Serious fire and explosion injuries in three hot work incidents

In October 2022, a worker suffered serious burns to his upper body after being engulfed by a fire at an engineering workplace. Early investigations revealed he was welding a metal plate to repair a leak to a tank, when an explosion occurred which resulted in a fire.

In a second incident in October, a worker suffered facial injuries when the lid of a 44-gallon drum struck him. Initial investigations demonstrated he was preparing to remove the drum lid with a range of cutting tools, when an explosion occurred. The majority of the lid separated from the drum causing him injury.

A third fire and explosion incident also occurred in October, which resulted in one worker receiving fatal burns and two other workers sustaining serious burns. Initial enquiries indicated one worker was using an electric grinder at the time to cut a drum.

IMPORTANT

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

Safety issues

'Hot work' is any process involving grinding, welding, brazing, oxycutting, heat treatment or any other similar process that generates heat or continuous streams of sparks. Undertaking hot work in areas where flammable or combustible chemicals or materials are present, could create a significant risk of fire or explosion.

Conducting hot work on containers such as drums, tanks and pipes that have not been properly decontaminated is a common cause of serious incidents. Even if a drum or container is considered to be empty, and has been empty for a long time, flammable vapours can still remain and be a risk of explosion when heat is applied. Simply rinsing drums or containers is not a fail-safe way to remove oily residues or flammable vapours.

Very small quantities of flammable or combustible substances (including diesel and oils) within a closed drum or fuel tank on which hot work is conducted can have catastrophic impacts. Incidents have occurred where bungs are left in steel drums and containers are sealed/closed off effectively creating a bomb. Heated residues expand and can pressurise the container to the point of failure leading to a significant release of energy that can cause harm to people and property.

Containers of concern are not just fuel containers. Some chemical formulations such as agricultural chemicals may also include flammable or combustible solvents presenting similar fire or explosion risks with their containers.

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

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

If there is a possibility of fire or explosion in a hazardous area being caused by an ignition source, as a PCBU, you must ensure the ignition source is not introduced into the area. A PCBU must also manage risks to health and safety associated with a hazardous atmosphere. This includes identifying all sources of ignition, such as welding, hot-cutting, and grinding, which generate heat, flames and sparks, that could cause an ignition.

In relation to hazardous chemicals, a hazardous atmosphere is when the atmosphere has a concentration of flammable vapour that exceeds 5 per cent of the lower flammable explosive limit (LEL) for the vapour.

You must ensure that flammable or combustible substances in the workplace are kept in the lowest practicable quantities. This includes waste liquids in containers and gas cylinders, whether empty or full.

Effective controls for fire and explosion risks associated with hot work are often made up of a combination of controls including:

avoiding the reuse of fuel containers and ensuring they are properly disposed of, and
isolating fuel sources from ignition sources.

Safe system of work

A safe system of work should be implemented to manage the fire and explosion risks associated with ignition sources and hot work activities. This can include:

Having a hot work permit system designed to control when and how hot work is undertaken. More information on hot work permit systems is available in the following Australian Standards:
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 – the current SDS for each of the hazardous chemicals listed must be included with the register.
Checking what has previously been stored in the empty drum or container by reading the label and reviewing the SDS for the hazardous chemical and assessing the information provided on the safe storage and handling. If it has been found to contain flammable or combustible substances, seek to properly dispose of the container and avoid any hot work on it.
Be wary of any container that is not correctly labelled (e.g., label has been removed or has become illegible) or has an unknown history. The best approach is to properly dispose of such containers otherwise it will have to undergo appropriate cleaning and testing to verify that there is no fire or explosion risk resulting from historical contents.
If there is no alternative but to perform hot-work on the container, remove all traces of flammable or combustible materials from the container to ensure it is properly cleaned of residues and vapours and certified as vapour-free by a competent person noting that:
- unless containers have been cleaned out to be free of flammable and combustible substances, vapours can remain in containers for many years, and
- rinsing drums may not be enough to remove vapours from within a container
Using fire resistant barriers to prevent other non-related hot work (e.g. welding or grinding) sparks accidently reaching flammable and combustible materials including nominally empty containers.
Do not use drums as a welding or work platform.
Store empty drums with bungs removed in a well-ventilated place away from other work areas. Removing the bung will not guarantee all hazardous residues and vapours have been naturally vented. Note that flammable vapours from flammable liquids like petrol are heavier than air and will collect at the bottom of a container and can remain there for years until actively removed.
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 safely control any fire and explosion hazards if performing hot-work on containers that have contained chemicals.
- 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

Under the Work Health and Safety Regulation 2011, 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, a PCBU 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.

In Queensland, fire protection and firefighting equipment must be compatible with equipment used by the Queensland Fire and Rescue Service. It must be properly installed, tested, and maintained with a dated record kept of the latest testing results and maintenance until the next test is conducted.

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

For advice and support: