Biological Hazards on Construction Sites | WHS Guide

Biological hazards are substances or agents of biological origin that can harm people. They include viruses, bacteria, parasites, some fungi such as mould, and biological allergens, irritants and toxins such as organic dust, sap and venom.

For builders and tradies, the practical answer is to identify possible sources before disturbing them, work out how exposure could occur, and put effective controls in place before the task starts.

Biological hazards are not limited to hospitals or laboratories. On construction, maintenance, demolition and civil sites, they may be found in:

sewage, wastewater, stagnant water and flood-affected materials
mouldy plasterboard, insulation, timber and furnishings
soil, compost, mulch, manure and organic dust
bird or animal droppings, carcasses, pests and nesting areas
discarded needles and other contaminated sharps
blood, vomit or other body substances
cooling towers, water systems and poorly maintained ventilation
mosquitoes, ticks, fleas and other disease-carrying vectors
infectious people in shared vehicles, amenities or enclosed work areas.

Workers may be exposed by breathing contaminated air or dust, swallowing contaminated material, contact with the eyes, nose, mouth or skin, or through cuts, punctures, bites and damaged skin. Many biological hazards are not visible, so a clean-looking area is not always a safe area.

What should be sorted before work starts?

Start with the actual task and location. Review site history, previous flooding or water damage, pest activity, known contamination, existing reports and information from the principal contractor, client or building manager.

Walk through the work area and consult the people who will do the job. Subcontractors often know where dust will be generated, what must be opened or disturbed and where ordinary controls will be difficult to use.

Before starting, confirm:

the likely source of contamination and possible exposure routes
whether testing or specialist advice is needed
who could be exposed, including other trades, occupants and visitors
whether the source can be removed or the work avoided
how the area will be isolated and access controlled
suitable equipment, ventilation, dust suppression or containment
hygiene, washing, decontamination and waste arrangements
required PPE and respiratory protection, including fit testing where relevant
what workers must do after a suspected exposure.

Managing biological hazards follows the usual risk process: identify hazards, assess the risks, control them, then maintain and review the controls. Biological risks can change quickly, particularly after flooding, weather events, pest activity, disease outbreaks or changes to the work area.

What good controls and documents usually cover

Effective control normally uses a combination of measures. Eliminate the exposure where reasonably practicable. If that cannot be done, consider substitution, isolation and engineering controls before relying on procedures and PPE.

Depending on the work, practical controls may include removing contaminated material under controlled conditions, restricting access, using barriers or sealed enclosures, providing suitable ventilation or extraction, suppressing contaminated dust, arranging safe sharps handling, cleaning and disinfecting equipment, and securely containing waste.

Site documentation commonly includes:

a biological hazard or task risk assessment
the site hazard register and pre-start information
a safe work procedure for cleaning, removal or decontamination
inspection, ventilation, water-system or maintenance records
PPE and respiratory-protection requirements
worker consultation, instruction and training records
an exposure, first aid, incident and emergency response procedure
waste containment and disposal arrangements.

Procedures should set clear responsibilities and explain how the task is performed safely. Workers need suitable information, training, instruction and supervision covering the hazard, controls, PPE, reporting process and exposure response. Controls should be checked in the field and reviewed when circumstances change or an exposure, illness, complaint or control failure occurs.

When does a SWMS apply?

A biological hazard does not, by itself, mean every task needs a safe work method statement. A SWMS commonly applies when the work is legally classified as high-risk construction work. Where biological exposure is part of that work, the SWMS should identify the relevant hazard and set out the controls, implementation and review arrangements.

For other work, a site-specific risk assessment, safe work procedure, permit, contamination plan or exposure-response procedure may be more suitable. The document should match the work rather than being a generic form copied from another project.

Local requirements vary between Australian jurisdictions. Check current regulator material and the rules applying to the project before deciding what documentation is required.

Warning signs that need action

Pause and reassess the work if you find unexpected mould, sewage, sharps, droppings, carcasses, contaminated water, heavy organic dust or pest activity. Other warning signs include strong musty odours, visible water damage, failed ventilation, overflowing waste, unavailable washing facilities or workers using PPE that does not fit.

Reports of unusual breathing irritation, skin reactions, bites, punctures, gastrointestinal illness or suspected infectious exposure should trigger the site response process. Record what happened, protect others from the area and obtain appropriate first aid, medical or specialist support.

How Blue Safe can help

Blue Safe provides compliant WHS documents tailored to the client's activities, applicable Australian WHS/OHS requirements, jurisdiction and industry. This can include risk assessments, SWMS, safe work procedures, biological hazard controls, consultation records, training tools and exposure-response processes suited to the work being performed.

Blue Safe guarantees the document compliance of the WHS documents it provides, including eligible customer documents after Blue Safe has reviewed and upgraded them.

Customers actively put the compliant documents into practice through controls, consultation, training, actions, records and evidence. This gives supervisors and workers a clear, practical system for planning the work, applying controls and demonstrating what occurred on site.

Official sources

The national Model Code provides general orientation and is not automatically the applicable law in every jurisdiction. Information current: 6 August 2026.

Biological Hazards at Work: A Practical Construction Guide