Key messages

Members of the Latrobe Valley community have contacted us with questions about the Ash residue in roof cavities project – we’re sharing the answers to make sure everyone is informed.

About the project

  • What is the project about?

    In February 2014 the Hazelwood brown coal mine fire burnt for 45 consecutive days, becoming the largest and longest fire in the history of the Latrobe Valley.

    At the time, the Latrobe Valley was impacted by smoke and ash from the burning brown coal. As a result, brown coal ash is present in the space between the ceiling and the external roof (roof cavities) of some houses in Morwell. 

    The Hazelwood Mine Fire Inquiry recommended that the government test and analyse any ash that may have settled in the roof cavities of houses in Morwell and provide advice about any potential known or unknown health effects. The second part of the recommendation requires the government to assess people’s exposure to the ash and develop an action plan to remove the ash from affected houses if the testing reveals that ash contained in the roof cavities could cause any negative or unknown impacts on human health.

    The ‘Ash residue in Morwell roof cavities’ project addressed this recommendation and also allowed government agencies to better understand the community’s concerns about ash residue in roof cavities. 

    The project was completed and a final report was released in June 2017. More information about the results and independent expert’s recommendations are detailed below. The final report is available on the Ash Project.

     
  • How was the project completed?

    An independent expert collected samples and analysed the ash and dust contained in 50 roof cavities in Morwell. Samples from 10 roof cavities in another area in the Gippsland region with similar environmental factors (Rosedale) were tested for comparison.

    The study looked at the chemical make-up and amount of roof cavity dust and ash residue in the 60 houses. They tested the levels of 19 contaminants and measured the levels against nationally recognised health investigation levels. Any contaminants that were found to be above the health investigation levels were investigated further to assess the extent of the community's exposure and whether the contaminants could cause any potential health risks to residents.

  • Who led the project?

    DHHS led the ‘Ash residue in Morwell roof cavities’ project. Throughout the project, DHHS worked closely with the community, Latrobe Health Assembly, Latrobe City Council and the Environment Protection Authority (EPA) Victoria.

  • Who is the independent expert?

    The environmental consultancy Senversa Pty Ltd was appointed as the independent expert in August 2016. Senversa employs environmental health scientists specialising in environmental health and risk assessment. 

    More information about Senversa is available at www.senversa.com.au

     

About Inquiry Report III and Recommendation 9

  • Did the project look at what else was burning in the fire (other than brown coal from the mine)?
    No. Recommendation 9 of Inquiry Report III made it very clear that the primary objective of the project was to identify whether brown coal ash associated with the 2014 Hazelwood brown coal mine fire is present in Morwell roof cavities and assess whether that ash residue might pose a potential health risk to residents.
  • What has happened since the Inquiry Report III was published, which includes the recommendation about investigating ash residue in roof cavities in Morwell?

    Hazelwood Mine Fire Inquiry Report 2015/2016 Volume lll – Health Improvement (Inquiry Report III) was tabled in the Parliament of Victoria in February 2016. This report includes Recommendation 9, relating to the Ash residue in Morwell roof cavities project. The Victorian Premier and Minister for Health announced that the Government had accepted all recommendations from Inquiry Report III, including the testing and analysis of ash residue in roof cavities, on 15 April 2016.

    In May 2016, the 2016-17 Budget allocated funding to support the implementation of the recommendations in Inquiry Report III (including Recommendation 9). Planning was underway to implement the project in June 2016, including the development of a dedicated website and generic email address to facilitate the recruitment of houses for testing, and engagement of an independent expert.

    The procurement process to engage an independent expert closed on 22 July 2016. The successful independent expert (Senversa) was engaged via a DHHS contract in August 2016. Contracts are published on www.tenders.vic.gov.au.  

    Community forums were held in Morwell in September 2016. Senversa also developed the Sampling and Analytical Quality Plan (that was made publicly available via the department’s website) that sets out how houses were selected for testing and began collecting samples in Morwell. Senversa finished collecting samples from all of the 50 selected houses in Morwell in October 2016. 

    Senversa began collecting samples from the control site in Rosedale in late-November 2016. Samples from Morwell were tested via Victorian laboratories.
    In December 2016, Senversa provided preliminary results of the testing for Morwell houses. The preliminary results for Morwell were provided at this time to account for a slower than anticipated recruitment of houses in Rosedale. Sampling was completed in Rosedale in December 2016 and those samples were tested. Senversa analysed and compared the results.

    Community forums were held in Morwell to discuss the final results and possible next steps in January 2017. Senversa also carried out individual visits with people whose houses were tested to discuss the results and provided a report to each household that was involved. The individual visits were completed in February 2017.
    The project team shared the results of sampling with the Executive Board of the Latrobe Health Assembly in early March 2017. The Board recommended a peer-review of Senversa’s draft final report. This work was undertaken by CDM Smith Australia Pty Ltd in March.

    In April 2017, Senversa revised the draft final report in response to the peer review. The department started working on a community report that made the information in the final, technical report easier to understand. The department consulted with members of the community to make sure the community report was clear, concise and easy to understand.

    Senversa’s final report and the community report were released in June 2017. 

     

     

  • What does the second part of Recommendation 9 actually mean – is the action plan about cleaning?

    The project needed to address the first part of the recommendation before considering what action (if any) was necessary to protect the health of residents. Senversa's study showed that brown coal ash residue from the 2014 Hazelwood brown coal mine fire that remains in some roof cavities is unlikely to pose any risk to the health of Morwell residents.

    Senversa therefore recommended that the removal of ash or dust from roof cavities is not necessary or warranted for the long-term health of people living in houses impacted by the fire.

    The government accepted Senversa’s recommendations in June 2017.

     

About the independent expert’s findings

  • How much ash residue was found in people's roof cavities?

    The amount of ash residue in people's roof cavities varied from house to house.

    In the roof cavities of most, but not all, of the houses tested in Morwell, Senversa found a layer of fine-grained darker dust with a layer of coarser-grained white to pale orange material on top of it. The independent experts inferred the lighter layer on top was brown coal ash. This lighter layer was not observed in Rosedale.

    Senversa estimated the amount of ash residue visually. Houses with metal roofs had less dust than houses with tiled roofs. This may be because there are fewer gaps for dust to enter the roof cavity. Roof cavities that had foil insulation or 'sarking' had even less dust.

    In general, there was more ash in the roof cavities of houses closer to the site of the fire. These results were statistically significant, meaning there is a strong link between distance from the fire and the amount of ash. Houses with the highest amounts of roof cavity ash were all within 500 metres of the fire front. Generally, houses further away from the fire had less ash and 12 Morwell houses had no visible ash.

  • Is ash from the roof cavity entering people's houses?

    The independent experts collected dust samples from surfaces inside the living area of the house to find out whether ceiling dust or ash was entering the house from the roof cavity.

    Because the samples of roof cavity dust and indoor dust were collected in different ways, the samples couldn’t be accurately compared. Senversa therefore hypothesised that if dust in the house was made up of dust from the roof cavity, the chemical make-up of the two samples would be similar. This was not the case. The chemical make-up of roof cavity dust and indoor dust was very different. This supports the finding that roof cavity dust is not entering the living areas of houses.

    Indoor dust is usually made up of things like dirt from outside, road dust, human and pet hair and skin, carpet and clothing fibres, paint chips and fungus spores.

  • What were the results of testing and analysis?

    Senversa’s study showed that brown coal ash residue from the 2014 Hazelwood brown coal mine fire that remains in some roof cavities is unlikely to pose any risk to the health of Morwell residents.

    The study looked at the chemical make-up and amount of roof cavity dust and ash residue in 50 houses in Morwell. Roof cavity dust in 10 houses in Rosedale was also tested and compared with the Morwell results.

    Nineteen contaminants were tested. These were:

    • antimony
    • arsenic
    • boron
    • barium
    • beryllium
    • cadmium
    • chromium
    • cobalt
    • copper
    • lead
    • manganese
    • mercury
    • nickel
    • polycyclic aromatic hydrocarbons (PAHs)
    • selenium
    • strontium
    • titanium
    • vanadium

    Only three contaminants – antimony, lead and zinc – were found at elevated levels in any of the 60 houses. One house in Rosedale had an elevated level of polycyclic aromatic hydrocarbons (PAHs).

    Total number of houses tested Number of houses with elevated levels of lead Number of houses with elevated levels of zinc Number of houses with elevated levels of antimony Number of houses with elevated levels of PAHs

    Morwell

    50

    14

    4

    2

    0

    Rosedale

    10

    5

    1

    1

    1

     

    In all cases, Senversa's research suggests the elevated levels of contaminants were not caused by the 2014 Hazelwood brown coal mine fire. This is because the levels were similar in the two towns. The independent expert concluded that the levels of contaminants did not pose a long-term risk to human health. The study also suggested that dust and ash residue from the roof cavity was not entering the living areas of the house. This is because the chemical make-up of roof cavity dust and ash was different to samples taken from inside the house. There was also no evidence that brown coal ash residue was causing red mould to grow in houses.

    More detailed information about the results is available in Senversa’s final report or the community report available at: www.health.vic.gov.au/ash-project

  • What recommendations did Senversa make in its final report?

    Senversa's study showed that brown coal ash residue from the 2014 Hazelwood brown coal mine fire that remains in some roof cavities is unlikely to pose any risk to the health of Morwell residents.

    Senversa therefore recommended that the removal of ash residue or dust from roof cavities is not necessary or warranted for the long-term health of people living in houses impacted by the fire.

    The government accepted Senversa’s recommendations in June 2017.

  • What did Senversa compare the levels of contaminants against?

    Senversa needed a standard to understand how the chemical make-up of the dust samples could possibly affect human health. However, there are no international or Australian recognised standards for human health risks relating to roof cavity dust or for ash. Senversa therefore used the health investigation levels (HILs) for soil contamination as a trigger point for more detailed investigation.

    The HILs for soil contamination were considered the best standard to use. This is because the chances of a person coming into contact with soil are much higher than the chances of a person coming into contact with ash or dust contained in a roof cavity. This means using this standard is highly precautionary.

     
  • What are health investigation levels or HILs?

    A health investigation level is a level above which further investigation may be needed to determine whether a significant health risk exists.

    If the level of a contaminant meets or is higher than the HIL, it does not mean there is health risk. Levels higher than HILs do not automatically mean that clean-up is required. HILs are simply used to indicate that further investigation may be needed.

     
  • Why did Senversa use the health investigation levels for soil?

    Because there are very few (if any) studies on roof cavity dust, Senversa used the HILs for soil contamination. These are Australian standards published under the National Environment Protection Measures. There are no international or Australian recognised standards that set a level for contaminants in roof cavities to cause a health risk.

    The HILs for soil contamination were considered appropriate and protective of health, because the chances of exposure to soil are much higher than the chances of exposure to dust or ash in a roof cavity. This means using this standard is highly precautionary.

    The levels are deliberately set well below what would impact the health of the most vulnerable people, even after long-term exposure. For example, a child playing in the dirt in their garden every day.

  • At what levels were the contaminants found in the samples?
    At what levels were the contaminants found in the samples? How much higher than the health investigation levels were antimony, lead, and zinc?

    The levels of contaminants in roof cavity dust and ash varied from house to house, but the majority were below the health investigation levels. The following table sets out the lowest and highest levels of contaminants found in Morwell and Rosedale roof cavity dust samples, and the relevant health investigation levels for soil.

  • Why are these elevated levels considered safe for residents?

    While antimony, lead and zinc exceeded the health investigation levels in some roof cavities in Morwell and Rosedale, the reported concentrations are consistent with expected background contamination sources and do not appear to be associated with coal dust or with brown coal ash residue.

    In its final report, Senversa notes that the magnitude by which chemical concentrations in roof cavity dust exceeded the health investigation levels (HILs) was relatively low (less than 10-fold).

