Regulations 49–50: WHS Airborne Contaminants

Regulatory citation: Model Work Health and Safety Regulations, Chapter 3, Part 3.2, Division 7, Regulations 49–50 (Managing risks from airborne contaminants)

What Are the WHS Airborne Contaminant Regulations?

Regulations 49 and 50 of the model WHS Regulations deal with airborne contaminants, such as dusts, fumes, mists, gases and vapours. Regulation 49 requires PCBUs to ensure that no person at the workplace is exposed to a substance or mixture in an airborne concentration above its exposure standard. Regulation 50 sets out when air monitoring is required and how results must be kept.

The exposure standards are those in the Workplace Exposure Standards for Airborne Contaminants (WES) list published by Safe Work Australia. That list is being replaced by the Workplace Exposure Limits (WEL) list. Safe Work Australia says the WEL list applies from 1 December 2026, once implemented in the WHS laws of the Commonwealth, states and territories.

Why Exposure Standards Matter

Many airborne contaminants cause disease years after exposure, including lung disease, cancer and nervous system damage. Exposure standards set a legal ceiling. They are not a safe level for everyone, and the general duty to eliminate or minimise risk so far as is reasonably practicable still applies below the standard.

Core Obligations

1. Do Not Exceed the Exposure Standard (r49)

A PCBU at a workplace must ensure that no person at the workplace is exposed to a substance or mixture in an airborne concentration that exceeds the exposure standard for that substance or mixture. This applies to all people at the workplace, not only employees.

2. Manage Risk Below the Standard Too

Meeting the exposure standard does not end the duty. Under the model WHS Act and Part 3.1 of the regulations, risks must still be eliminated or minimised so far as is reasonably practicable using the hierarchy of control. Ventilation, substitution, enclosure and wet methods usually come before respirators.

3. Monitor When Unsure (r50(1)(a))

The PCBU must ensure air monitoring is carried out to determine the airborne concentration of a substance or mixture that has an exposure standard, if the person is not certain on reasonable grounds whether the concentration exceeds the exposure standard.

4. Monitor When Needed to Assess Health Risk (r50(1)(b))

Air monitoring is also required if monitoring is necessary to determine whether there is a risk to health. This can apply when processes change, new substances are introduced, or workers report symptoms.

5. Keep Monitoring Records for 30 Years (r50(2)(a))

The results of air monitoring must be recorded and kept for 30 years after the date the record is made. The long retention period reflects the long delay between exposure and many occupational diseases.

6. Make Results Accessible (r50(2)(b))

Monitoring results must be readily accessible to persons at the workplace who may be exposed to the substance or mixture. Workers should be able to see and understand the results for the work they do.

7. Prepare for Workplace Exposure Limits

Safe Work Australia has published a WEL list to replace the WES list from 1 December 2026, after a transition period ending on 30 November 2026. Most values are unchanged, but some have been reduced or increased, and some substances added or removed. Ministers asked for further impact analysis on the proposed changes for nine substances, including silica, benzene and formaldehyde. Until the change applies in your jurisdiction, the current WES values must be met.

Common Compliance Approaches

Prioritise With a Contaminant Inventory

List the substances used or generated, the tasks that release them, and their exposure standards, then rank where monitoring and controls are most needed.

Use a Competent Occupational Hygienist

Personal air sampling in the breathing zone, using recognised methods, gives results that can be compared with the exposure standard and defended if challenged.

Check WEL Changes Now

Compare your monitoring results against the new WEL values, especially those that have been reduced, so controls can be upgraded before the change applies.

Example: Airborne Contaminant Monitoring in Practice

A timber joinery business is unsure whether hardwood dust levels at its sanding stations exceed the exposure standard. It engages an occupational hygienist, who carries out personal air sampling over a full shift on three workers. One result is close to the standard, so the business upgrades extraction at that station and moves to vacuum cleaning instead of compressed air. The results are filed in its records system for 30 years, and a summary is posted on the lunchroom noticeboard. The business also checks the new WEL value for wood dust ahead of December 2026.

Related regulations: WHS hazardous chemicals, WHS personal protective equipment, WHS hierarchy of controls.

Note: This summary is based on the model WHS laws published by Safe Work Australia. The model laws only have legal effect once a jurisdiction adopts them. Most states and territories have adopted them with some variations, which can include different wording or regulation numbers, while Victoria has not adopted the model WHS laws and has its own OHS laws. Amendments to the model laws apply only once a jurisdiction adopts them. Always check the legislation and codes of practice that apply in your jurisdiction.

Frequently Asked Questions

Is air monitoring always required?

No. Under regulation 50, monitoring is required when the PCBU is not certain on reasonable grounds whether the exposure standard is exceeded, or when it is needed to determine whether there is a risk to health.

How long must air monitoring records be kept?

Results must be recorded and kept for 30 years after the record is made, and be readily accessible to people at the workplace who may be exposed.

When do workplace exposure limits replace exposure standards?

Safe Work Australia states the WEL list takes effect on 1 December 2026, after a harmonised transition period ending 30 November 2026. It applies once implemented in each jurisdiction's WHS laws.