For over 40 years, the Australian Institute of Petroleum sponsored the development and operation of an independent epidemiology program called Health Watch.
Health Watch was a university-based research program which studied people who have worked in the Australian petroleum industry to find out what happened to them in terms of their health. Since 1980, Health Watch tracked over 20,000 past and present employees during their time in the industry and after they left or retired. Along the way, Health Watch recorded any occurrence of cancer and, eventually, the cause of death.
By comparing this information for different jobs within the petroleum industry and with the general Australian population, Health Watch provided highly valuable information about risks in jobs in the petroleum industry and risks from lifestyle factors. The information from the Health Watch study has been important in identifying factors that may be a risk to health and ways in which these risks may be controlled.
Latest Health Watch Reports
The latest Health Watch report, the 16th, presents the findings in detail. Also available are the 15th, 14th, 13th, 12th and 11th Health Watch Reports and the Health Watch Case Control Report (called the Lympho-haematopoietic Cancer and Exposure to Benzene in the Australian Petroleum Industry, Technical Report and Appendices).
The Health Watch Study was always conducted independently, first at the University of Melbourne and then, from 1998, at the University of Adelaide. In 2005 the study was transferred to the Monash Centre for Occupational and Environmental Health, a leading international centre for epidemiological programs and collaborative research at Monash University.
Participation in the study
Health Watch covered those petroleum industry employees from all major oil and gas companies who voluntarily joined the program at their work sites across Australia. Although participation in Health Watch was voluntary, the employee participation rate was typically outstanding – clearly demonstrating the value of the Study to employees. Historically, about 95% of the industry's employees who were approached to participate have joined Health Watch (including employees from refineries, distribution terminals, and production sites onshore and offshore) during major recruitment drives between 1980 and 2000. The study has enjoyed very strong support from employees, unions and companies and is also very well regarded and respected internationally.
Employees in the industry were enrolled in the study by participating in one or more of five industry surveys since the 1980s (including a recent survey over 2010–12), using a detailed job and health questionnaire. This process obtained information on job tasks, on lifestyle factors (e.g. smoking and alcohol) and on health status. An employee was taken into the cohort analysis following a survey questionnaire or after having served five years in the industry, whichever is later, and remained in the Health Watch cohort for life. Employees have been contacted periodically for an update of their employment and health status.
Design of the Study
The main output of the study was an analysis of mortality and cancer incidence. These were carried out by comparing the rates of deaths and cancers in the Health Watch cohort with the rates in the age and sex matched general Australian population and within the cohort.
The Australian Institute of Health and Welfare (AIHW) compiles data for the National Death Index (NDI) and the Australian Cancer Database (ACD) on behalf of all State Death and Cancer Registries. Deaths and cancers for past and present employees in Health Watch were obtained by linking the Health Watch data (obtained when Monash conducted an employee questionnaire or survey) with the data from the Registries.
Results were published in periodic Health Watch reports (of which the latest and last report is the 16th) and in scientific medical journals. A summary of the latest Report findings are also sent to individual Health Watch members (see Employee Infosheet below).
What Did Health Watch Find?
Overall, the Study clearly shows that petroleum industry employees have better health than the general Australian community and are less likely to die from cancer and from heart, respiratory and digestive diseases than the general population.
Compared with the general Australian population, the death rate in the Health Watch cohort was about 20% lower for men and 30% lower for women compared to the national rates, and lower for men in most major disease categories: heart disease (27% lower), cancer (10% lower), respiratory disease (27% lower), diseases of the digestive system (29% lower) and external causes such as accidents (29% lower).
The death rates for heart disease, stroke, respiratory and digestive diseases and other causes (eg. accidents, violence) were significantly lower than the comparable Australian rates.
There was a similarly significantly reduced chance of dying no matter where Health Watch members worked including upstream production sites, refineries, terminals and airports.
There was a reduced chance of dying from heart disease at the various workplace types.
The overall cancer rate of employees in the petroleum industry is no different to the overall cancer rate for the general Australian population.
Leukaemia has been a cancer of special concern in this industry because of its association with benzene exposure.
