Worker burned following chemical explosion

In November 2021, a worker suffered burns to his shoulders, knees and face following an explosion at a marine maintenance facility.

Early enquires indicate he was doing fibreglass repair work inside the hull of a boat using acetone. It appears a nearby heat gun has potentially ignited vapours generated by the acetone resulting in an explosion.

Investigations are continuing.

IMPORTANT

These findings are not yet confirmed, and investigations are continuing into the exact cause.

Safety issues

Workers and others may suffer serious injury or even die as a result of fire and explosion, while there also likely 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 not properly managed. There’s an increased risk of these products igniting when working with them in a confined area. This is because vapours can be trapped and accumulate, forming a flammable or explosive concentration in air.

Ignition sources can be any energy source that has the potential to ignite a fuel. They can be categorised into three broad types: flames, 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
hot work activities such as welding, hot-cutting, grinding and heat treatment.

Ways to manage health and safety

Taking steps to manage risks is a condition of doing business in Queensland. 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 requires specific controls for prevention of fire and explosion risks associated with hazardous chemicals. These include:

s51 - A PCBU at a workplace must manage risks to health and safety associated with a hazardous atmosphere at the workplace and;
s52 - A PCBU at a workplace must manage risks to health and safety associated with an ignition source in a hazardous atmosphere at the workplace.

In relation to hazardous chemicals, a hazardous atmosphere is when the atmosphere has a concentration of flammable vapour that exceeds 5% of the lower flammable explosive limit (LEL) for the vapour. For example, acetone has a LEL of 2.6% by volume in air (refer to product’s Safety Data Sheet). With this product, a hazardous atmosphere is generated at 0.13% by volume in air (i.e., 5% of 2.6%).

Effective controls for fire and explosion risks are often made up of a combination of controls.

Elimination

Elimination is the most effective control measure and must always be considered before other control measures. For example:

you may choose to not use a hazardous chemical (for example using a water-based cleaner instead of flammable solvent based cleaner). This will eliminate the generation of flammable vapours.
eliminating potential ignition sources from the area.

If this is not reasonably practicable, the risk must be minimised by using one or more of the following control measures. Examples can include but are not limited to:

Substitution

Substituting a highly flammable product with a less-flammable product.

Engineering

Installing ventilation to avoid the creation of a hazardous atmosphere (an intrinsically safe exhaust fan with ducting to target the source of vapours, capture vapours and disperse these to a safe place). This is to avoid accumulation of vapours in an enclosed area. The aim of ventilation is to disperse flammable vapours and avoid creation of a hazardous atmosphere. It can be achieved using natural or mechanical ventilation systems.

Ventilation is a significant engineering control. Correct design is essential to ensure it is effective. There are a range of different ventilation systems, and the most appropriate form needs to be used. Ventilation systems should be suitable for the types of hazardous chemicals and the nature of the work.

Depending on the vapour density, vapours can flow across surfaces in a similar way to liquids, rather than dissipating quickly. Vapours from flammable liquids are heavier than air and under calm conditions will tend to sink and accumulate in low-lying areas. These heavier-than-air vapours can move along the floor and spread to adjacent work areas, or be trapped within an enclosed area like the interior of a boat. This spread and accumulation of vapours creates a significant fire risk in those areas when potential ignition sources are not managed.

To ensure the effectiveness of ventilation systems, they should be designed in accordance with appropriate technical standards, and installed and maintained by qualified or experienced persons, such as engineers or occupational hygienists. Regular checks of these systems (i.e. fixed and portable types) should be included in planned maintenance schedules to ensure that the type of ventilation is still fit for purpose and does cause escalation or production of risk.

Administration

Administration controls include developing a safe system of work to manage fire and explosion risks. Administrative controls should only be considered when other higher order control measures are not practicable, or to supplement other control measures.

This could include, but is not limited to the following examples:

Using portable and/or installing fixed systems to detect leaks of flammable gases or vapours ensuring their function and use is well understood and the user is competent in their use (e.g. understanding readings and alarm triggers).
Developing permit systems preventing hot work in areas where a hazardous atmosphere potentially exists. A hot work permit system is designed to control when and how hot work is undertaken. Further information on hot work permit systems is available in the following Australian Standards:
- AS 1940: The storage and handling of flammable and combustible liquids
- AS 2865: Confined spaces: Appendix F
- AS 1674.1: Safety in welding and allied processes—Fire precautions.
Ensuring containers of hazardous chemicals are used, handled and stored away from ignition sources (e.g. electrical or gas heating appliances).
Developing policies and safe work procedures for the use, handling, storage, clean up and disposal of hazardous chemicals.
Consulting with workers and others involved in the task to obtain feedback on processes and safe work procedures.
Developing a maintenance schedule for engineering control measures.
Providing workers with information, training and instruction on:
- the nature of the hazardous chemicals and the risks to workers while taking into account the health and safety information located within the product’s Safety Data Sheet (SDS)
- the availability of SDS for all hazardous chemicals, how to access the SDS, and the information that each part of the SDS provides
- arrangements to deal with emergencies, including evacuation procedures, containing and cleaning up spills and first aid instructions
- work practices and procedures to be followed in the use, handling, storage, cleaning up and disposal of hazardous chemicals.

The control measures you put in place should be reviewed regularly to make sure they work as planned.

More information

Support for people affected by a serious workplace incident

For advice and support: