Cause of Health Effects
Professor Campbell advised the Board that the potential for adverse health effects from exposure to smoke and ash depends on the:
- size of the fire
- effects of heat on combustion
- wind direction and speed
- time of day
- ambient temperature
- nature of the plume
- creation of photochemical smog.55
As detailed in Chapter 4.1 Health and wellbeing – background, there were a number of emissions produced during the Hazelwood mine fire that had the potential to cause short-term and long-term adverse health effects.
DURATION AND LEVEL OF EXPOSURE
The Hazelwood mine fire emitted smoke and ash for 45 days. The duration of the community’s exposure to smoke and ash is important as it provides an indication to public health officials and the general public about the potential for adverse health effects to occur.
In her statement to the Board, Dr Lester submitted that short-term exposure is generally considered to be from days to weeks, whereas long-term exposure is generally considered to be one year or more.56 In contrast, Professor Campbell advised that the most widely accepted definition of short-term exposure was exposure for a maximum of 48 hours.57 Evidently, there is some debate about the precise time periods used to define short-term and long-term exposure.
Dr Lester accepted that the duration of the community’s exposure to pollutants due to the Hazelwood mine fire did not fit comfortably into either category of exposure.58 In her statement she commented that:
… whilst the short term health effects of short term exposure, and the long term health effects of long term exposure, to smoke are well understood, DH [Department of Health] has identified that there is a gap in medical understanding of the long term health effects from exposure to smoke for a period similar in length to the Hazelwood Coal Mine Fire.59
Independent expert Ms Claire Richardson, Managing Director and Principal Consultant, Air Noise Environment Pty Ltd, agreed with Dr Lester that the majority of published studies consider health impacts in terms of short-term exposure and long-term exposure to pollution.60 There is a lack of academic research about exposure to a coal mine fire and the effects of exposure for the duration seen during the Hazelwood mine fire.61
A further issue is the inconsistency of the level of exposure suffered during the 45 days. Dr Lester advised that the air quality was variable throughout the duration of the mine fire.62 Ms Richardson highlighted that the uniqueness of the event was not only the duration but also that the exposure was not constant and that there were periods of short-term exposure to high concentrations of pollutants.63
Professor Campbell aptly described the situation facing the Department of Health in assessing health risks:
This started as a bushfire but very quickly became a hazardous materials fire in an industrial setting that was of prolonged duration and of intermittent high intensity, and the literature that you go to, to find out what to do, doesn’t exist. There is no literature to tell you about this phenomenon, and these exposures are coming in peaks.64
Accordingly, it was not only the unusual duration of the event, but also the varying exposure levels during the fire, that added to the complex task of determining the potential short and long-term adverse health effects to the community.
IRRITANT EFFECTS OF SMOKE
As anticipated, a number of community members experienced symptoms such as itchy eyes, sore throat, runny nose and coughing. Dr Lester stated that these symptoms are consistent with smoke irritation.65 She also stated that healthy adults usually find that where the exposure to smoke is short-term, these symptoms usually clear up once from the person is away from the smoke.66 Dr Brook told the Board: ‘of course we recognise that people are going to face short-term irritation, sore nose, sore eyes, blood noses, dizziness, headache, all very classic symptoms of smoke exposure.’67
Professor Campbell agreed that fine particles and larger particles can cause irritation to the eyes and mucous membranes.68 He advised the Board that whilst he was unable to comment on any specific individual, it is likely that the immediate health effects experienced by affected communities were due to the noxious fumes that residents were exposed to during the fire.69 Dr Paul Torre, Science Officer at the EPA, was of the same opinion and stated that at very high concentrations of PM2.5, people can suffer temporary symptoms such as sore eyes, throat and irritated nose, a dry or productive cough, tightness in the chest and shortness of breath.70
In addition to the short-term irritant effects, Dr Lester told the Board that she was concerned that the particulate matter could exacerbate cardiovascular and respiratory disease.71
PRESENCE OF CARBON MONOXIDE
Dr Lester told the Board that data provided to the Department of Health about the levels of carbon monoxide in Morwell did not indicate any potential risks to public health.72 She stated that carbon monoxide exposure is of greater concern in confined spaces and very close to the mine, and that the Department of Health was not anticipating that carbon monoxide would be a risk to the community as it dissipates very quickly.73
The Department of Education and Early Childhood Development (DEECD) received a report from Goodstart Early Learning Centre that children were exhibiting symptoms of hyperactivity, headaches, flushed faces and longer sleep times.74 The Department sought advice from Dr Lester, who replied in an email on 18 February 2014, that the symptoms were consistent with exposure to smoke.75 Professor Campbell agreed that such symptoms are consistent with exposure to smoke.76
ACQUIRED HEALTH CONDITIONS
The Board heard from a small number of individuals who developed new respiratory conditions as a result of exposure to smoke from the mine fire. For example, a local resident, who had not been previously diagnosed with asthma, suffered a severe asthma attack, which resulted in admission to hospital. Another local resident with no pre-existing respiratory illness was diagnosed with ‘irritant induced asthma’ and ‘reactive airways dysfunction syndrome’77 as a result of exposure to smoke and ash from the Hazelwood mine fire.78
Professor Campbell advised the Board that exposure to ozone and PM2.5 can induce asthma.79 Further, recent studies have demonstrated a link between ozone and new asthma in children. If children are exposed to insults (such as ozone) at critical periods during development, the development of the lungs can be arrested and in turn this could trigger asthma.80
RAPID HEALTH RISK ASSESSMENT
On 28 February 2014 the Department of Health commissioned the Monash University School of Public Health and Preventative Medicine to undertake a Rapid Health Risk Assessment to provide information about the short-term health effects of the Hazelwood mine fire on the local community. The study, submitted to the Department on 12 March 2014, found that:
- No additional deaths would be expected even if the level of exposure to the measured level of air quality continued for six weeks (using the air quality level at the average exposure in Morwell during the fire – the actual exposure level used was not detailed).
- The principal risks to the health of the Morwell community from the Hazelwood mine fire were fine particles and carbon monoxide.
- There does not appear to be any significant risk from sulphur dioxide.
- The risk from exposure to other air toxic hazards is currently unknown.
- If the fine particles levels remained in the extreme range (over 250 µg/m3) for three months this may result in additional deaths in the community.81
Dr Lester advised that the study concluded that the level of exposure to smoke and ash experienced by the community in Morwell would not be expected to cause any additional deaths because the level of smoke did not extend for longer than six weeks.82 However, the study was based on a standard Victorian population and was not adjusted for the poorer health status found in Morwell.83