    Because there are no standard health investigation levels for roof cavity dust or ash residue, Senversa used the HILs for soil contamination. The health investigation levels are deliberately set well below what would impact the health of the most vulnerable people, even after long-term exposure. For example, a child playing in the dirt in their garden every day.

    These HILs are therefore very protective of health, because the chances of being exposed to soil are much higher than the chances of being exposed to dust or ash in a roof cavity. This means using this standard is highly precautionary.

    It should be noted, however, that roof cavity dust in general – in Morwell or anywhere else – may cause respiratory effects if the dust is disturbed and inhaled (e.g. coughing, sneezing or irritation to the eyes, throat and nose). All roof dust may also contain a range of hazardous materials that should be avoided.

    Further information on the hazards in roof cavities and ways of minimising risks can be found on the health.vic website.

  • Why does Senversa conclude that the elevated levels of contaminants were not caused by ash residue from the 2014 Hazelwood brown coal mine fire?

    Senversa's research suggests the elevated levels of contaminants were not caused by the 2014 Hazelwood brown coal mine fire. This is because the levels were similar in samples taken from Morwell and Rosedale roof cavities.

    The levels of lead were higher than the health investigation levels (HILs) in 14 of the 50 houses in Morwell and five of the 10 houses in Rosedale. The levels were similar in houses in both towns. Senversa found there was a link between the age of the house and the lead levels: the older the house, the higher the level of lead. But there was no link between elevated lead levels and the location of the houses or distance from the fire. Senversa therefore concluded that the elevated lead levels were not likely to be caused by the fire. They suggest the presence of lead is a residue of emissions from leaded petrol and/or the historic use of lead in paints and other building materials. Lead in petrol was phased out by 2002 and in paint during the 1970s.

    Zinc was found above its HIL in four houses in Morwell and one house in Rosedale, again at similar concentrations in both places. The houses with elevated levels of zinc had galvanised metal roofing materials, where zinc is used to prevent rusting. Over time, the roofing materials can deteriorate and zinc particles are added to roof cavity dust. In both towns, the levels of zinc were about ten times higher in houses with metal roofs compared to houses with tile roofs. Senversa suggest that metal roofing is the likely cause of elevated zinc levels in some houses.

    Antimony exceeded its HIL in two houses in Morwell and one in Rosedale. Houses with foil insulation had the highest levels of antimony in the roof cavity dust. Reflective foil or 'sarking' provides insulation and weather protection, with some types made up of 10% antimony trioxide. Over time the insulation can degrade and small pieces of the material are added to roof cavity dust. Senversa therefore suggests the foil insulation is the likely cause of elevated antimony levels in some houses.

     
  • How do I know the results are reliable?

    DHHS appointed an independent expert, Senversa, to run the project. Senversa has expertise in scientific analysis and testing, project management, health risk assessment and engaging with communities.

    In early March 2017 the Latrobe Health Assembly Executive Board recommended that DHHS get a second opinion on Senversa's findings to make sure the project was completed in the best way possible, and the results were consistent and reliable. An independent peer review was completed by CDM Smith Australia Pty Ltd in March 2017. The peer review supported Senversa's findings.

     

What happens now that the project has finished?

  • How can I get a copy of the final report?

    Anyone who registered to receive project updates was sent an executive summary of the final report (prepared by Senversa) and the community report (prepared by DHHS). 

    Hard copies of the executive summary and community report are also available via local community groups and community hubs, such as the library, RSL, and council offices. 

    All project materials are published on the project web page.

    Anyone can request a copy of the full final report and community report by:

  • Will the results of this project be fed into the Hazelwood Health Study?
    The Long Term Health Study is an observational study, which means collection and analysis of information about the health of study participants and generally does not include diagnosis, treatment and health interventions. The information gained from the Long Term Health Study will be used to assess the potential long-term impacts of the 2014 Hazelwood brown coal mine fire on the health of affected communities. The results of this project will contribute towards the wider objective of the Long Term Health Study, which is to inform health innovation and investment in the Latrobe Valley in the coming years as well as inform the health response for any other community affected by an event similar to the Hazelwood coal mine fire in the future.
  • Will the results of the Ash project be compared with people’s health records?

