| 📋 Article Summary — Chemical Risk Assessment in Australian Workplaces | |
|---|---|
| Key Fact 1 | Chemical risk assessments are legally required for all hazardous chemicals used in Australian workplaces under the WHS Regulations |
| Key Fact 2 | A risk assessment must consider the specific tasks, exposure duration, ventilation, and work practices — not just the SDS |
| Key Fact 3 | For complex or high-risk chemicals, a qualified occupational hygienist should conduct or review the risk assessment |
| Read Time | 10 min |
The Legal Requirement for Chemical Risk Assessment
Under Chapter 7 of the WHS Regulations 2017, PCBUs that use hazardous chemicals must manage the risks associated with those chemicals. Regulation 352 requires that the PCBU ensure a risk assessment is conducted if it is not certain that the risk from the chemical is minimised. While some low-risk chemicals may be managed effectively by following SDS guidance alone, any chemical with significant inhalation, skin absorption, or other exposure potential warrants a formal risk assessment. For workplaces handling corrosive substances, including strong acids and alkalis, our dedicated article on acids and alkalis hazard assessment and engineering controls provides substance-specific WES values and first aid guidance.
A chemical risk assessment is not a one-time tick-box exercise. It must be reviewed whenever there is a change in the chemical used, the task, the work environment, or new information about the hazard becomes available (including updated WES values under the WES to WEL transition). Records of risk assessments must be kept for at least 5 years.
Step 1: Hazard Identification — What Chemicals Are Present?
The starting point is a complete chemical inventory. This requires systematically identifying every hazardous chemical present at the workplace, including:
- Raw materials and process chemicals
- Products (coatings, adhesives, solvents, cleaning agents)
- By-products and reaction intermediates (thermal degradation products, chemical reactions between substances)
- Maintenance chemicals (lubricants, hydraulic fluids, rust inhibitors)
- Hazardous chemicals generated by processes (welding fume, diesel exhaust, wood dust)
For each chemical, gather the current SDS and note the GHS hazard classification, WES values (or relevant OELs), routes of exposure, and any carcinogen, reproductive toxin, or sensitiser classifications. Pay particular attention to chemicals with skin notation (Sk) as these require additional assessment beyond inhalation exposure.
Step 2: Exposure Assessment — Who Is Exposed, How Much, and How Often?
This is the most technically demanding step and the one where a qualified occupational hygienist adds the most value. Exposure assessment requires understanding:
- Job tasks and duration: Which tasks involve the chemical, how long each task takes, and how often it is performed
- Work environment: Ventilation (natural or mechanical), room volume, proximity to the source
- Routes of exposure: Inhalation (vapour, aerosol, mist, dust, fume), dermal absorption, ingestion
- Worker characteristics: Number of workers exposed, work rate (physical activity level), individual variability
Exposure estimation approaches range from simple (using the SDS and judgment), to intermediate (using validated tools such as the AIOH exposure banding tool or the COSHH essentials model), to definitive (actual air monitoring using personal sampling by a NATA-accredited occupational hygienist).
For chemicals with carcinogen status, sensitiser potential, or reproductive toxicity, actual air monitoring is strongly recommended over modelling alone. Modelling can significantly underestimate exposure in many real-world scenarios.
Step 3: Risk Evaluation — Compare Exposure to the WES
The WES (or WEL after December 2026) provides the benchmark for inhalation exposure. A monitoring result below 50% of the WES generally indicates adequate control. Results between 50% and 100% of the WES are a warning zone requiring action. Exceedances of the WES require immediate control improvements.
For carcinogens and sensitisers, the ALARP principle means that even WES compliance is not the end point — further reduction should be pursued if reasonably practicable. Document the ALARP decision-making process.
For dermal exposure, no equivalent numerical standard exists. Dermal risk must be assessed qualitatively or using biomonitoring where available. Key factors include: frequency and duration of skin contact, skin surface area contacted, concentration of the substance, skin-penetrating properties (Sk notation), and adequacy of current skin protection measures.
Step 4: Risk Control — Apply the Hierarchy
Controls must be selected and implemented in strict hierarchy order:
- Elimination: Remove the chemical entirely from the process
- Substitution: Replace with a less hazardous alternative
- Engineering controls: LEV, enclosed systems, process isolation, dilution ventilation
- Administrative controls: Safe work procedures, training, exposure time limits, job rotation
- PPE: Respiratory protection, gloves, protective clothing — only as a last resort or supplement to higher-order controls
A common error in chemical risk assessments is jumping straight to PPE (particularly respiratory protection) without adequately considering whether engineering controls could achieve adequate exposure reduction. PPE fails silently, degrades with use, and requires constant human compliance — it is always the least reliable control option.
Step 5: Review, Monitor, and Verify Controls
Risk assessment is a cycle, not a linear process. After implementing controls:
- Repeat air monitoring to verify that controls have achieved the intended reduction in exposure
- Review risk assessments whenever processes change, new chemicals are introduced, or monitoring results indicate inadequate control
- Review at least every 5 years even without changes
- Review after any incident (chemical spill, overexposure, near miss) involving the assessed chemical
Control verification monitoring (re-sampling after installing new LEV or changing work processes) is a critical but often overlooked step. Installing controls without verifying their effectiveness is analogous to taking medication without confirming the dose is therapeutic.
Frequently Asked Questions
Can I use a generic risk assessment template for all chemicals?
A common template is useful for structure and consistency, but the actual risk assessment must be specific to each chemical in the context of actual use conditions at your workplace. A generic template that is not tailored to the specific chemical, task, and workplace will not meet the legal requirement and will not effectively identify or control the relevant risks.
Do I need a separate risk assessment for each chemical product?
Not necessarily. Similar chemicals used in similar tasks can be grouped — for example, a single risk assessment covering “glycol ether-based cleaning solvents used in the degreasing bay” may cover several products with similar hazard profiles and identical use conditions. However, if chemicals have significantly different hazard profiles, exposure levels, or tasks, they should be assessed separately.