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Motor Vehicle Repair – Harmful Dusts Inhalation and Dermatitis risks

Exposure to dust from sanding vehicle body fillers can cause damage to the respiratory system and irritation to the skin that may lead to dermatitis or other skin conditions. Dust can irritate and damage the eye. Appropriate control measures are required to manage the inhalation and dermatitis risk.


Most vehicle body fillers consist of thermosetting unsaturated polyester in a solvent which is mixed with a reactive hardener. Hardeners are usually skin irritants and some are strong skin sensitisers. Both the filler and hardnerer can cause dermatitis. Styrene and methacrylates are often found in these mixtures and have powerful odours. Both styrene and methacrylates can affect the nervous system.

Check the safety data sheet for these chemicals and if you find them, try to find alternative less harmful filler products. Glass fibre fillers can irritate the skin.

To minimise the number of people exposed to dust and vapours, separate the body filling and preparation area away from other work.

When using powered sanding tools and sander with built in extraction should be used. Portable local exhaust ventilation may be appropriate, positioning the local extraction close to the work is necessary.

Where it is necessary to remove large excesses of filler the use of large coarse hand files should be considered

Even if the dust does not contain specific harmful substances (such as styrene or methacrylates) you should keep dust to a minimum as the quantity generated can be damaging to health.

Where necessary, personal protective equipment such as disposable overalls should be sued to help prevent dust build up on clothing. Suitable gloves (eg nitrile gloves) should also be considered as fine dust will clog up the pores in the skin and they would also protect the hands when wet sanding.

In some situations respiratory protective equipment may be required, a P2 dust mask is usually adequate.

For information on air monitoring and exposure assessment click here.

For further information on how we can assist you with noise assessment services call our office or use our contacts page to forward a request for further information.

Sunshine Coast, Brisbane, Gold Coast and Regional Queensland

Workplace Noise Exposure and the Queensland Noise Legislation

Workplace noise-induced hearing loss is still a major compensable disease in Queensland workplaces. Noise-induced hearing loss is caused by excessive noise in the workplace. A worker may have an entitlement to compensation for hearing loss if their employment was a significant contributing factor causing the loss of hearing.

The Queensland Work Health and Safety Act 2011 places responsibility for managing workers health and safety risk on the ‘persons conducting a business or undertaking’ (PCBU). The WHS Regulations 2011 detail responsibilities for the PCBU to ensure noise exposure does not exceed the exposure standard and to provide hearing tests for certain workers.

In Queensland noise is prescribed in Part 4.1 of the Work Health and Safety Regulation 2011.  For this standard excessive noise is a level of noise above an 8-hour equivalent continuous A-weighted sound pressure level (LAeq,8h) of 85dB(A) and a C-weighted peak sound pressure level exceeding 140 dB(C). The LAeq,8h represents a steady noise which, if averaged over 8 hours, equates to a daily noise exposure.

It is important to understand that this standard should not be considered a safe exposure level, where over a period of time there would be no damage to someone’s hearing or potential for other health effects. Rather, the standard of 85 dB (A) is considered to be an ‘acceptable’ risk for the working population.

For instance, research indicates that after an exposure to 85 dB (A) over a 40 year working life, 74% of exposed males can expect to experience a 6% hearing disability while 47% of females can expect to experience a 6% hearing disability.

The implication for the workers is that, even with the current noise exposure standard, a large percentage of the workforce can expect to have incurred significant hearing loss by the time they cease working. Therefore, it is imperative that noise exposure is kept below the exposure standard.

The Managing Noise and Preventing Hearing Loss at Work Code of Practice 2011 prescribe ways of preventing or minimising risks to workers from exposure to excessive noise at a workplace.

Effective noise management requires assessment of noise levels and workers exposure, engineering noise control, personal protective equipment, audiometric testing (hearing tests) and worker training.

A noise assessment may be required to quantify the noise exposure risk to workers. Workplace Noise Assessments should be conducted by a competent person (occupational hygienist) to meet the requirements of AS1269.1: 2005 Measurements and Assessment of Noise Immission and Exposure. .

In most situations the noise assessment involves a combination of personal exposure measurements and noise level measurements for plant and equipment. Where required noise contour maps can be developed.

The period between noise assessments should be determined by management in consultation with workers through consultative processes. The noise assessment should be repeated at intervals not exceeding five years or whenever there is a significant change to the conditions that affect exposure.

For information on workplace noise monitoring click here.

For information on plant noise assessments click here.

For further information on how we can assist you with noise assessment services call our office or use our contacts page to forward a request for further information.

Sunshine Coast, Brisbane, Gold Coast and Regional Queensland

Vehicle paint sprayers are 80 times more likely to get asthma than the average worker. 1 in 10 of workers in bodyshops who get asthma from isocyanates are not sprayers.

Myth 1: “We use water-based /UV-cured paints, which are isocyanate-free. Anyway, isocyanates are going to be banned”

Truth 1: Almost all bodyshops use isocyanate-containing paints. Rumours that isocyanate-containing paints will be banned are incorrect. Isocyanates will continue to be used in some primers and base coats as well as UV-cured coatings and some water-based paints.