    No. The purpose of the project was to assess the potential health risk to the community from brown coal ash residue remaining in roof cavities, as a result of the 2014 Hazelwood brown coal mine fire.

  • Will the project look at fungus in the roofs?
    No. The purpose of this project is to assist in addressing Recommendation 9 of Inquiry Report III, which is specific to ash residue as a result of the Hazelwood coal mine fire contained in roof cavities of residences in Morwell.
  • Should I be worried about ash that is accumulating on down-lights or other areas in my house? Could it be a fire hazard?
    According to Energy Safe Victoria, downlights pose a fire risk if they become covered by insulation or ceiling debris (including dust or ash residue).

    For more information refer to Energy Safe Victoria/

  • Does rainwater affect ash? Does it change its chemical structure?
    Rainwater would potentially aid in leaching and dissolution of metals and other chemicals from the ash into the soil or water it has landed on. Rainwater will also wash away and remove the ash from most structural surfaces where rainwater can penetrate.
  • What is the ash physically expected to look like?
    The literature review provided Senversa with a description of the physical appearance of the ash. The ash is lighter in colour than coal dust, is orange to orange brown and is fine to coarse grained.
  • Is the chemical make-up of the ash known?
    Yes. Senversa undertook a literature review to understand the chemical make-up of the ash. Based on the results of the literature review, including analytical results for ash samples collected by EPA Victoria during the fire at the Hazelwood coal mine, the primary components of the ash are expected to be trace elements and metals. Many of these are likely to be present at concentrations similar to or lower than those present in natural soils.

    Elements which may be present at higher concentrations in ash than background soils include arsenic, antimony, barium, boron, lead, manganese, selenium, strontium, titanium and zinc. Polycyclic aromatic hydrocarbons (PAHs) are also formed during the burning process, and are reported to be present in ash samples, however below concentrations of potential concern for human health. Some other organic and inorganic compounds have also been identified in ash samples, however at very low concentrations that are below background levels in typical soils.

  • Is the ash different to what is in the furnace, wood burner or fireplace?
    Yes. The physical and chemical characteristics of ash in furnaces or fireplaces will depend on the material burned. Ash derived from wood or other organic materials will have different chemical composition and appearance than the ash from the coal mine fire.
  • Do different roof types let in more ash and dust than others?
    Yes. Several houses in Morwell have open slat eves which are likely to allow more dust into the ceiling cavity than sealed eaves. Tiled roofs, especially where the tiles are cracked or in a state of disrepair, allow more dust into the roof space due to the multiple joins where each separate tile connects. Metal roofs consist of large sheets of metal with fewer joins than tiled roofs, allowing less dust into the roof space. Reflective foil insulated roofs provide an additional barrier that may reduce dust load into the roof space.
  • What are the points of entry or modes of exposure to ash and dust inside the house?
    Points of entry for ash and dust from the roof cavity to the inside spaces of a house include, but are not limited to:
    • holes in the ceiling
    • cornices that are cracked or missing with visible gaps into the roof space
    • fans and vent points that are not sealed
    • gaps in ceiling roses
    • gaps in connections between flues and the ceiling.
    Ash and dust may also enter the house during renovation or maintenance activities that disturb ceilings or cavity walls, or that involve entry to the roof space.
  • Can you get filters to prevent dust getting into your home?
    The usefulness of filters for preventing or reducing the amount of dust entering your home from the roof cavity will depend on how the dust is entering. As mentioned above, dust may enter through a range of holes or gaps. Installing filters (e.g. in ducted heating or air conditioning vents) may reduce dust entry (if occurring) via your ducted system, however dust may still enter via other pathways.
  • The ash residue in/around my home was sticky, what could have caused it to be sticky like that?
    It is likely to be a product of the combustion of brown coal called char. Char is the solid material that remains after light gases (e.g. coal gas) and tar have been driven out or released from a carbonaceous material during the initial stage of combustion, which is known as carbonisation, charring, devolatilisation or pyrolysis.
  • Is it safe to go into my roof cavity?
    Residents are advised not to go into their roof cavities without expert advice or without following safety precautions. For more information about hazards in roof cavities read Hazards in roof cavities or phone 1300 761 874 during business hours.

