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High pressure water blaster used on asbestos roof

In June 2019, two people used a high-pressure water blaster on a corrugated asbestos cement roof (super six roof). As a result, asbestos contaminated dust and debris (ACD) ended up on neighbouring residential properties.

Workplace Health and Safety Queensland (WHSQ) took immediate compliance action against the contractor to remediate the site at a cost of $13,000.

Investigations are continuing.

Preventing a similar incident

Queensland laws prohibit the use of certain tools and work methods when working with asbestos-containing materials (ACM) as they can generate dangerous airborne asbestos fibres. A person conducting a business or undertaking (PCBU) has a duty to ensure that workers and others are not exposed to the risk of airborne asbestos.

A PCBU must not use, direct, or allow a worker to use high pressure spray on asbestos or ACM. When working on buildings constructed before 1990, it is likely asbestos will be present in roofing and other sheet materials.

The person with management or control of the workplace (PMCW) must ensure, so far as is reasonably practicable, that all asbestos or ACM at the workplace is identified by a competent person. If the PMCW cannot identify ACM, but a competent person reasonably believes materials may contain asbestos, then the PMCW must assume asbestos is present.

Risk management must be completed and safe systems of work in place before starting work with any ACM. A PCBU must manage the risks associated with asbestos-related work, both to themselves and others. Cleaning an asbestos cement sheeting roof (super six) with a high-pressure water spray can destroy the roof surface, causingwidespread contamination throughout neighbouring properties. Effective risk management starts with a commitment to health and safety from those who operate and manage the business or undertaking.

Managing work health and safety risks is an ongoing process. Risk management involves four steps;

  • identify hazards - find out what could cause harm
  • assess risks - understand the possible harm, how serious it could be, and the likelihood of it happening
  • control risks - implement the most effective control measure that is reasonably practicable in the circumstances
  • review control measures - to ensure they are working as planned.

Managing the risks associated with asbestos involves:

  • identifying asbestos and ACM at the site
  • assessing the risk of exposure to airborne asbestos
  • eliminating or minimising the risks by implementing suitable control measures
  • reviewing control measures to ensure they are effective.

Once the risks have been assessed, the next step is to control risks for cleaning an asbestos roof. These control measures are ranked from the highest level of protection and reliability to the lowest and are known as the hierarchy of control. PCBUs must work through this hierarchy to choose the control that most effectively eliminates or, where that is not reasonably practicable, minimises risks.

The hierarchy of control measures are as follows:

  • Elimination - the most effective control measure is to remove the hazard or hazardous work practice associated with asbestos roofs by never using a high-pressure water spray or any other powered equipment to clean an asbestos roof.
  • Substitution - substitute the hazard with something safer. For example, replacing the ACM materials or roof sheeting following the How to Safely Remove Asbestos Code of Practice 2011.
  • Engineering - encapsulation or sealing the asbestos is the next appropriate control. For example, using a chemical fungicide, sealant, and then acrylic roof paint.
  • Administrative - administrative controls include systems of work or work procedures that are designed to eliminate or minimise risk and rely on human behaviour to be effective. Administrative control measures must be understood, implemented and maintained requiring requires training, information and supervision for workers.
  • Personal protective equipment (PPE) - PPE will need to be used, in combination with other effective control measures, when working with asbestos. The selection and use of PPE should be based on a risk assessment.

It is essential workers know how to identify and work safely with asbestos. A PCBU must provide information, training, instruction or supervision to protect all persons from risks to their health and safety associated with asbestos.


From July 2013 to September 2019, there were 34 events involving high pressure cleaning of asbestos containing materials. Most of these involved a PCBU cleaning an asbestos roof on a home before painting.

During the same period, WHSQ issued 12 improvement notices, 17 prohibition notices and 10 infringement notices (on the spot fines) specifically relating to cleaning asbestos containing materials with high pressure equipment.

Prosecutions and compliance

In 2018, a sole trader was fined $1,000 with a good behaviour bond for a period of 12 months with recognisance of $1,000 after an asbestos containing material ('ACM') roof was sprayed with a hydrochloride solution and a 'whirl-a-way' surface cleaner attached to a high-pressure washer. The sole trader was contracted to clean the roof of a residential premises by a painting company prior to painting. As a result, three adjacent residential properties were contaminated with a slurry of ACM. The person who sub-contracted the work was also prosecuted in relation to the incident, with the Magistrate commenting the person in control of the business holds responsibilities to ensure the work was completed safely. They also received a $1,000 fine.

In July 2017, a sole trader was fined $750 with a good behaviour bond for a period of 12 months with recognisance of $1,000 after a worker used a high-pressure water spray on a super six type asbestos roof. The sole trader was contracted to clean and paint a house with a super six type asbestos roof. He instructed his apprentice to get on the roof and use a high pressure water blaster. Asbestos contaminated dust or debris (ACD) scattered across the yard, as well as two neighbouring properties. In addition to penalties imposed by the court, the defendant also faced clean-up costs in excess of $18,000.

In 2014, two separate sole traders were fined $750 each with good behaviour bonds for a period of 12 months with recognisance of $1,000 after using high-pressure water spray on asbestos containing roofs. In addition to penalties imposed by the court, the sole traders also faced clean-up costs of $50,000 and $35,000.

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