Remember, ‘Water-based’ does not mean ‘isocyanate-free’. And almost all top coats contain isocyanates.

Myth 2: “Modern guns don’t mist like the old ones so are much safer”

Truth 2: All modern guns are designed to produce less mist. But that assumes that they are set up as the manufacturer intended – and that still doesn’t make them safe. Modern guns still produces average levels of isocyanate over 1000 ug/m3 (over 50 times the workplace exposure value, which itself is not a safe value).

Myth 3: “It won’t affect me, I wear a mask”

Truth 3: Wearing a respirator is essential when using isocyanate-containing paints but you need to ensure:

It is the right type – only air-fed breathing apparatus is suitable for isocyanate spraying (filtering face masks are not acceptable); and

It is used at all times when exposure is possible – many sprayers believe it is safe to remove their mask as soon as they have finished spraying but the air still contains large quantities of paint mist that is invisible to the naked eye.

Myth 4: “I work in a booth so the air is kept clear”

Truth 4: If you work in a modern purpose built spray booth with large quantities of filtered air flowing past it is easy to believe that all the overspray is instantly carried away leaving the air safe to breath as soon as spraying is finished. This is a dangerous misconception. In fact, spray booths typically take between one to five minutes to clear. During this time, it is essential that you keep wearing your air-fed mask and no unprotected person enters the booth.

Spray rooms are much cruder devices than booths and are much slower to clear (it can take half an hour or more). The levels of isocyanate in spray spaces have been measured at levels up to 300 times the workplace exposure limit. If you want to carry on using a spray room you need to make sure it works as safely and efficiently as possible.

Anyone using a spray booth or room needs to know what the clearance time is. Booths and spray rooms only work effectively if they are kept maintained.

Myth 5: “I can go in the booth/spray room as soon as the mist has cleared”

Truth 5: One in 10 of people who get asthma from isocyanates in bodyshops are not sprayers. This means they are getting exposed some other way. One of those ways is entering a spraybooth/spray room before the entire fine, invisible mist has cleared. Even the most efficient booths take over a minute to clear after spraying has finished. Some take significantly longer. A spray room can take up to half an hour to clear.

Anyone entering a spray booth or spray room needs to know what the clearance time.

Myth 6: “It’s only a touch-up job, I can do that in the workshop”

Truth 6: One in 10 of people who get asthma from isocyanates in bodyshops are not sprayers. This means they are getting exposed some other way. One of those ways is by people spraying outside the spray booth. Perhaps it is because the job is short or the booth is already in use. But the fact is that large quantities of paint mist are spread throughout the workshop endangering the health of anyone in the vicinity

Myth 7: “Isocyanates cause cancer but so does everything else these days.”

Truth 7: There is no known case of isocyanate used in paints causing cancer! But they are the biggest cause of occupational asthma in Australia. To confuse the two may cause someone to overlook the classic early symptoms of asthma – wheezing, breathlessness and tightness of the chest. This means they don’t seek medical attention and the problems at work that are leading to exposure aren’t put right because they are unlikely to link their symptoms to work.

Myth 8: “Asthma isn’t serious – most kids have got it these days”

Truth 8: Asthma is a life threatening and life-changing condition. If you get asthma from isocyanates, you can never work with or near isocyanate products again, which probably means losing your job. Your lungs are damaged permanently

Myth 9:”The biggest problem is absorption through the skin but I wear gloves and an overall”

Truth 9: Many sprayers believe that a significant or even the main route of entry for isocyanate paint spray is through the skin with the “thin skin around the eyes” being a particular concern. These views are confusing and wrong. The overwhelming route of entry for isocyanate paint mist in MVR bodyshops is through inhalation of fine airborne paint mist and this is what puts sprayers at risk of getting occupational asthma. Getting mixed 2-pack isocyanate paint or liquid hardener drips/splashes on the hands/skin can cause dermatitis but that is a different issue.

Myth 10: “I’ve got nothing to worry about, I’ve had my yearly check-up and it’s all clear”

Truth 10: Asthma is a very variable condition. One day you may feel fine and the next you cannot breathe so, just because you showed up clear on the day of your breathing test doesn’t mean you should ignore other symptoms. If you experience problems such as wheezing, breathlessness or tightness of the chest (which may occur some hours after exposure), make sure you report them to your GP, explaining that you work with isocyanates. A urine test (in addition to the annual ones you should be giving) should show up any exposure to isocyanate.

For information on air monitoring click here.

For information on health risk assessments click here.

For further information on how we can assist you with air monitoring services call our office or use our contacts page to forward a request for further information.

Sunshine Coast, Brisbane, Gold Coast and Regional Queensland

Testing of Air Quality for Supplied Air Respirators / Compressor Air Quality Testing

Contamination in compressor supplied air can be a serious health risk. Testing of Air quality for supplied air respirators provide confidence to the workers required to use supplied air respirators.

Testing Requirements for Air Quality Supplied Air Respirators

The compressor breathing air quality requirement for supplied air respirators is often one of the least understood elements of a respiratory protection program.