About community engagement

  • How was the community informed about the results?

    The results were shared through the community updates, the project web page and community meetings. People who had their roof cavity tested were visited individually to discuss the results. The final project report by Senversa includes the methodology, results and recommendations.

    Anyone who registered to receive project updates was sent an executive summary of the final report (prepared by Senversa) and the community report (prepared by DHHS).

    Hard copies of the executive summary and community report are also available via local community groups and community hubs, such as the library, RSL, and council offices. 

    All project materials are published on the project web page.

    Anyone can request a copy of the full final report and community report by:

    • emailing ashproject@dhhs.vic.gov.au
    • phoning 1300 761 874
    • returning the request form included with the community report
    • completing the online form or downloading a request form on the project web page.
     
  • How did the government keep the community up to date during the project?

    DHHS kept people informed throughout the project and regularly checked with community members and local groups to make sure they were getting enough information and that it was being provided in the right way. Registered participants received monthly updates via the mail or by email. 

    The project team held community forums in September 2016 and January 2017 to discuss how the project would run and share the final results.

    People who had their roof cavity tested were visited individually to discuss the results.

  • How did you reach people that don’t have access to a phone or the internet?

    As well as taking calls from members of the public and publishing information on the dedicated project page, we are communicated with the community in a number of ways, including:

    • advertising in the Latrobe Valley Express
    • posting letters and other information to people who registered their interest in the project
    • emailing people who registered their interest in the project
    • Victorian Government leaders holding events, making speeches and publishing media releases
    • posting information, updates and invites on social media
    • holding community forums
    • notifying local media of upcoming events and project milestones
    • providing information for community groups to have available at their facilities, distribute at their meetings and promote via social media
    • providing hard copy documents at the offices of the Latrobe City Council and Department of Health and Human Services in Morwell.
     
  • How will you reach people who don’t speak English?
    We will make sure key project resources are available in a number of community languages to ensure everyone has access to project information and results.
  • How did you reach people who didn’t register their interest in the project?

    People who didn’t register to receive updates could find out about the project by:

    • reading the local paper, listening to the radio and watching local TV news
    • looking at the project’s dedicated web page
    • attending community forums
    • checking social media
    • taking part in community groups we engaged with

    seeing hard copy publications in local community hubs and government offices.

  • How did you reach other communities in the Latrobe Valley?

    People living outside Morwell could find out about the project through local media, advertising in the local paper or by checking the department’s website. Community forums were open for anyone to attend. Everyone can access the dedicated project web page or follow DHHS on social media.

  • What support services are available for people who have experienced trauma as a result of the fire and prolonged exposure to smoke?
    Latrobe Community Health Service offers services in Morwell to assist people who have experienced trauma as a result of the fire and prolonged exposure to smoke.

    Phone the Latrobe Community Health Service on 1800 242 696 to discuss your individual situation.

  • Could the ash in my roof cavity affect, or be responsible for, sleep disorders such as sleep apnoea?
    No. Obesity is one of the most common causes of sleep apnoea. Other contributing factors include:
    • alcohol, especially in the evening – this relaxes the throat muscles and hampers the brain’s reaction to sleep disordered breathing
    • certain illnesses, such as reduced thyroid production or the presence of a very large goitre
    • large tonsils, especially in children
    • medications, such as sleeping tablets and sedatives
    • nasal congestion and obstruction
    • facial bone shape and the size of muscles, such as an undershot jaw.
    For more information please refer to the Better Health Channel at: https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/sleep-apnoea
  • Could illness like colds, flu or respiratory disease be related to exposure to ash from the Hazelwood coal mine fire?
    Exposure to ash us unrelated to cold, flu or respiratory disease. Ash may irritate the skin, eyes, nose and throat. Ash particles are too big to be breathed deep into the lungs so are unlikely to cause either short- or long-term health effects.
  • Were asbestos materials burned in the fire?
    It is very unlikely that asbestos materials were burnt in the 2014 coal mine fire as it was the brown coal that caught alight.

