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Two workers injured in fire and explosion at boatyard

In a recent incident, two workers suffered serious burns as a result of an explosion and fire at a marine facility. Initial enquiries indicate both workers were installing inboard marine engines into the floor of a boat located on a hardstand at the time. At some point during the installation process, the workers undertook testing of the engines using an auxiliary fuel tank as it appears the main petrol tanks were disconnected.

At some point during the testing process, for reasons yet to be established, an explosion and fire occurred resulting in serious burns to both workers.

Investigations are continuing.

Safety issues

Fire and explosion can result in catastrophic consequences, causing serious injuries or death of workers and others, as well as significant damage to property. There is real danger, when the following elements come together (commonly referred to as the fire triangle):

  • fuel (a flammable or combustible substance)
  • oxygen (usually in the air)
  • ignition (a source of energy sufficient to cause ignition).

Flammable liquids, including petrol, ethanol, enamel paints and thinners, and various solvents, give off hazardous vapours which can ignite if they build-up to their flammable range and come in contact with an ignition source. The risk of these vapours igniting is further increased when working in a confined space, an enclosed area, in a pit, or any other area where natural ventilation is restricted. The hull of a boat is an example of an area where vapours can be trapped and accumulate (concentrate or build up).

Ignition sources can be any energy source that has the potential to ignite a fuel. They can be categorised into four broad types: flames, arcs, sparks and heat. Examples of ignition sources include but are not limited to:

  • naked flames, smoking, pilot lights
  • portable electrical equipment such as power tools, radios, and fans
  • operating equipment with combustion engines such as forklift trucks, generators, compressors
  • hot surfaces, exhaust pipes, hot flues and ducts and frictional heating.

Ways to manage health and safety

Effective risk management starts with a commitment to health and safety from those who manage the business. If an incident occurs, you'll need to show the regulator that you’ve used an effective risk management process. This responsibility is covered by your primary duty of care in the Work Health and Safety Act 2011.

Use the hierarchy of controls to help decide how to eliminate and reduce risks in your place of work. The hierarchy of controls ranks types of control methods from the highest level of protection and reliability to the lowest. It’s a step-by-step approach to eliminating or reducing risks. You must work through the hierarchy of controls when managing risks, with the aim of eliminating the hazard, which is the most effective control.

Possible control measures to prevent similar incidents

A person conducting a business or undertaking (PCBU) must manage the risk to health and safety associated with a hazardous atmosphere or an ignition source in a hazardous atmosphere at the workplace. The Work Health and Safety Regulation 2011 (WHS Regulation) requires specific controls for fire and explosion prevention associated with hazardous chemicals.

Working on a petrol engine and/or fuel tank system can cause the release of flammable vapours. Petrol vapours are heavier than air which means they can sink into pits, sumps and depressions. The release of petrol vapours into the hull of a boat can be especially hazardous as the vapours can accumulate and linger in areas of restricted ventilation. Controls are required to manage this risk.

The highest level of protection is to eliminate, so far as is reasonably practicable, petrol vapours from being released into the work environment (atmosphere), i.e. stop an ignitable mixture of petrol vapours and air from forming. Sealing off disconnected fuel lines and removing all portable fuel tanks are example techniques.

When eliminating the release of petrol vapours is not possible, controls are required to reduce the likelihood of these vapours from:

  1. building up (concentrating) to an ignitable range (i.e. exceeding petrol’s lower explosive limit, LEL), and
  2. coming in contact with an ignition source.

Careful inspection is required to identify possible sources of petrol leaks and vapour releases when working on a boat’s fuel system. Petrol vapours can be released from vent caps and fill points when fuel tanks are being filled. A more subtle hazard is vent caps can release vapours when tanks are heated by the sun. And any fuel tank that has contained petrol, even if nominally empty, must still be treated as flammable as it only takes a few millilitres of petrol to form an ignitable mixture of fuel and air inside a recreational boat’s fuel tank.

An atmosphere (work environment) with a concentration of petrol vapours exceeding 5% of its LEL is defined as a hazardous atmosphere1 under section 51 of the WHS Regulation. Section 52 of the WHS Regulation requires PCBUs to carefully monitor and control the entry of ignition sources within a hazardous atmosphere. To avoid fires and explosions, such controls must prevent ignition sources from being present anytime a hazardous atmosphere contains a concentration of petrol vapour at or above its LEL.

