The Australian Government commissioned the National assessment of chemicals associated with coal seam gas extraction in Australia in 2012.
The Assessment examined 113 chemicals used by companies in Australia between 2010 and 2012 in drilling and hydraulic fracturing for coal seam gas, to develop a stronger understanding of the risks these chemicals could pose to the health of workers, the public and the environment.
Read the Assessment Overview for a summary of the Assessment and its methods and findings.
The Assessment was a complex project of Australian Government partners, resulting in 14 reports and reviews.
What the Assessment looked at
The Department undertook the environmental risk assessment using two methods. The method used was based on the level of information that was available for the chemical.
For chemicals with only basic information available, the risk assessment was done by compiling evidence from the international scientific literature to support an expert judgement on the chemical’s potential to harm the environment. This approach considered the behaviour of the chemicals in the environment and what harm they could cause to water- and land-based animals and plants. It also considered how chemicals were used in coal seam gas extraction, factoring in the most likely ways for chemicals to be released during the extraction process and protective measures to prevent and limit spills and leaks.
Chemicals with more information available were assessed using a different method. Scenarios were developed to show how chemicals might enter a water body such as a river, pond or lake. Potential harm to the environment was assessed by determining what effect the chemicals could have on aquatic organisms in the water body, including algae, invertebrates and fish. As with the human health risk assessment, the scenarios were informed by the scientific literature and the industry survey in the preparatory steps.
The risks to the environment were assessed for the following scenarios:
- a chemical spills during transport from a storage warehouse to the well site and the spill is not detected, notified or cleaned up
- a chemical spills from storage at a storage facility and the spill is not detected, notified or cleaned up
- a chemical spills from storage at the well site and the spill is not detected, notified or cleaned up
- a chemical spills during use and handling at the well site and the spill is not detected, notified or cleaned up
- waste water containing a chemical spills during use or management of the waste water and the spill is not detected, notified or cleaned up
- waste water containing a chemical leaks from storage pond or tank and the leak is unreported
- waste water containing a chemical is reused for dust suppression
- waste water containing a chemical is reused for irrigation.
Scenarios where coal seam gas chemicals could enter the environment
Text alternative of the scenarios infographic
Where an industrial spill or leak does occur, companies are required to have protocols in place to promptly detect, control and report the incident. The use and management of coal seam gas waste water is also subject to strict conditions and controls.
What the Assessment found
The Assessment looked at what could happen if a chemical entered the environment through accidental spills and leaks, or intentional reuse of untreated coal seam gas waste water for other purposes.
The majority of chemicals (61 of the 113 chemicals tested) were found to be unlikely to cause harm to the environment when used in coal seam gas extraction, even if they were to spill or leak in high volumes.
It is in the event of a transport spill or where untreated waste water containing chemicals is reused for irrigation or dust suppression, that certain chemicals have the potential to cause harm to the environment.
Scenarios where chemicals could potentially cause harm to the environment
Some coal seam gas chemicals could potentially cause harm to the environment, primarily in the event of a transport spill or where waste water is reused for irrigation or dust suppression.
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Spill during transport to the well site |
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| When the chemical could enter the environment | What chemicals could cause harm | What protects the environment from harm |
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A transport accident occurs, resulting in a large spill of a chemical into a nearby water body. Under this scenario, a truck-load (up to 14,000 L) of the chemical would have to spill into surface water, the spill would have to go undetected, and no action would have to be taken to prevent or clean up the spill. |
If no protective measures were in place, 15 of the 113 chemicals tested could potentially cause harm to the environment in the event of a transport spill. These chemicals are:
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This scenario looked at what could happen if standard precautions to prevent or control the spill were not taken. In practice, the transport and use of industrial chemicals is regulated by the states and Commonwealth. Legislation, regulations and national standards set out the requirements for the safe transport of chemicals, including for packaging, driver training, safety equipment and vehicle standards. These measures reduce the risk of a spill occurring, or of not being detected and cleaned up if it does occur. Coal seam gas projects also operate under conditions of approval. State and Commonwealth regulations and industry codes of practice require companies to manage chemicals in a way that minimises the risk of causing harm, which includes how they handle and transport chemicals. Companies must also have emergency protocols in place to detect and respond to spills, including containing, cleaning up and reporting the spill. |
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Reuse of waste water for dust suppression |
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Reuse of waste water for irrigation |
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| When the chemical could enter the environment | What chemicals could cause harm | What protects the environment from harm |
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Waste water from coal seam gas extraction is reused on land for dust suppression or irrigation. Under this scenario, the waste water would have to contain large concentrations of a chemical and be applied repeatedly to land that receives low rainfall. |
Four of the 113 chemicals tested could potentially cause harm to the environment when waste water containing the chemicals is reused. These chemicals are:
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Conditions of coal seam gas approvals under state and Commonwealth law, together with state water legislation and policies, govern how waste water can be reused what quality standards it must meet before use. |
Where detailed information was unavailable the chemicals could only be assessed at the earliest, most conservative level of testing which was designed to overestimate risk. The chemicals were classed as potentially harmful at this level, but further information and testing would be required to determine the actual level of risk.
What protects the environment
These scenarios looked at what could happen if standard safety and handling practices were not in place. Industrial chemical use and coal seam gas operations are closely regulated by state, territory and Commonwealth governments, which legally require protective measures to be in place to safeguard human health and the environment.
Legislation, regulations, standards and codes of practice cover the coal seam gas industry including workplace and public health and safety, environmental and water protection, managing and reusing waste water, and the transport, handling, storage and disposal of chemicals. Coal seam gas projects must be assessed and approved under state, territory and Commonwealth environmental laws and may be subject to site-specific conditions including how the companies manage chemical risk.
More information
What the findings mean for:
Information about:
Text alternative of the infographics
Scenarios where coal seam gas chemicals could enter the environment
Relates to storage of chemicals
- Leak from storage at an intermediate facility
- Leak from storage at the well site
Relates to transport of chemicals
- Spill during transport to the well site
Relates to use at the well site
- Spill during use at the well site
Relates to management of waste water
- Spill during management of waste water
- Spill during storage of waste water
- Reuse of waste water for dust suppression
- Reuse of waste water for irrigation