Workplace Health and Safety Law requires that breathing air meet specified requirements and be tested to an agreed schedule as detailed in Australian Standard 1715:2009, Selection, Use and Maintenance of Respiratory Equipment. Checks are required to identify that there are no contaminates in the supplied air and that sufficient air is provided to the user

As part of the respirator protection program for a compressor air supply system, it is necessary to check the quality of the air regularly. Air quality checks should be conducted to an appropriate schedule. In many situations annual checks are sufficient to show if there is any deterioration in the system. The frequency of testing should be reviewed dependant on the usage and results of the testing.

Method for Testing Air Quality Supplied Air Respirators

Onsite testing is conducted by our technicians using use the Dräger Breathing Air Test Kit Method, Aerotest Simultan to determine the concentration of oil, water vapour, carbon monoxide (CO), and carbon dioxide (CO2) contained in the breathing air that is delivered to workers. Real-time monitoring equipment is used to determine the oxygen content. The capability of the compressor is assessed and a determination made on its ability to supply sufficient air to each person using a respirator connected to the system.

Air Quality for Supplied Air Respirators Parameters

The parameters for the air quality for supplied air respirators are detailed below.

Component Analysed


Capacity >  170 L/min for each person
Oxygen 19.5% to 22%
Carbon Monoxide < 11mg/m3 (10ppm)
Carbon Dioxide < 1400 mg/m3 (800 ppm)
Oil < 1mg/m3
*Water < 100 mg/m3
Air Temperature 15°C to 25°C
Odour Not Objectionable

* Cylinder initially filled to pressure of at least 12 MPa.

The specification for water content does not specifically apply to low pressure breathing air supply systems, however high water content can lead to contamination of the supply lines and associated contamination of the breathing air.

Trained Technicians Air Quality Supplied Air Respirators

All testing is conducted by trained technicians using accredited state-of-the-art sampling and analysis methodologies. Testing can be conducted for industrial breathing air systems such as air hoods used for spray painting, and airline systems used in confined spaces, welding and chemical applications.

Our technicians can assist resolve any issues that are identified and will issue certification for the system once testing shows that the legislative requirements for breathing air quality have been met.

Download a generic Air Quality Supplied Air Respirator Certificate.

For detailed advice on assessment and specific control measures for your workplace contact our consultants.

For further information on testing air quality for supplied air respirators click here.

Haztek: Servicing Sunshine Coast, Brisbane, Gold Coast and Regional Queensland

Indoor Air Quality Dampness and Mould

Problems of indoor air quality are recognised as important risk factors for human health. Knowledge of indoor air quality, its health significance and the factors that cause poor quality are key to enabling action by building owners, users and occupants, to maintain clean indoor air.

Following significant rain events there may be significant ingress of moisture to buildings. Excess moisture on almost all indoor materials leads to growth of microbes, such as mould, fungi and bacteria, which subsequently emit spores, cells, fragments and volatile organic compounds into indoor air. Furthermore, dampness initiates chemical or biological degradation of materials, which also pollutes indoor air.

Indoor Air Quality Mould Health Effects

The most important health effects of mould exposure are increased prevalence of respiratory symptoms, allergies, asthma and immunological reactions. Exposure to mould and other dampness-related microbial agents increases the risks of rare conditions, such as hypersensitivity pneumonitis, allergic alveolitis, chronic rhinosinusitis and allergic fungal sinusitis.

While groups such as atopic and allergic people are particularly susceptible to biological and chemical agents in damp indoor environments, adverse health effects have also been found in non-atopic populations.

Health hazards result from a complex chain of events that link penetration of water indoors and excessive moisture to biological growth, physical and chemical degradation, and emission of hazardous biological and chemical agents.

The presence of many biological agents in the indoor environment is due to dampness and inadequate ventilation. Excess moisture on almost all indoor materials leads to growth of microbes, such as mould, fungi and bacteria, which subsequently emit spores, cells, fragments and volatile organic compounds into indoor air.

Dampness as an Indicator of Indoor Air Quality for Mould

Dampness is strong, consistent indicator of the risk of asthma and respiratory symptoms (e.g. cough and wheeze).  The health risks of biological contaminants of indoor air can thus be addressed by considering dampness as the risk indicator. Assessment of parameters such as relative humidity and ventilation rates are effective indicators of a mould exposure risk.

Indicators of dampness and microbial growth include the presence of condensation on surfaces or in structures, visible mould, perceived mouldy odour and a history of water damage, leakage or penetration. Thorough inspection and appropriate measurements, if necessary, can be used to confirm indoor moisture and microbial growth. The most important means for avoiding adverse health effects is the prevention (or minimisation) of persistent dampness and microbial growth on interior surfaces and in building structures.

Assessment of Mould Indoor Air Quality

A visual inspection of the building can identify evidence of mould on building structures including carpet and floor areas.

High relative humidity, dampness and a strong musty smell are strong indicators of mould.

Monitoring for Carbon Monoxide, Carbon Dioxide, Oxygen, Air Temperature, Relative Humidity and Ventilation rates provides useful information for assessing indoor air quality. Monitoring for Particulates, Formaldehyde and Volatile Organic Compounds can also be useful in specific situations.

In some situation conducting air monitoring for mould could be considered. In most cases air monitoring for mould is not recommended. To get effective data from air monitoring for mould it is necessary to monitor over an extended period and collect a lot of samples. The World Health Organisation recommends a minimum of 27 samples to get statistically relevant data.

