From 1 December 2026, PAH mixtures containing benzo[a]pyrene and coal tar pitch volatiles have no exposure limit at all, because Safe Work Australia treats them as cancer-causing chemicals with no safe threshold. The duty becomes eliminate, substitute, or reduce exposure as much as reasonably practicable. Bitumen fume keeps a limit, and it drops from 5 to 0.5 mg/m3 as an eight-hour average. Air monitoring still shows where exposure is and whether controls work, and Airsafe does it: samples are analysed by an external NATA-accredited laboratory; flow rates and air volumes are measured under Airsafe’s NATA accreditation, No. 2959.
What are PAHs, and which mixtures contain them?
Polycyclic aromatic hydrocarbons, usually called PAHs, are chemicals formed when organic material burns. In workplace air, they can be present in fumes, particles and mists from particular materials and processes.
Mixtures that contain PAHs include asphalt fumes and bitumen, coal tar, coal tar pitch volatiles, creosote, coke oven emissions, diesel and petrol exhaust particles, and mineral oil mists.
That is why PAHs turn up across quite different workplaces. The source may be a hot product, a combustion process, exhaust from diesel equipment, or contaminated material being disturbed during work.
Which work exposes people to PAHs?
The work activities that need special attention include asphalt road surfacing, tar roofing, coke plant work, aluminium primary plants, diesel emissions in industries such as automotive and mining, and contaminated land remediation.
A road crew, a roofing crew, a coke plant worker, a worker in an aluminium primary plant, a mechanic or a mining worker around diesel emissions, and a remediation worker on contaminated land may all be dealing with PAH exposure.
If diesel emissions are part of the issue at your site, diesel particulate monitoring may also be relevant, because diesel and petrol exhaust particles are listed among mixtures that contain PAHs.
What does “no exposure limit” mean in practice?
Having no exposure limit makes the duty stricter. The contaminant is still covered by the WHS Regulations, and a measured amount is never simply “acceptable”.
For these PAH mixtures and coal tar pitch volatiles, a monitoring result can no longer be compared with a numerical workplace exposure limit.
The duty is expressed in the source document this way: “eliminate them from the workplace, replace them with a safer alternative if possible, or reduce the risk as much as reasonably practicable.”
The Changes between the WES and WEL page also explains that these chemicals have been removed from the WEL list into a new list in recognition that they are non-threshold genotoxic carcinogens. The questions a regulator or a client will ask are what has been done to get exposure down as far as reasonably practicable, and what evidence shows it worked.
What is changing for bitumen fume?
Bitumen fume is different because it keeps a numerical limit. The current eight-hour time-weighted average is 5 mg/m3. From 1 December 2026, the workplace exposure limit is 0.5 mg/m3 as an eight-hour average.
The eight-hour average is the average airborne concentration over an eight-hour working day, for a five-day working week. That is still a number you can compare monitoring results against.
There is a practical overlap here. Bitumen and asphalt fume also contain PAHs, so road and roofing work may need to be looked at in both ways. The bitumen fume result can be compared with the new 0.5 mg/m3 limit, while the PAH part of the exposure has to be reduced as much as reasonably practicable.
What does monitoring do when there is no number?
Personal air monitoring measures what a worker actually breathes over the shift. The sample is taken in the breathing zone, which is the area close to the worker’s face where inhalation exposure is assessed.
When there is no exposure limit to compare against, monitoring still answers useful questions. It shows which tasks carry the exposure, which workers are getting the exposure, whether controls such as extraction, enclosure, work method, ventilation and respiratory protection are reducing it, and whether exposure is going down over time as controls change.
It is also useful before and after a change. If you alter ventilation, change the work method, enclose a process or change respiratory protection, monitoring can show whether that change reduced exposure. For a non-threshold contaminant, that evidence becomes part of showing what “as much as reasonably practicable” has achieved.
How does Airsafe do PAH and bitumen fume monitoring?
Airsafe does this as occupational hygiene work. A consultant sets up personal sampling in the worker’s breathing zone using a calibrated pump worn by the worker. The pump draws air through the appropriate sampling media while the work is being done.
For PAHs and bitumen fume, the sampling media is sent to an external NATA-accredited laboratory for analysis. Airsafe measures the flow rates and air volumes under our NATA accreditation, No. 2959. Our accreditation covers the measurement of the air volume sampled; the laboratory’s own NATA accreditation covers the analysis.
The consultant who did the job signs the report. If a client asks for Certified Occupational Hygienist sign-off, Philip Turner is Airsafe’s COH and signs the reports that need that level of review.
Airsafe is based in Sydney, and our consultants travel throughout Australia. We investigate, sample, monitor, assess and validate; we don’t remove or remediate.
For PAH and bitumen fume monitoring, call Airsafe on 1300 888 338.
Questions people ask
What are PAHs, and which jobs expose workers to them?
PAHs are polycyclic aromatic hydrocarbons formed during combustion of organic material. They can be present in asphalt fumes and bitumen, coal tar, coal tar pitch volatiles, creosote, coke oven emissions, diesel and petrol exhaust particles, and mineral oil mists. Work needing special attention includes asphalt road surfacing, tar roofing, coke plant work, aluminium primary plants, diesel emissions and contaminated land remediation.
Is there an exposure limit for bitumen fume in Australia?
Yes. Bitumen fume keeps an exposure limit after 1 December 2026. The eight-hour time-weighted average drops from 5 mg/m3 to 0.5 mg/m3. An eight-hour time-weighted average is the maximum average airborne concentration calculated over an eight-hour working day for a five-day working week.
Do I need air monitoring for asphalt, roofing or road work?
Air monitoring is the practical way to find out where exposure is occurring and whether controls are working. Asphalt fumes and bitumen can contain PAHs, and bitumen fume also has a numerical exposure limit. For asphalt road surfacing and tar roofing, monitoring can help show both the bitumen fume result and the PAH exposure pattern.
How do you measure PAH exposure when there’s no limit to compare against?
The sample is still taken from the worker’s breathing zone with a calibrated pump and appropriate sampling media. The result can no longer be judged against a PAH limit, but it still shows which tasks and workers carry exposure, whether controls are reducing it, and whether results fall after controls are changed.
What does “reduce as far as reasonably practicable” mean for PAHs?
For the listed PAH mixtures, the duty is to eliminate them from the workplace, replace them with a safer alternative if possible, or reduce the risk as much as reasonably practicable. Monitoring gives measured evidence of what controls have achieved, especially when comparing results before and after changes to work methods, ventilation or other controls.
Do coal tar products and creosote contain PAHs?
Yes. Coal tar, coal tar pitch volatiles and creosote are listed among mixtures that contain PAHs. Coal tar pitch volatiles are also one of the non-threshold genotoxic carcinogens that will no longer have a numerical exposure limit from 1 December 2026, so the focus is on eliminating, substituting or reducing exposure as far as reasonably practicable.
Do workers exposed to PAHs need health monitoring?
Yes, where the business decides there is a significant risk to the worker’s health from PAH exposure. Schedule 14 health monitoring for PAHs includes demographic, medical and occupational history, physical examination, personal exposure records and health advice. It is carried out by or under a registered medical practitioner. Airsafe does the air monitoring, not the medical side.