    Research has shown that fires involving asbestos-containing materials (e.g. houses) do not result in levels of asbestos fibres in the surrounding area high enough to cause a risk to health. This is because during a fire the amount of asbestos fibres released into the air is relatively low.

    For more information please refer to the following publications:

  • If the ash/dust found in roof cavities is found to be harmful, but you don’t usually go into your roof cavity, what is the likely risk to people’s health?
    The report being prepared by Senversa (the independent expert) will investigate the potential for residents to be exposed to ash residue, if present, and whether any exposures constitute a potential ongoing risk to human health.

    If the analysis finds that there is ash residue in roof cavities that could be harmful to health, or if the health impacts are unknown, Senversa will assess the extent of the community’s potential exposure to the ash and develop an action plan to manage any risks.

    The government will consider the recommendations made by the independent expert Senversa and work with the community to determine what actions may be necessary.

  • If my roof cavity was cleaned after the fire, is there any ongoing health risk?
    Dust, ash and other materials can collect in roof cavities. The Department of Health and Human Services has prepared a fact sheet titled ‘Hazards in roof cavities’ which sets out information to provide you with the facts about these hazards and steps you can take to protect your health and the health of those in your care. You can find this fact sheet at: www.health.vic.gov.au

    Hazards in roof cavities that are not disturbed and can be isolated from residents do not pose a health risk.

    However, householders may be putting themselves at risk when entering a roof cavity and doing work. There are risks of physical injury (e.g. falls and electrocution) and potential risks from skin contact or breathing in various materials. It is important to be aware of any risks and the steps you can take to keep safe.

About selection criteria

About the sampling process

About testing and analysis of samples

About ash, coal dust and other dust that might be in roof cavities

  • Did this project only looking at ash from the 2014 Hazelwood brown coal mine fire?

    The project tested and analysed the dust in roof cavities in homes in Morwell. In some houses, that dust included ash residue from the 2014 Hazelwood brown coal mine fire.

    Chemicals, dust and other matter (e.g. coal dust from local mines and power stations) may be present in properties in Morwell and adjacent townships. However, in response to Recommendation 9, this project sought to address coal ash residue produced by the Hazelwood coal mine fire only.

     
  • Have there been previous studies of local roof cavities prior to the fire?

    Very few studies about roof cavity dust and ash from coal mine fires have been undertaken in Australia. This project therefore provides useful methods, techniques and baseline information for future studies.

  • Did the project look at fungus in the roofs?

    The purpose of this project was to assist in addressing Recommendation 9 of Inquiry Report III, which is specific to ash residue as a result of the 2014 Hazelwood brown coal mine fire contained in roof cavities of residences in Morwell. However, Senversa asked residents about any mould growing inside the houses they tested and made visual observations about mould. They found no link between brown coal ash residue and the growth of mould.

  • Should I be worried about ash that is accumulating on down-lights or other areas in my house? Could it be a fire hazard?

    According to Energy Safe Victoria, downlights pose a fire risk if they become covered by insulation or ceiling debris (including dust or ash residue).

    For more information refer to the factsheet on Energy Safe Victoria

  • I've heard about a similar project that is testing ash in the Latrobe Valley, what's the difference?

    Researchers at the Menzies Institute for Medical Research at the University of Tasmania are leading a small separate study of ceiling dust. They are looking at how far the smoke from the 2014 Hazelwood brown coal mine fire spread across the Latrobe Valley. In November and December 2015, the researchers collected dust and soil from 39 homes in the Latrobe Valley. Analysis of the ceiling dust samples has commenced and is due to be completed in 2017.

    For additional information please contact the research team at Latrobe.Dust@utas.edu.au or phone the ELF study helpline on 1800 322 102.

