Managing Contractor WHS: Occupational Hygiene Obligations When Using Contractors

Many Australian businesses engage contractors to perform specialist, maintenance, construction or service tasks — often tasks that generate the highest occupational hygiene hazards. Assuming that the contractor is solely responsible for the health of their workers when they enter your site is a legally dangerous misconception. The model Work Health and Safety Act 2011 explicitly creates shared, concurrent duties when multiple PCBUs work together — and the failure of one PCBU to discharge its obligations does not excuse another.

The Concurrent Duty Principle

Section 16 of the model WHS Act states that where more than one person has a duty in relation to the same matter, each person retains that duty. A contractor performing silica-generating cutting work on a host site has duties to manage their workers’ RCS exposure — and so does the host site PCBU, to the extent that they manage or control the work. If the contractor fails to provide wet cutting controls and workers develop silicosis, both the contractor PCBU and the host PCBU may be held liable for failing their respective duties.

What “Extent of Management or Control” Means

The host PCBU’s duty is proportional to their actual control over the work. Where the host:

• Specifies the work method (how cutting is to be done) — they have significant control and responsibility for hygiene hazards associated with that method
• Provides the work area and physical environment — they are responsible for environmental factors (general ventilation, housekeeping, shared plant)
• Provides plant or equipment — they are responsible for its safe condition
• Supervises the work — they have responsibility for the work as performed

Conversely, where the contractor is a specialist engaged for their expertise and controls their own work method, the host’s duty is more limited — but still includes ensuring the contractor has been informed about site-specific hazards and ensuring the contractor’s approach is at least plausibly adequate.

Pre-Qualification for Occupational Hygiene Capability

Contractor pre-qualification is the primary tool for managing hygiene risks from contractors. Before engaging contractors for hazardous work, the host PCBU should assess:

• Does the contractor have documented WHS procedures for the hazardous work involved (e.g., silica control procedure for concrete cutting)?
• For air monitoring obligations — does the contractor use a NATA-accredited laboratory? Can they provide recent monitoring results for similar work?
• For health surveillance triggers — does the contractor have an active health monitoring programme for relevant workers? Can they evidence enrolment and current results?
• Are workers adequately trained, with fit-test records for required respirators?
• Does the contractor have appropriate engineering controls (wet cutting equipment, on-tool extraction)?

Pre-qualification should not be a tick-and-flick exercise — asking for evidence and verifying it (requesting copies of recent monitoring reports, checking NATA laboratory accreditation) is appropriate diligence. Where a contractor cannot evidence adequate hygiene capability, either the scope must be modified to ensure the host provides the controls, or a more capable contractor engaged.

Hazard Information Sharing

Section 46 of the model WHS Act creates a duty to consult with other PCBUs sharing the workplace about hazards and risks. For occupational hygiene, this means:

• Informing contractors about site-specific hazards they may encounter — asbestos-containing materials in a building being worked on, previous chemical contamination in soil, existing noise levels
• Providing the chemical register and relevant SDS for chemicals the contractor may encounter on site (not just chemicals they bring)
• Informing the contractor of monitoring results and health surveillance requirements for specific hazards on site

Contractor induction is the standard mechanism for hazard information transfer — but the induction must actually cover the specific hygiene hazards of the work, not just generic site rules.

Monitoring Contractor Hygiene Compliance

The host PCBU should have mechanisms to verify that contractor hygiene commitments are being honoured during work:

• Site walk-throughs to observe control use (are wet cutting tools actually being used with water flowing? is RPE worn?)
• Stop-work authority for non-compliant contractor work — documented in the site safety management plan
• Requiring contractor submission of monitoring results upon completion of monitoring-required work
• Incident reporting coordination — contractor incidents involving hygiene hazards (overexposure incidents, health surveillance positives) should trigger review of the work method on the host site