Earlier Health Watch reports indicated a higher-than-expected number of leukaemia cases. However, more recent reports including the analysis in the latest report confirms that the risk of leukaemia is now lower than that of the general population and has been reducing. One leukaemia type known to be associated with benzene exposure is Acute Myeloid Leukaemia (AML). There are 24 cases of this type of leukaemia in the Health Watch cohort, but this is lower than the 32 cases which would be expected, based on rates in the Australian population.
The industry has taken significant steps to reduce exposure to petroleum products in general and to benzene in particular. The known association between benzene and certain leukaemias has seen the Governments around the world set occupational exposure standards for benzene and petroleum companies have taken steps to make sure that they comply with them.
There have been 63 cases of mesothelioma diagnosed among Health Watch members. This cancer is strongly associated with asbestos exposure. It can take 30–40 years between exposure to asbestos and mesothelioma diagnosis.
As with benzene exposures, a greater awareness of the hazards of asbestos mean that working in the petroleum industry in more recent decades, is unlikely to result in asbestos exposure. This is highlighted in the recent Health Watch report by the significantly low lung cancer rates in men in the petroleum industry compared to the general population (16% lower than national rates).
Some overseas studies suggest higher rates of lung cancer in refinery maintenance workers can be due to such workers being exposed to asbestos, such as through asbestos lagging on pipes. In Health Watch there was no difference in lung cancer rates among refinery workers compared with those from all other workplaces and no difference in lung cancer rates between maintenance and non-maintenance refinery workers. This suggests that few asbestos-related lung cancers in Australian refinery workers are likely according to Monash University.
Compared to the general Australian population, Health Watch results (particularly for men) also show:
- lower rates of cancer of the liver, pancreas lip, oral cavity and pharynx;
- the same overall chance as the general population of developing cancer, which includes for men kidney cancer, bladder cancer (which previously had an elevated risk), and cancers of the stomach, colon, rectum and brain;
- a higher rate of melanomas was diagnosed in workers in the petroleum industry; this could be a result of more screening. The death rate from melanoma in the petroleum industry is similar to the national rates, it is possible that early diagnosis and treatment increased the survival rate. Importantly, the melanoma rate does not increase with increasing duration of employment, time since first employment or time period of first employment, which suggests that workplace factors are not a likely explanation.
- prostate cancer is the most common cancer in men in the Health Watch cohort (1371 cases) and there are more than the expected number of cases of prostate cancer in Health Watch compared to the national rates; however, deaths from prostate cancer in the Health Watch cohort are at the same rate as that of the general population; according to Monash University, “The increased incidence of prostate cancer, and the absence of an increased prostate cancer mortality, suggest a higher rate of screening compared to the general population”;
- No workplace type had a significantly increased risk of cancer
Effects of lifestyle
Health Watch results show that smoking has a powerful effect on the risk of early death, and that quitting smoking noticeably reduces the risks. The death rate from all causes increases significantly the more cigarettes smoked.
Combining all causes of death, it is estimated that smoking has played a part in about 1,470, or 43% of the 3,419 deaths among smokers in Health Watch.
For those who have low to moderate alcohol consumption (1-7 drinks a week), the overall death rate appears to be lower compared with those who don't drink at all. Heavy drinking (more than 5 drinks per day) is associated with a higher death rate (54% higher).
Why did Health Watch Close?
Health Watch followed the health of petroleum industry workers for over 40 years (since 1980) and there has been little major change in the findings, over the past five years since the last report in 2018. Health Watch was therefore no longer providing new scientific information for the industry and its employees. The very longstanding and independent conduct of the Study and its strong international reputation provides well-based confidence in its published analysis and results over its extended investigation period.
The AIP and Monash University would like to thank the Petroleum industry which has supported the Study and the cohort members for their enthusiastic participation.
Health Watch Frequently Asked Questions
Responses to many of the questions frequently asked by the community, employees and other stakeholders in relation to the Health Watch study are provided in the following document:
Latest Health Watch Reports
The latest Health Watch reports provide the analysis and findings in more detail. Available are the 16th, 15th, 14th, 13th, 12th and 11th Health Watch Reports and the Health Watch Case Control Report (called the Lympho-haematopoietic Cancer and Exposure to Benzene in the Australian…