The LEL for petrol can be identified in section 9 of the fuel product’s safety data sheet (SDS). The LEL is reported as approximately 1.4% by volume in air. The upper explosive limit is reported as approximately 7.6% by volume in air. Always check the manufacturer’s SDS for product-specific health and safety information.

A safety factor is recommended when monitoring LELs. SDSs for flammable liquids recommend all ignition sources be eliminated from any hazardous atmosphere. They may include advice to verify adequate ventilation using flammable vapour concentration limits (for example, not exceeding 25% of the LEL). Working around a hazardous atmosphere from petrol vapours must also be supervised by a competent person as per section 379 of the WHS Regulation.

  1. Flammable gas detectors allow for monitoring of flammable vapour concentrations in air and assist in managing hazardous (flammable) atmospheres. When incorporating gas detectors in safe work procedures, always ensure their function and use is well understood and in accordance with the manufacturer’s instructions. Ensure the user is competent in their use (e.g. understanding readings and alarm triggers, calibrations and any cross-sensitivities).

A safe system of work should be implemented to manage the fire and explosion risks associated with ignition sources and hot work activities. This safety alert does not include controls for managing hot work in-and-around a boat’s fuel system. Hot work includes work activities where ignition sources are inherent, and the temperatures involved can also cause combustible liquids like diesel and other non-flammable materials to be ignited. Work involving welding, grinding and drilling or using gas torches and naked flames etc. are examples of hot work.

Carrying out hot work on a boat with a petrol or diesel fuel system containing any quantity of fuel present is particularly hazardous and should be avoided, so far as is reasonably practicable. Where such hot work cannot be eliminated, risks must be minimised so far as is reasonably practicable. A risk assessment and hot work permitting system is recommended and the activity must be supervised by a competent person as per section 379 of the WHS Regulation. More advice on managing hot work can be found in AS 1674.1 Safety in welding and allied processes Part 1: Fire precautions.

1The definition of a hazardous atmosphere includes other flammable materials at concentrations exceeding 5% of their LEL.

Safe system of work

  • A safe system of work should be implemented to manage the fire and explosion risks associated with ignition sources and processes that generates heat. Obtaining the current safety data sheet (SDS) from the manufacturer, importer or supplier of the chemical and making the SDS readily available to workers.
  • Ensuring you keep a hazardous chemicals register for use by workers. A hazardous chemicals register is a list of hazardous chemicals stored, handled or used at a workplace (subject to any exclusions). The current SDS for each of the hazardous chemicals listed must be included with the register.
  • Ensuring ventilation is adequate to avoid the creation of a hazardous atmosphere. The aim of ventilation is to disperse flammable vapours and stop them from becoming ignitable.
  • Keeping and maintaining fire-fighting equipment nearby.
  • Providing workers – including experienced workers, with instruction, training, and supervision on the fire and explosion hazards, and safe work procedures. Training should be provided to workers by a competent person with information, training, and instruction provided in an easy-to-understand manner.
  • Ensuring worker training, experience, and competency aligns with the requirements and complexity of the task (workers must be trained and have the appropriate skills to carry out a particular task safely).
    • Keep records of training completed and ensure training is always fit-for-purpose. Some examples might include: How to work safely in hazardous environments, such as confined spaces, hazardous atmospheres, and hazardous areas.
    • How to access safety data sheets (SDS) for hazardous chemicals and be able to understand key information in the SDS and container labels, and
    • The proper use, storage, and maintenance of personal protective equipment (PPE).

Emergency plans

A PCBU must prepare an emergency plan to reduce the effects of an emergency involving hazardous chemicals at their place of work. When preparing an emergency plan, you must consider all relevant matters including:

  • the nature of the work being carried out at the workplace
  • the nature of the hazards at the workplace
  • the size and location of the workplace
  • the number and composition of the workers and other persons at the workplace.

A PCBU must also ensure the workplace is provided with fire protection and firefighting equipment that is designed and built for the types of hazardous chemicals at the workplace. The workplace should consider the hazardous chemicals from the perspectives of:

  • the quantities in which they are used, handled, generated or stored, and
  • the conditions under which they are used, handled, generated or stored, concerning:
    • the fire load of the hazardous chemicals
    • the fire load from other sources
    • the compatibility of the hazardous chemicals with other substances and mixtures at the workplace.

The control measures you put in place should be reviewed regularly to ensure they are effective.

More information

Support for people affected by a serious workplace incident

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