The Australian Government Guideline for Air conditioning and thermal comfort states ‘The consensus view of health authorities appears to be that the setting of quantitative standards for the microbiological contamination of air in office buildings is not particularly useful, and that measurement of the microbial content of the air in office workplaces is rarely helpful’.

Various commercial organisations (particularly those marketing testing and decontamination services) and others have proposed their own guideline values for the evaluation of microbial test results. The guidelines mostly lie in the 500 to 5000 CFU/M3 range, however they appear to have little basis other than undocumented claims of experience and should not be followed unless supported by sound scientific justification and approved by the relevant Health Authority.

Control of Indoor Air Quality Mould

Apart from its entry during occasional events (such as water leaks, heavy rain and flooding), most moisture enters a building in incoming air, including that infiltrating through the building envelope or that resulting from the occupants’ activities.

Well-designed, well-constructed, well-maintained building envelopes are critical to the prevention and control of excess moisture and microbial growth, as they prevent thermal bridges and the entry of liquid or vapour-phase water. Management of moisture requires proper control of temperatures and ventilation to avoid excess humidity, condensation on surfaces and excess moisture in materials. Ventilation should be distributed effectively throughout spaces, and stagnant air zones should be avoided.

Building owners are responsible for providing a healthy workplace environment free of excess moisture and mould, by ensuring proper building construction and maintenance. The occupants are responsible for managing the use of water, heating, ventilation and appliances in a manner that does not lead to dampness and mould growth.

For detailed advice on assessment and specific control measures for your workplace contact our consultants.

For further information on indoor air quality click here.

Haztek: Servicing Sunshine Coast, Brisbane, Gold Coast and Regional Queensland

Useful references

Air-Conditioning and thermal comfort in Australian Public Service offices, Comcare Australia 1995.

HVAC Systems and Equipment. ASHRAE Handbook ASHRAE Atlanta 2000.

World Health Organisation (WHO) Guidelines For Indoor Air Quality Dampness And Mould, 2009.

Planning the Asbestos Survey

At the onset the goals of the asbestos survey should be outlined. The primary gaol of the survey is to develop an asbestos register and prepare an asbestos management plan. These tools can then be used to determine management actions to control the health risk of asbestos exposure. At this stage the data required from the survey and information required to conduct the survey should be outlined. A detailed list of information that may be required is provided in the document UK HSE Asbestos: The Survey Guide. Consideration of all the available information is required to develop the survey plan. Long term management options should be discussed and the decision making stages of the survey determined.

A risk assessment of the survey should be conducted at this stage, it is likely that the risk assessment will require review following the initial site inspection.

Competent Person for Asbestos Survey

The Qld WHS Regulations 2011 ‘require a person with management or control of a workplace to ensure asbestos or ACM at the workplace is identified by a competent person’. Skilled and qualified persons may be available within the organisation or consultants may be contracted for the work. The person responsible for managing the project should ensure that the requirements of the Qld How to Manage and Control Asbestos in the Workplace Code of Practice 2011 are met for a competent person. References from previous projects and qualifications, licences and relevant experience should be checked.

Due to the sensitive nature and potential concerns for workers and customers it is important to ensure that the person conducting the survey has a good understanding of the health risk and other commercial risks and that clear paths of communication are maintained between all stakeholders.

Initial Asbestos Survey

There may be information available detailing the location of ACM within the premises. The first step is to collect and review all available information.  This involves a review of available information on materials within the premises that may contain asbestos. If the location of asbestos is known it is important to know the condition of the material and whether any work had been conducted on ACM which may have damaged or disturbed the material.

A review of building designs and maintenance works including any modifications provides an insight to where ACM could be located and work that had been undertaken on the premises. As records often don’t accurately reflect the building design and conditions including any modifications a physical inspection of the premises is usually required.

At this stage it is appropriated to conduct an initial inspection to ascertain the presence of materials that could contain asbestos. Factors which should be considered at the stage include, date the building was constructed, any modification that have been done, materials used in construction, information from designers / manufactures or plant, information from facilities management personnel and identification of difficult or inaccessible areas.

If the review shows that there are no materials that could contain asbestos, such as the building is constructed of brick and steel, no further investigation may be necessary. The initial inspection would also allow the scope of further detailed inspections which may include sampling to be determined.

An advantage of conducting an initial inspection is the organisation the opportunity to immediately implement restrictions on work that may result in an unacceptable exposure to airborne asbestos fibres. Another advantage is that management could develop a clear understanding of the potential situations and plan and communicate in a manner that would not create unnecessary concern to employees or clients.

At the initial inspection management decisions on the control of asbestos can be made by presuming materials contain asbestos and taking actions to control the potential for disturbance of the materials. Due to the sensitive nature of asbestos, actions such as restricting work approvals or access to certain areas may be appropriate at this stage. Management actions at this stage are short term measures while further information is collected.

Identification Asbestos Survey

Based on the information collected in the initial assessment a more comprehensive assessment may be required. Consideration would be given to accessibility of areas including the risk of access and whether it is more feasible to assume the presence of asbestos. If another area is easily accessible and is confirmed ACM it may be more practical to assume all areas of similar materials are ACM. It is not acceptable to assume a material does not contain asbestos without comprehensive information such as bulk sampling.

