Consultation on a proposed workplace exposure standard for diesel particulate matter

Overview

Safe Work Australia is seeking stakeholder feedback on a proposed workplace exposure standard (WES) for the diesel particulate matter (DPM) component of diesel engine emissions (DEE).

The proposed WES for DPM is specified in terms of the respirable elemental carbon (REC) content of the DPM. The proposed WES is an eight-hour time weighted average (TWA) of 15 micrograms of REC per cubic metre (i.e. 15 μg REC/m3).

Background

DEE is a complex mixture of hundreds of chemicals, in gas and particulate forms, found in the exhaust emissions from diesel engines. DPM refers to the particles within DEE. The quantities of chemicals within the DEE mixture differ depending on a variety of factors, including engine type, operating conditions, fuel, lubricating oil, and whether an emission control system is present. Research has shown that prolonged exposure to DEE can lead to lung irritation, which can progress to an inflammatory response and lung cancer. Exposure to DEE may also be linked to an increased risk of bladder cancer.

Under the model Work Health and Safety (WHS) Act, a person conducting a business or undertaking (PCBU) has a duty to ensure, so far as is reasonably practicable, the health and safety of workers and others at the workplace (section 19). This requires PCBUs to eliminate risks to health and safety, so far as is reasonably practicable; and if this is not reasonably practicable, to minimise those risks so far as is reasonably practicable (section 17).

Under the model WHS Regulations, a PCBU must ensure that no person at the workplace is exposed to a substance or mixture in an airborne concentration that exceeds the WES for that substance or mixture. The WES are set out in the Workplace exposure standards for airborne contaminants (WES list). The WES list does not currently include an exposure standard for DEE or DPM.

As part of the recent WES review, WHS ministers agreed that DEE, along with other chemicals, should be considered for inclusion in the WES list. However, the initial evaluation for DEE indicated a further review would be needed in order to establish a WES. On consideration of the initial evaluation report and the feedback received from public consultation, Safe Work Australia Members agreed that a further review was needed.

Safe Work Australia subsequently engaged SLR Consulting Australia Pty Ltd to review the available literature to determine the potential for a DEE WES.

Review findings

The review found that there was insufficient information to recommend a WES for DEE itself, because the variability in DEE composition can result in varied health related responses. However, there was sufficient evidence to recommend a WES for DPM based on measuring REC.

The expert review report included the following recommendations to protect workers from the risks of developing DEE-related diseases:

a TWA of 15 µg REC/m3 for DPM from any type of diesel engine, and

the proposed TWA is to be applied in conjunction with the WES for other components of DEE, such as nitrogen dioxide, to ensure the risk of health effects from the mixture as a whole are adequately controlled.

Purpose of the consultation

The purpose of this consultation is to gather feedback and evidence to assist Safe Work Australia Members in their consideration of whether to recommend to WHS ministers that a WES for DPM is introduced in the model WHS Regulations.

Some jurisdictions may already have a WES for DEE or DPM in their mining work health and safety laws. Mining stakeholders are strongly encouraged to seek advice from their mining regulator regarding the relevance of the proposed WES in their jurisdiction before responding to this consultation.

Submissions from all stakeholders with an interest in a WES for DEE are welcome. To assist with making a submission, several targeted questions are provided for stakeholders to consider. There is no requirement to answer all of the consultation questions.