Pinjarra Air Quality

In line with the requirements of Ministerial Statement 646, Alcoa prepared and is implementing an Air Quality Management Plan that details the approach to the monitoring and management of emissions to air from the Pinjarra refinery.The Air Quality Management Plan includes:

• monitoring methods, quality assurance/quality control procedures and sampling frequency for monitoring particulate emissions (including ultrafine particles) and metal emissions from the residue storage area (RSA) and stockpile area
• an assessment of cumulative particulate emissions taking into account background levels and levels from refinery sources
• sampling locations, methods (including continuous monitoring or campaign monitoring using continuous techniques) and quality assurance/quality control procedures.

Read Ministerial statement 646.

Licence L5271/1983/14 issued under Part V of the EP Act regulates emissions and discharges from bauxite (alumina) refining and associated activities and complements the requirements of MS 646.

A copy of the current version of licence L5271/1983/14 and records of decision making on recent amendments to the licence are published on the department's website.

The licence requires Alcoa to implement dust control measures and routinely undertake maintenance and housekeeping to minimise the generation of airborne dust from the bauxite stockpiles and the Residue Storage Area (RSA). The licence also requires Alcoa to take specific measures to control the risk of dust generation from oxalate storage.

Alcoa is required to operate three ambient dust monitors at locations to the west, north and south of the RSA. Monitoring data is required to be reported to the department annually and Alcoa is also required to report to the department within two working days if the 24-hour average total for suspended particulates (airborne particles or dust) exceeds 260 µg/m³ at any of the three ambient locations. Alcoa has not reported any exceedances of the 24-hour average at these monitors in the past three calendar year reporting periods.

The licence has been amended several times since 2016, including to:

• update conditions relating to the reuse of hydrocarbon waste oil and align regulatory requirements with those on licences for Alcoa’s Wagerup and Kwinana refineries
• authorise the construction and operation of the residue filtration facility within the RSA
• amend conditions for the residue filtration facility to reflect design changes
• authorise the construction and operation of an emergency spillway within the RSA in response to Alcoa’s audits against Australian and International guidelines for tailings dams. 

Alcoa also holds two active works approvals for works being undertaken at the Pinjarra refinery:

• Works approval W4661/2010/1 for works associated with the conversion of the existing wet RSA 1 to a dry stacked RSA. This works approval has been extended and amended on several occasions to account for project changes.
• Works approval W6393/2020/1 for the construction of a third bioreactor unit at the existing Oxalate Bio-removal Facility.

Several health studies have been undertaken to assess potential health risks associated with dust from alumina RSA’s, including dust studies in Pinjarra and at other Alcoa RSAs in Western Australia. The information obtained from these studies indicates that there is no significant public health risk posed by the dust. Nevertheless, the conditions of the Ministerial Statement and Part V Licence require controls to manage and minimise dust emissions from the premises.

The licence for the Pinjarra refinery requires Alcoa to implement a groundwater monitoring program, specifying sampling and analysis methodologies.

Portions of the Pinjarra refinery are also classified under the Contaminated Sites Act 2003 as possibly contaminated – investigation required.  The department is communicating with Alcoa regarding the further investigations necessary to address the classification.

Compliance inspections in 2017 and 2020 did not identify non-compliances with licence conditions. The requirements of MS646 were audited in December 2019 and no non-compliances were found in relation to dust emissions.

Following an increase in complaints about dust in 2021 and 2022, the department conducted a targeted inspection in June 2022 which focused on dust control measures at the refinery. The inspection determined that adequate dust control measures were being implemented at the refinery and that Alcoa was complying with its licence conditions relating to dust control.

Alcoa has a dust management plan in place.

Dust

In September 2022, the department met with the Shire of Murray regarding complaints of dust received by both organisations. The department will continue to work collaboratively with the Shire, the community and other relevant government agencies to investigate the concerns raised.

Between December 2021 and June 2022, the department collected dust and soil samples from the Pinjarra area, including samples from properties where residents had reported dust impacts which they have attributed the Alcoa operations. The department submitted these samples to an independent NATA accredited laboratory for analysis. The results were reviewed by the Department of Health which advised that the dust composition results did not indicate a health risk.