Prior to taking bulk samples a risk assessment must be completed for the task, including; access risk such as working at height, electrical and confined space entry and asbestos exposure risk for taking the sample, transport of the sample and repair of any damaged material during sampling.

When determining whether to sample a number of issues must be considered. The Qld WHS Regulations 2011 required that asbestos material be identified as far as reasonably practical, however the Qld How to Manage and Control Asbestos in the Workplace Code of Practice 2011 provides guidance that ‘if asbestos is stable and non-friable and will not be disturbed, it should be left alone’.  There may be significant implications for management for asbestos, these implications should be considered when determining whether the risk of obtaining a sample outweighs the benefits of identification through sampling.

Specific requirements for analysis of samples are detailed in Qld How to Manage and Control Asbestos in the Workplace Code of Practice 2011. Analysis can only be conducted by a NATA-accredited laboratory or one that is approved by or operated by the relevant regulator.

Asbestos Risk Assessment

As previously stated the health risk of asbestos is from inhalation of fibres. An asbestos survey should assess the condition of asbestos materials and their ability to release fibres. Numerous risk assessment protocols are available such as those recommended in the Model WHS Regulations and AS/NZS ISO 31000:2009, Risk Management – Principles and guidelines. These risk management protocols are developed to assess the task. For asbestos in buildings it is useful to assess the ability to release fibres of the material. The UK Health Safety Executive: Asbestos – The survey guide HSE 2010 provides guidance on how to conduct a material risk assessment using algorithms. This tool allows for assessment of the potential for fibre release which can be used when determining management plans for specific areas.

The risk assessment protocol should be determined in consultation with the relevant stakeholders use of the UK HSE algorithms is recommended as a practical option.

A material assessment is conducted taking into account the following factors:

  • Product type;
  • Extent of damage or deterioration;
  • Surface treatment; and
  • Asbestos type.

The material assessment can be extended to a priority assessment to assist in developing the asbestos management plan by considering the following factors:

  • Location of the material;
  • Extent of the material;
  • Use to which the location is put;
  • Occupancy of the area;
  • Activities carried on in the area; and
  • Likelihood/frequency with which maintenance activities are likely to take place.


For detailed advice on assessment and specific control measures for your workplace contact our consultants.

For further information on asbestos click here.

Haztek: Servicing Sunshine Coast, Brisbane, Gold Coast and Regional Queensland

Wood Dust Fire and Explosion

Wood Dust Fire and Explosion

What are the fire and explosion hazards of wood dust?

Wood dust is considered to be explosive if ignition of part of a cloud of wood dust results in the propagation of flame through the rest of the cloud. The burning of an unconfined wood dust cloud produces a flash fire. However, if the wood dust is contained within a full or partial enclosure, the pressure build-up can produce a destructive explosion. Its severity will depend on a number of factors, generally, the larger the volume of the exploding dust cloud, the more widespread its effects will be.

It is important to ensure that wood dust does not escape from collection systems and be allowed to build up within workrooms. If dust does accumulate, any primary explosion which occurs in a collection unit may stir up dust deposits within the building which houses the plant. Burning particles from the primary explosion can ignite the dust cloud resulting from it, leading to a secondary explosion that is usually more destructive than the first.

The explosibility of wood dust

You should assume that all wood dust is potentially explosive. . Wood waste usually has a dust explosion risk where the mean particle size is less than 200 microns, and where as little as 10% of the mixture contains dust less than 80 microns in size.

Explosive Wood dust is commonly produced by:

  • fine cutting (eg sanding) – which produces a dust of very fine particle size;
  • sawing and machining hardwoods – often producing wood waste containing considerably
  • more dust than that from softwood;
  • the processing of MDF, chipboard and similar boards by machining and sawing – which can be expected to produce waste containing much fine dust;
  • profiling and moulding components on routers, spindle moulders etc.

Sources of ignition for wood dust

Common ignition sources include naked flames, faulty or unsuitable electrics and impact sparks.

The sanding or hogging of off-cuts containing metal may produce friction sparks, which can cause sawdust to smoulder and subsequently be fanned into fires or explosions. Use dedicated collection systems for these operations. Consider spark detection and extinguishing devices where there are significant risks.

Hot work involving the careless use of welding or flame-cutting equipment has resulted in many incidents. To prevent this, plant should be isolated and thoroughly cleaned before work starts. Use cold cutting methods whenever possible.

Electrical equipment should be sited away from dusty areas. If this is not practicable, ensure it is adequately protected.

Collection systems for wood dust

There are three main types of system for collecting wood waste:

  • One or more woodworking machines are exhaust ventilated to a nearby collection unit within the workshop which does not form part of any other exhaust ventilation system.
  • Many (perhaps all) of the woodworking machines are ventilated to a collection unit, which can be some distance from the machines and may be inside or outside the workshop (see Figure 1).
  • One or more woodworking machines are exhaust ventilated to a nearby collection unit. These units deliver the wood waste into a larger collection unit, usually outside the workshop. This is known as a ‘through flow’ system.

