Australasian Science: Australia's authority on science since 1938

Hazelwood coal fire health impacts

The Victorian government may announce a partial evacuation of residents from the smoke-affected town of Morwell. Australian experts comment on the health impacts of coal fires.

"Coal smoke is very dangerous to health; we know this from some of the earliest epidemiological studies in this field on the London coal smoke smog of 1952 that killed around 12,000 people. This high number of deaths comes from a relatively low individual risk (around a 10 per cent increase in mortality during the London smog episode) applied to a large city population. So the more people who are exposed in Morwell, the greater the overall health problem will be. We would also expect emergency hospital admissions to rise, especially for respiratory conditions such as asthma and bronchitis. Those at greatest risk are children, the elderly and those with pre-existing chronic disease. Pregnant women would also be advised to keep away from the smoke. Staying indoors or wearing masks does not offer complete protection from some of the smoke particles, which can be tiny and easily penetrate inside homes. If I lived in the area I would move my family away until the fire was out."

Associate Professor Adrian Barnett is a Principal Research Fellow at the Queensland University of Technology

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“In case of fires, usually particulate matter is the biggest concern, and specifically the PM2.5 fraction (particles smaller than 2.5 microns). Their concentration in the air could be high, and above the WHO health guideline levels even if air pollution is not obvious. However, if smoke is seen, it normally means that the concentrations are very high. I understand some authorities yesterday were trying to calm the public by saying that so far the duration of the exposure (since the beginning of the fire) would classify it as ‘short term’, and therefore is not expected to cause problems. This is not true. The duration of the London smog incident in 1952 was about two weeks and caused so much mortality. The London fire duration is comparable to the Hazelwood fire. There are many examples of health impacts due to much shorter exposure to combustion products than this fire.”

Professor Lidia Morawska is a Professor in the School of Chemistry, Physics and Mechanical Engineering, Faculty of Science & Engineering at the Queensland University of Technology and the Director of the International Laboratory for Air Quality and Health (ILAQH) at QUT, which is a WHO Collaborating Centre on Air Quality and Health

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“This fire is difficult to extinguish because it is deep seated within the coal seam and the coal seam is very extensive both vertically and horizontally. The scale of the control process makes it difficult as well as complicated, due to the need to manage the water runoff, to prevent ancillary issues like flooding the operating mine or bogging the firefighting equipment. To control this fire, the heat must be removed from the coal and the air must be stopped from reaching the coal. This sounds simple in theory but in practice, given the scale of this event, it is not.

The potential hazards of such a fire are quite varied. The obvious ones relate to the particulate matter, especially the fine particle sub 2.5 microns in diameter, as these can cause acute respiratory effects. These fine particles are generated by combustion processes such as diesel vehicles and make up a component of urban smog such as what is coating Beijing at present. There is no absolute safe concentration for these particles as they can affect sensitive sectors of the population (eg the infirm, the young and the elderly) at very low concentrations. There is an advisory standard for this pollutant which currently is regularly being exceeded in Morwell. Other pollutants include carbon monoxide, oxides of nitrogen and oxides of sulphur. Potentially more worrying is the possibility of long term chronic health effects if the coal undergoes significant distillation and produces measurable quantities of hydrocarbons such as benzene, toluene and xylene, as well as the poly cyclic aromatic hydrocarbons. No doubt the EPA and the health department are monitoring for these.”

Professor David Cliff is a Professor of Occupational Health and Safety in Mining and Director of the Minerals Industry Safety and Health Centre at the University of Queensland

Source: Australian Science Media Centre