Carcinogens in the Workplace: How Australian Law Treats Substances Without a Safe Threshold

The Scale of Occupational Cancer in Australia

Occupational cancer is the single largest cause of work-related death in Australia. Safe Work Australia’s estimates suggest approximately 5,000–6,000 cancer deaths per year are attributable to past occupational exposure — far exceeding the toll from traumatic workplace fatalities. The long latency period of occupational cancers (typically 20–40 years between exposure and disease) means that current work practices today will determine cancer rates in the 2040s and 2050s.

The most significant occupational carcinogens in terms of Australian disease burden include:

• Solar ultraviolet radiation (outdoor workers — the largest single contributor)
• Crystalline silica dust (stonemasons, miners, tunnel workers)
• Asbestos (construction, maintenance, plumbers, electricians)
• Diesel engine exhaust (transport, mining, construction)
• Benzene (petroleum refining, laboratory work)
• Wood dust (timber industry, furniture manufacturing)
• Formaldehyde (healthcare, pathology, embalming)
• Hexavalent chromium (chrome plating, stainless steel welding)
• Polycyclic aromatic hydrocarbons / PAHs (bitumen work, coke ovens)

How WES Values Differ for Carcinogens

For most non-carcinogenic chemicals, the WES is set at a level where the vast majority of workers can be exposed repeatedly throughout a working lifetime without adverse health effects. The WES represents a threshold below which harm is unlikely.

For carcinogens, the situation is fundamentally different. Genotoxic carcinogens (those that damage DNA) are assumed to have no safe threshold — any exposure carries some finite risk. The WES for a carcinogen is therefore not a “safe level” but rather a level that represents an acceptable (but not zero) risk given practical and economic constraints.

Safe Work Australia flags substances in the WES document with specific notations:

• (C) — Confirmed carcinogen: Sufficient evidence in humans that exposure causes cancer (IARC Group 1)
• (PC) — Probable carcinogen: Strong evidence but not yet confirmed in humans (IARC Group 2A)
• (SC) — Suspect carcinogen: Limited evidence (IARC Group 2B or equivalent)

The presence of these notations imposes a higher duty on employers: not merely to comply with the WES but to minimise exposure to as low as reasonably practicable (ALARP) using the hierarchy of controls.

The ALARP Principle for Carcinogens

ALARP — as low as reasonably practicable — is the core risk management principle of Australian WHS law. It means that after identifying a hazard and assessing the risk, you must reduce the risk to the lowest level practicable, weighing the cost and difficulty of further risk reduction against the benefit achieved.

For carcinogens, ALARP means:

• Compliance with the WES is necessary but not sufficient. If further reductions are reasonably practicable, they are legally required.
• The hierarchy of controls must be applied in order: Elimination and substitution first; engineering controls second; administrative controls third; PPE last.
• The “reasonably practicable” test includes financial considerations, but cost is not a defence where the risk is high and the cost of control is proportionate. For a substance that causes cancer at any dose, the bar for ALARP compliance is high.
• Documentation of ALARP decision-making is important for due diligence. Demonstrating that you considered all control options and implemented those that are reasonably practicable protects officers from personal liability.

Substitution: The Most Effective Carcinogen Control

Substitution of a carcinogen with a safer alternative is the most effective control measure. Examples of substitution in practice:

• Water-based coatings replacing benzene-containing solvent blends
• Low-Cr(VI) welding consumables for stainless steel, reducing fume Cr(VI) generation
• Phenol-formaldehyde resin replacement with formaldehyde-free alternatives in some bonding applications
• Water misting and wet drilling methods replacing dry silica-generating operations
• Synthetic amorphous silica alternatives to crystalline silica fillers in some applications

Substitution is often commercially feasible but requires an active procurement and chemical management program — carcinogenic substances are frequently specified by habit or historical practice rather than necessity.

Health Surveillance for Carcinogen Exposure

For confirmed carcinogens, health surveillance programs should include:

• Baseline health assessment before commencing exposure (allows detection of pre-existing conditions that may increase risk)
• Periodic surveillance during the exposure period (frequency depends on the carcinogen and exposure level)
• Post-employment surveillance for the latency period of the relevant cancer (can be 20–40 years — a significant commitment)
• Record keeping for the post-employment surveillance period (minimum 30 years for many carcinogens under WHS Regulations)

Health surveillance does not prevent cancer, but it can detect it earlier when treatment is more effective. It also creates a documented record of exposure that supports workers’ compensation claims for occupational cancer.

Officer Duties and Personal Liability for Carcinogen Management

Under the WHS Act, officers (directors, senior executives) have a personal duty of due diligence in relation to the PCBU’s WHS obligations. A failure to implement ALARP controls for carcinogens — particularly where the carcinogen has been identified and the controls are well-established — can expose officers to personal prosecution and significant penalties.

The due diligence duty requires officers to “acquire and keep up-to-date knowledge” of WHS matters and to “understand the operations of the PCBU and the hazards and risks associated with those operations.” Ignorance of the carcinogen status of substances used in the business is not a defence.

Frequently Asked Questions

If we comply with the WES for a carcinogen, are we legally protected?

No. WES compliance is a minimum standard, not a guarantee of legal protection. Australian WHS law requires ALARP risk management, which goes beyond WES compliance. If further controls are reasonably practicable but not implemented, a PCBU can be found liable even if WES values are not exceeded. NATA-accredited occupational hygienists, such as those at Anitech, can document ALARP decision-making as part of a due diligence program.

How do I know if a substance I use is classified as a carcinogen?

Check the SDS (Section 2 for GHS hazard classification and Section 11 for toxicological information). The Safe Work Australia WES document includes carcinogen notations for all listed substances. IARC Monographs (freely available online) provide the most comprehensive international carcinogen classification database. Substances without a WES but used in your workplace should be assessed against IARC, EU CLP, or other authoritative sources.