Ductwork for wood dust

Make ductwork as short as possible with a minimum number of bends. The design should specify a minimum transport (or conveying) velocity of 20 m/s to minimise dust deposits. Use only conductive materials for ductwork so that any static electricity generated can be discharged to earth. Ductwork needs to be regularly inspected internally and cleaned to prevent any accumulation of dust. Suitable access points/hatches should be provided for this.

Collection units for wood dust

There are a number of different kinds of collection unit and the main types are:

  • unenclosed fabric filter sock collector;
  • unenclosed fabric multi-sock collector (see Figure 1);
  • enclosed fabric single-sock collector;
  • enclosed fabric multi-sock collector;
  • cyclone; and
  • bin or hopper.

Precautions for collection units where there is a risk of dust explosion

Collection units should normally be sited outside, away from areas where there may be people. If units have to be indoors, precautions will depend on the size of the collector; the size and construction of the room it is in; the number of people nearby; and how near they are to walkways and combustible materials.

To avoid the risk from secondary explosion or fire, it is essential to enforce good housekeeping practices to prevent the accumulation of wood dust within the building, eg a formal cleaning regime using appropriate vacuums fitted with HEPA-type filters.

Sock collectors (<0.5 m3/s capacity)

Unenclosed sock collectors would quickly disintegrate if the contents were ignited, but would not produce high explosion pressures or widespread effects. Fire risks may exist so, if unenclosed, do not position them within 3 m of workers, combustible materials or walkways. Alternatively, provide a suitable baffle or deflector plate or enclosure (see below). Enclosed sock collectors should discharge at the top to a safe place i.e. above head height.

Sock collectors (0.5–2.5 m3/s capacity)

Ignition of wood dust can lead to a jet of flame at head height, but an explosion is not likely. Where such collectors must remain within the workroom, provide one of the following precautions:

  • Total enclosure within a strong metal cabinet with either an air outlet large enough in area to act as explosion relief or explosion vents. Outlets or vents should preferably discharge to a safe place outside the workroom or, if inside, discharge at least above head height.
  • A baffle or deflector plate made of non-combustible material to direct flames or burning material to a safe place.
  • Ensure the fan can be turned off from a safe place if a fire starts in the filter. A 3 m separation between the filter and regularly occupied locations is likely to be adequate to protect employees.

Sock collectors (>2.5 m3/s capacity)

Site these outside or enclose them in a strong cabinet fitted with explosion vents that discharge to a safe place.

Cyclones for wood dust

Well-made cyclones of less than 0.5 m3/s volume (rare in woodworking) do not usually require explosion relief panels. Larger low-efficiency cyclones usually have large enough air outlets to act as an explosion vent, but the need for additional explosion venting should be assessed. Larger high-efficiency cyclones do not usually have large enough air outlets to act as effective explosion vents and so additional venting will be necessary. Where cyclone air outlets discharge to an after filter, both the cyclone and the after filter will need explosion-relief panels.

Bins or hoppers for wood dust

Where used to store explosible wood waste, these will require explosion relief appropriate to their volume. They should preferably be outdoors but, if indoors, additional explosion relief may be required on the building itself. There should also be a safe system of work for emptying bins and hoppers.

Interconnected plant for wood dust

Take precautions to prevent an explosion spreading between interconnected units of plant, such as collectors, cyclones, filters and incinerators. Collectors should discharge their collected wood waste through an explosion choke, eg a rotary valve, or directly into strong metal containers clamped firmly to the discharge outlets.

Sizing of explosion relief for wood dust

The simplest and most common method of protecting process plant against the consequences of a dust explosion inside it is to provide some deliberate weakness in the structure in the form of explosion relief vents. Suitably sized and sited vents will ensure any explosion within the plant will be vented safely.

Fire fighting

Consider installing a dry sprinkler system and a C-coupling for attachment to a fire-brigade hose (on new plant). Make sure access doors on silos are big enough to allow access for fire fighting. Use gently applied water (eg a spray or mist), not jets to extinguish fire, to minimise the disturbance of burning wood waste

Additional precautions for wood dust explosions

Users should take the following practical precautions to minimise fire and explosion risks:

Ensure there is a preventive maintenance regime for the entire collection system

  • Leave the fan running for some time after the machines have been turned off to ensure the ducts are empty when the air flow stops, and minimise dust fall-out in the ducting.
  • Keep the system dust-tight.
  • Replace seals, gaskets and covers as necessary.
  • Empty containers associated with filters regularly.
  • Take care to prevent metal objects entering the collection system.
  • Smouldering fires often precede explosions – if a fire is suspected, stop the air flow through the collection system before investigating the problem.

For detailed advice on assessment and specific control measures for your workplace contact our consultants.

For further information on workplace monitoring, testing and assessment click here.

Haztek: Servicing Sunshine Coast, Brisbane, Gold Coast and Regional Queensland

Wood Dust Exposure

Wood dust

What you need to know aboout wood dust exposure

Wood dust can cause serious health problems. It can cause asthma,  carpenters and joiners are four times more likely to get asthma compared with other workers. Work Health and Safety Legislation require that you protect workers from the hazards of wood dust.

