Chemicals used in hydraulic fracturing

A flowchart showing the process of referral of HHRA from EPA to DoH
Figure 1 Referral process to Department of Health

Information on hydraulic fracture stimulation in Western Australia, including a description of chemicals used in hydraulic fracturing (external site) is provided by the Department of Mines, Industry Regulation and Safety.


The Western Australian Government established an Independent Scientific Panel Inquiry into hydraulic fracture stimulation in Western Australia in September 2017. The Panel produced a report (external site) in September 2018 containing 44 recommendations. The Government accepted all recommendations in principle and an Implementation Plan (external site) was released in July 2019. The implementation plan details how and when the government will action its policy decisions and the recommendations of the Inquiry.

In accordance with Recommendation 34 any proposal for hydraulic fracturing will be referred to the Environmental Protection Agency (EPA) (external site). A detailed and independently reviewed human health risk assessment that addresses potential health impacts from any chemicals used or produced is required for proposals within 2000 metres of a drinking water source or settlement. The EPA determines the level of review for each individual proposal and may only sometimes refer to other agencies for advice but the EPA has agreed to refer all proposals related to hydraulic fracturing to the Department of Health, Environmental Health Directorate (EHD) for review and advice.

Figure 1 shows the agreed referral process from the EPA to the EHD.

Drinking water protection

The risk of contaminating a drinking water reserve depends on the separation between the underground lateral directionally drilled fracture run projected to the centre of the earth and the underground (aquifer) or the surface water catchment area. The type, quantity and concentration of chemicals in fluids and the chemical by-products along with their properties are important considerations. More information is available here.

Chemicals not permitted to be used in hydraulic fracture stimulation

All chemicals proposed to be used in drilling and as ingredients in hydraulic fracture fluids are expected to be identified by the proponent. Any chemicals not registered or approved for use in Australia are not permitted to be used. The

regulate chemicals used in hydraulic fracturing and other applications.

The use of benzene, toluene, ethylbenzene and xylene (BTEX) as additives or ingredients in drilling and hydraulic fracture fluids is not permitted.

Public health assessments

The Department of Health provides information on how to undertake health risk assessments. The submitted health risk assessments are to include:

  • conceptual site model illustrating the sources-pathways-receptors identified as part of the exposure assessment
  • current material safety data sheets for any hazardous substances that may be in, or added to any fluids used for drilling or hydraulic fracturing or otherwise introduced into a well, reservoir or subsurface formation
  • tabularised inventory of chemicals proposed for use with evidence that chemicals are registered or approved for use in Australia.

Other relevant guidelines to be used in preparing the health risk assessment include:

Department of Health review of proposals

Following its review the Department of Health will provide advice to the EPA on public health risks from chemicals proposed to be used. The Department of Health will review each proposal with regard to:

  • chemicals proposed for use in drilling and hydraulic fracturing fluids
  • chemicals present or likely to be in produced or flow-back water
  • chemicals proposed for use in well testing and well maintenance
  • chemicals proposed for use in emergency scenarios
  • chemicals that proposed for use during closure and decommissioning of wells
  • chemicals in produced water and proposed for re-use for other purposes
  • airborne chemicals emitted (including volatile organic compounds (VOCs)) from activities, plant and equipment associated with hydraulic fracture stimulation.

The EPA will make the final assessment decision regarding the approval and use of the chemicals.

Register of chemicals used in hydraulic fracturing stimulating fluid

Once chemicals have been through the EPA assessment process they will be permitted to be used in Western Australia. The Department of Health has agreed to keep an up to date register (PDF 67KB) of these chemicals

Last reviewed: 06-09-2021