe Work Australia
- WorkCover Authority of NSW
13 10 50
- WorkCover SA
1300 365 255
- Workplace Health and Safety QLD
1300 362 128
- WorkSafe Tasmania
1300 366 322
- NT WorkSafe
1800 019 115
- WorkSafe Victoria
1800 136 089
- WorkSafe WA
1300 30 78 77
- WorkSafe ACT
(02) 6207 3000