Hardwood dust can cause cancer, particularly of the nose.

Settled dust contains the fine particles that are most likely to damage the lungs.

What you need to do to control wood dust exposure

Exposure limits for wood dust

Safework Australia have set exposure standards for hardwood (1mg/m3) and softwood (5mg/m3), these exposure standards must not be exceeded. These are limits placed on the amount of dust in the air, averaged over an eight-hour working day. However, you must reduce exposure to wood dust to as low as ‘reasonably practicable’.

Implement Control Measures for wood dust

Extraction for wood dust

Provide dust extraction (also known as local exhaust ventilation or LEV) at woodworking machines to capture and remove dust before it can spread.

Design the extraction system to take into account:

  • the number and type of machines to be connected to it, the ones that are used together and the layout of the workshop or factory. This information should be supplied by the user.
  • the machine manufacturer’s information or an experienced body’s information on required air flow and extraction vacuum for each extraction connection for each machine.

Educate workers about the risks from wood dust and the control measures required. They should know how to use the extraction properly. Fitting air flow indicators will help, as these will show them if it is working correctly, for example if dampers are open or shut and also if maintenance is required.

Keep the extraction system properly maintained and working correctly (it is a legal requirement to have it examined every year). Follow the extraction manufacturer’s guidance for maintenance requirements.

Sweeping Wood Dust and Compressed Air

Never sweep up or use compressed air lines as this will disturb the dust and allow it to become inhaled. Always clean up using a suitable vacuum cleaner with HEPA filters, or a vacuum attached to the extraction system.

Respiratory Protection for wood dust

For very dusty jobs such as sanding, additional protection may be needed and a suitable face mask should be worn as well as using the extraction.

Where you need to use RPE you should:

  • select the right mask and cartridge
  • ensure it fits properly by having it face fitted, and by being clean shaven
  • look after it / change it regularly in accordance with the manufacturers’ instructions

Health surveillance for wood workers

Because wood dust causes asthma any health effects must be picked up early. This can be done using health surveillance].

For most woods, low level health surveillance will do. When someone first starts in a job where they are exposed to wood dust they should fill in a questionnaire.

After six weeks they should then complete a follow up questionnaire and this should then be repeated every year.

These questionnaires tell you what to do if you think someone has been affected.

A higher level of health surveillance, including lung function testing, is needed for exposures to woods such as western red cedar which are a known asthma causing agent.

 For detailed advice on assessment and specific control measures for your workplace contact our consultants.

For further information on workplace monitoring, testing and assessment click here.

Haztek: Servicing Sunshine Coast, Brisbane, Gold Coast and Regional Queensland


A Strategy for Assessing and Managing Occupational Exposures

Introduction to Assessing and Managing Occupational Exposures

In Australia we have a legal requirement to protect all who work on or visit our sites or premises from occupational illness or injury. To maintain competiveness in a global economy it is essential that this is achieved through an effective and efficient program. Prior to developing workplace monitoring or health surveillance programs a comprehensive understanding of workplace exposures is required to ensure appropriate cost-effective programs are developed.

Many people carry out risk assessment on a day-to-day basis during the course of their work. They note changes in working practices, they recognise unsafe working conditions and practices, and often they take appropriate corrective action. However risk assessments need to be conducted systematically to deliver real and lasting benefits to worker health.

The American Industrial Hygiene Association (AIHA) Strategies for Assessing and Managing Occupational Exposures prescribes a methodology which when adopted provides a systematic and cost-effective program for assessing workplace exposures. This program has been adopted for use in the Australian work environment through the Australian Institute of Occupational Hygienist (AIOH) Simplified Occupational Hygiene Risk Management Strategies Guidelines.  The guideline has been developed to meet Safework Australia’s requirements and will assist in achieving compliance with the Model Work Health & Safety Laws which will be enacted early 2012.

Occupational Health Hazard Identification

Health hazard identification is the first step to develop an occupational hygiene program. This process will develop a list of the stressors that the workforce is potentially exposed to. These will be under the categories of Chemical (Solvents, Pesticides), Physical (Vibration, Heat, Noise), Biological (Mould) and Ergonomic. The health hazard identification needs to be conducted in consultation with operational staff, the process usually involves:

  • A review of the materials/chemicals and their material safety data sheets (MSDS);
  • A review of the process, including exposure scenarios e.g. the tracking of trace amounts of highly toxic substances;
  • A walk-through survey, and consultation with operational personnel regarding processes, equipment, materials used, physical environment, products / by-products, etc;
  • A review of documented monitoring or information from similar types of assessments;
  • A review of reported incidents.

Establishing Similar Exposure Groups for Occupational Health Hazards

The next step is to establish Similar Exposure Groups. A Similar Exposure Group (SEG) is a group of people having the same general exposure profiles because of the similarity and frequency of the tasks they perform and materials and process with which they work. A properly defined SEG provides the ability to use data from a relatively small sample of the exposure population to predict the likely chronic health exposures of the group as a whole.

