Mulching & Soil Amendment SWMS

Mulching and soil amendment works involve the bulk delivery, handling and placement of organic mulches, composts and soil conditioners across landscape beds on commercial, civil and residential development sites. The work commonly combines tipper or blower-truck off-loading, repetitive wheelbarrow transfer, raking and spreading, weed-mat installation, and edge restraint fitting — often adjacent to live traffic, public access zones or active construction. Under the WHS Regulation 2025, the activity is captured as construction work and crosses several High Risk Construction Work under section 291 triggers including sustained hazardous manual tasks, exposure to airborne respirable organic dust and bioaerosols, and interaction with mechanically powered mulching and blowing plant. A documented Safe Work Method Statement is therefore mandatory before work commences and must be available at the workplace for inspection, signed onto by every worker, and reviewed if the method, plant or site conditions change.

Hazards identified

7 hazards covered, sorted by priority.

Control measures

Hierarchy-of-controls order: elimination → substitution → isolation → engineering → administrative → PPE.

1. 1Elimination — Specify direct blower-truck placement into beds via hose to eliminate manual barrow runs and shovel transfer wherever vehicle access and overhead clearance permit.
2. 2Elimination — Reject delivery loads showing visible steam, internal temperature above 70°C or sour odour; require supplier to restockpile and cool before site acceptance.
3. 3Substitution — Specify pre-wetted, screened, composted mulch (AS 4454 compliant) rather than dry uncomposted woodchip to reduce dust generation and bioaerosol release at point of application.
4. 4Substitution — Replace powdered lime with pelletised or prilled soil amendments to reduce airborne alkaline dust during broadcast spreading.
5. 5Engineering — Fit blower-truck hoses with operator-end emergency stop lanyards, guard all augers and fans to AS 4024.1 and lock out plant before any blockage clearing.
6. 6Engineering — Establish exclusion zones with temporary fencing and physical spotter barriers around reversing tippers and bobcats, separating pedestrian routes from plant movement paths.
7. 7Administrative — Rotate workers through shovelling, barrowing and raking tasks on a maximum 45-minute cycle and schedule mulching during cooler parts of the day to limit heat and fatigue load.
8. 8Administrative — Conduct a documented pre-start sharps and contamination sweep of each bed, with a written exclusion procedure for syringes and biohazards routed to a licensed waste contractor.
9. 9PPE — Issue P2 respirators (AS/NZS 1716) for all dry-mulch handling, sealed safety eyewear (AS/NZS 1337.1), chemical-resistant nitrile gloves, long sleeves and steel-cap boots.
10. 10PPE — Provide hi-vis day/night garments to AS/NZS 4602.1 plus puncture-resistant gloves rated to EN 388 4.4.4.x when handling unscreened mulch or working near suspected sharps.

Applicable Codes of Practice

High-Risk Construction Work triggered

Worked example

On a mid-rise residential development handover, a landscape leading hand is mobilising a three-person crew to place 40 cubic metres of composted hardwood mulch across podium-level garden beds, with a blower truck booked for the morning. At the pre-start brief, the leading hand opens this SWMS on a site tablet and walks the crew through the hazard register — focusing on the blower-truck auger entanglement risk, respirable dust, and the reversing truck path adjacent to a public footpath. The crew confirm that pre-wetted AS 4454 compliant mulch has been delivered, infrared-checking the stockpile reads 48°C (within accepted range), and the substitution control therefore holds. Each worker is fit-tested for their P2 respirator and signs onto the SWMS on the tablet. Mid-task, the blower hose blocks; rather than reaching into the chute, the hose operator activates the lanyard E-stop in line with the engineering control, the driver isolates and tags the auger, and the blockage is cleared with a non-conductive rod. The leading hand records the deviation, adds a toolbox note that future loads should be screened finer, and the amended SWMS is re-signed before work resumes after lunch.

Related legislation

• WHS Act 2011 (model)
• WHS Regulation 2025
• AS 4373 — Pruning of amenity trees; Managing Risks of Hazardous Chemicals CoP

Frequently asked questions