    The aim of the Ash residue in Morwell roof cavities project was to assess the potential exposure and risk of brown coal ash residue in roof cavities to the Morwell community as a result of the 2014 Hazelwood brown coal mine fire.

  • Does rainwater affect ash? Does it change its chemical structure?
    Rainwater would potentially aid in leaching and dissolution of metals and other chemicals from the ash into the soil or water it has landed on. Rainwater will also wash away and remove the ash from most structural surfaces where rainwater can penetrate. 
  • What does the ash look like?

    The literature review provided Senversa with a description of the physical appearance of the ash. The ash residue is lighter in colour than coal dust, is orange to orange brown and is fine to coarse grained.

    This was confirmed by Senversa’s visual observations in some roof cavities. Where it was observed, the ash residue was light in colour varying from white to pale orange. It typically appeared as a coarser-grained layer on top of finer-grained, darker dust beneath.

     
  • Is the chemical make-up of the ash known?

    Yes. Senversa undertook a literature review to understand the chemical make-up of the ash residue. Based on the results of the literature review (available on the department’s website), including analytical results for ash samples collected by EPA Victoria during the fire at the Hazelwood coal mine, the primary components of the ash are expected to be trace elements and metals. Many of these are likely to be present at concentrations similar to or lower than those present in natural soils.

    Elements which may be present at higher concentrations in ash than background soils include arsenic, antimony, barium, boron, lead, manganese, selenium, strontium, titanium and zinc. Polycyclic aromatic hydrocarbons (PAHs) are also formed during the burning process, and are reported to be present in ash samples, however below concentrations of potential concern for human health. Some other organic and inorganic compounds have also been identified in ash samples, however at very low concentrations that are below background levels in typical soils.

  • Is the ash different to what is in a furnace, wood burner or fireplace?

    Yes. The physical and chemical characteristics of ash in furnaces or fireplaces will depend on the material burned. Ash derived from wood or other organic materials will have different chemical composition and appearance than the ash from the brown coal mine fire.

  • Do different roof types let in more ash and dust than others?

    Yes. Several houses in Morwell have open slat eves which are likely to allow more dust into the roof cavity than sealed eaves. Tiled roofs, especially where the tiles are cracked or in a state of disrepair, allow more dust into the roof cavity due to the multiple joins where each separate tile connects. Metal roofs consist of large sheets of metal with fewer joins than tiled roofs, allowing less dust into the roof cavity. Reflective foil insulated roofs provide an additional barrier that may reduce dust load into the roof cavity.

  • What are the possible points of entry or modes of exposure to ash and dust inside the house?

    Points of entry for ash and dust from the roof cavity to the inside spaces of a house include, but are not limited to:

    • holes in the ceiling
    • cornices that are cracked or missing with visible gaps into the roof cavity
    • fans and vent points that are not sealed
    • gaps in ceiling roses
    • gaps in connections between flues and the ceiling.

    Ash and dust may also enter the house during renovation or maintenance activities that disturb ceilings or cavity walls, or that involve entry to the roof space.

    Senversa’s study suggested that dust and ash residue from the roof cavity was not a major contributor to dust in the living areas of the house. This is because the chemical make-up of roof cavity dust and ash was different to samples taken from inside the house.

  • Can you get filters to prevent dust getting into your home?

    The usefulness of filters for preventing or reducing the amount of dust entering your home from the roof cavity will depend on how the dust is entering. Dust may enter through a range of holes or gaps. Installing filters (e.g. in ducted heating or air conditioning vents) may reduce dust entry (if occurring) via your ducted system, however dust may still enter via other pathways.

  • The ash residue in/around my home was sticky, what could have caused it to be sticky like that?
    It is likely to be a product of the combustion of brown coal called char. Char is the solid material that remains after light gases (e.g. coal gas) and tar have been driven out or released from a carbonaceous material during the initial stage of combustion, which is known as carbonisation, charring, devolatilisation or pyrolysis.

Further frequently asked questions