Risk Assessment for Health Hazards

Assessments involve qualitative and semi-quantitative risk assessments that are performed to identify potential exposures that require inclusion in the monitoring program. This is a risk management process to establish the priority exposures for further review and uses surrogate data, modelling and the judgment of the hygienist, engineers, managers and operators. Resources for health surveillance and workplace monitoring can then be focused on the priority areas where further information is required to define exposures.

Health Surveillance

Health surveillance, of a person, means monitoring the person to identify changes in the person’s health status because of exposure to a hazardous chemical.

The Workplace Chemicals Model Regulations require that health surveillance be conducted when:

  • there is a significant risk to the health of a worker arising from exposure to a hazardous chemical listed at Schedule 3; or
  • a risk assessment identifies a significant risk to the health of a worker arising from exposure to any hazardous chemical and there are valid techniques for detecting indications of the health effect; or
  • a valid method for determining biological exposure exists for a hazardous chemical and there is uncertainty, based on reasonable grounds, as to whether a safe level may be exceeded.

The Model Work Health and Safety Regulations provide specific requirements for health surveillance for workers conducting specified lead work or certain asbestos removal or maintenance work.

Blanket heath surveillance programs (full health surveillance for all workers) are extremely expensive. They disrupt workforce scheduling and create unnecessary anxiety with the workforce (why am I getting health surveillance for asbestos when I have been told that I do not work with asbestos containing material).

Systematic hazard identification and risk assessment to determine occupational exposure profiles assists with focussing health surveillance on the groups where a need has been identified.

Workplace Monitoring

Monitoring means to survey regularly all measures which are used to control hazardous chemicals in the workplace. This includes the monitoring of atmospheric contaminants, but does not include biological monitoring which is an element of health surveillance.

The Workplace Chemicals Model Regulations require that monitoring is undertaken to determine the concentrations of hazardous chemicals in the workplace when:

  • there is uncertainty, based on reasonable grounds, as to whether an exposure standard may be exceeded or;
  • monitoring is necessary to determine whether there is a risk to health.

Blanket monitoring programs are extremely expensive and can disrupt workforce scheduling.

Systematic hazard identification and risk assessment to determine occupational exposure profiles assists with focussing monitoring programs on the groups where a need has been identified.

Our Experience ?Assessing and Managing Occupational Exposures

Our principal consultant, Maurice Barnes, has professional qualifications in Science, Occupational Health and Safety and Occupational Hygiene and is a Chartered Profession Member of the Safety Institute of Australia and a Member of the Australian Institute of Occupational Hygienist. Maurice has over 15 years experience in the field of occupational health and safety including experience conducting audits and risk assessments for waste and treatment facilities including sewerage treatment plants.

Recent projects completed by our principal consultant include:

Conduct health hazard identification and risk assessment and develop health surveillance and monitoring programs for Australian Navy Ships and Submarines. This project was completed on behalf of the Defence Centre of Occupational Health under direction from the Defence Minister.

Assistance to regional councils in the conduct of risk assessments and development of work method statements for their waste water and treatment facilities including the sewerage treatment plant.

Conduct of detailed risk analysis and personnel exposure monitoring for maintenance personnel exposure to contaminated soil and water during site remediation work.

Some Benefits of implementing a Strategy for Assessing and Managing Occupational Exposures

Cost Savings for Health Surveillance Program

Without systematic hazard identification and risk assessment a blanket health surveillance program is often implemented.  Through implementing a strategy for assessing and managing hazards a targeted health surveillance program can be adopted. The below table shows estimated costs of a blanket health surveillance program compared to a targeted approach for a workforce with 500 operational people.

Type of Assessment Full Assessment Partial Assessment Minimal Assessment Total Cost / Year
Cost of Assessment $600 $400 $200  
Blanket Health Surveillance Program 500 employees - - $300,000
Targeted Health Surveillance Program 100 employees 200 employees 200 employees $110,000

The cost of a health surveillance program is not necessarily a new cost for organisations, in many cases health surveillance is already conducted i.e. medical checks for all workers who conduct confined space entry and hearing assessments. Adopting a systematic strategy is about integrating and targeting resources so that they are effective and compliance is achieved.

Cost Saving of Workplace Monitoring Program

Similar savings can be made in workplace monitoring programs. This is harder to quantify as we don’t yet know what monitoring is required. In a lot of situations using this assessment methodology allows risk assessments to be conducted using surrogate data (exposure data from other workplaces) and modelling, again providing significant savings. In some situations surrogate data and modelling is more reliable and provides stronger evidence of the exposure profile as it draws from large assessment programs that an individual organisation could not resource.


The cost savings in health surveillance and workplace monitoring are advantages of adopting this strategy but they are not the main benefit. A thorough understanding of exposures allows the occupational hygiene program, including control efforts, to be prioritised to protect employees and manage exposure related risks.  It also puts the organisation in position to manage the unpredictable changes that will occur both in knowledge of health-effects of environmental agents and in society’s tolerance of workplace exposures.

Development of a comprehensive exposure assessment program is encouraged because a comprehensive program is the best way for organisations to understand and manage the ever-broadening realm of occupational health related risks.

For detailed advice on assessment and specific control measures for your workplace contact our consultants.

For further information on occupational health and hygiene hazards click here.

Haztek: Servicing Sunshine Coast, Brisbane, Gold Coast and Regional Queensland