The Department of Health recommended further assessment of airborne dust be undertaken to gather further data. The department has completed a procurement process for the air monitoring recommended by the Department of Health, and has contracted these services to an independent air quality monitoring provider. 

The targeted air quality monitoring over five months in 2023 and 2024 to establish a seasonal baseline is now complete. The Ambient dust monitoring campaign, Pinjarra report and findings is available.  

The monitoring found that the levels of dust in the air were below relevant national guidelines. There were, however, smoke events from nearby fires that caused a higher level of fine particles on two occasions. The concentration of metals in airborne dust was also measured and found to be lower than health guidelines. 

The Department of Health has reviewed the results of the monitoring and advised that the measured concentrations of dust and metals do not represent a public health risk at the location where the monitoring was conducted.

The department is undertaking further air quality monitoring from 1 November 2024 to 30 April 2025 at a location in central Pinjarra to better characterise the levels of dust for the greater Pinjarra community.

The objectives of the monitoring campaign are to:

• measure the levels of airborne particles (PM₁₀ and PM_2.5) and the metals and silica content of PM₁₀ samples within the central Pinjarra area and compare these levels with air quality guidelines
• measure the levels of deposited dust within the central Pinjarra area and at a background site and compare these levels to evaluate relative amenity impact
• measure gaseous air pollutants (carbon monoxide – CO, nitrogen dioxide – NO₂, sulfur dioxide – SO₂, ozone – O₃) within the central Pinjarra area and compare these levels with air quality guidelines.

Monitoring results are available on the department’s air quality index (AQI) webpage, with data updated hourly. A report summarising the results will be published following conclusion of the monitoring and review by the Department of Health.

Following the campaign report, the department is planning follow-up information sessions to provide information on the monitoring and its results and to provide an opportunity for the community to engage directly with the department on this matter.

Licence review

The department has initiated a review of the Pinjarra Refinery licence to ensure it is fit for purpose, accurately reflects the current operational requirements, and is aligned with the department's risk-based Regulatory Framework. Read the licence review framework.

To inform the review, the department undertook public consultation between 9 December 2022 and 30 January 2023, which was advertised on the department's website, and registered stakeholders were contacted for their comments. The department thanks all those who made a submission; these will be taken into consideration through the review process. Any queries on the review process should be directed to info@dwer.wa.gov.au and quote L5271/1983/14.

The department will continue to investigate dust complaints relating to Alcoa’s Pinjarra Refinery. Anyone who is affected by dust in the area should report this to the department's Environment Watch Hotline on 1300 784 782 or use the form on the Environment Watch webpage.

Refinery expansion proposal under Part IV

The Environmental Protection Authority (EPA) is currently assessing Alcoa’s proposal to increase production at the Pinjarra refinery and increase the rate of bauxite mining at the existing Huntly Mine. Read more about this proposal and the status of the assessment.

New referrals under Part IV

The EPA published two referrals concerning Alcoa’s mining operations for a 7-day public comment period. These third-party referrals related to Alcoa’s approved and proposed mining operations in the Darling Ranges between 2022–26 and 2023–27. This public comment period closed on 15 August 2023. The EPA is now considering submissions and will make a determination on whether to assess the proposals, and if so, the level of assessment. Further advice and information may be sought by the EPA as part of this process. 

New works approval applications under Part V

In March 2023 Alcoa submitted a works approval application relating to a new RSA to be constructed within a corridor between two existing RSAs.

In June 2023 Alcoa submitted a works approval application relating to construction of a second Residue Filtration Plant at the location of the RSAs. Both applications have been advertised and published on the department's website for public comment, and registered stakeholders have been notified directly. The comment period for both applications has now closed. The department thanks all those who made a submission; these will be taken into consideration during the department's assessment of each application. Registered stakeholders will be notified when a decision is made on the relevant application they have provided comment on. 

The department will update this page as new information comes to hand.

If you have any questions related to this information, please email info@dwer.wa.gov.au.