Dry Ice / CO2 Blasting SWMS

Dry ice (CO2) blasting uses solid carbon dioxide pellets accelerated through a compressed air stream at velocities up to 300 m/s to clean industrial surfaces, mould tools, electrical switchgear, food processing equipment and heritage substrates without secondary waste. The process introduces three simultaneous WHS hazards rarely encountered together on conventional cleaning jobs: cryogenic temperatures of -78.5°C at the nozzle, rapid sublimation that displaces breathable oxygen in confined or poorly ventilated spaces, and high-pressure pneumatic kinetic energy. Under WHS Regulation 2011 r291 and the harmonised 2025 amendments, this work meets the definition of High Risk Construction Work where conducted on construction sites, and the PCBU must prepare a Safe Work Method Statement before work commences. Even outside construction settings, r34-38 require documented risk assessment for confined space entry and hazardous chemical exposure. This SWMS provides the structured hazard identification, hierarchy-of-control measures and sign-on framework operators, supervisors and principal contractors need to demonstrate due diligence and worker consultation under s47 of the WHS Act.

Hazards identified

7 hazards covered, sorted by priority.

Control measures

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

1. 1Elimination — Eliminate confined space blasting where alternative dismantling allows component removal to open, mechanically ventilated workshop areas before CO2 cleaning commences.
2. 2Elimination — Remove all non-essential personnel from the 5-metre exclusion zone and isolate adjacent workspaces with physical barriers and signage during blasting operations.
3. 3Substitution — Substitute high-pressure (16 bar) blast settings with low-pressure soft-blast pellets for delicate substrates, reducing noise, ricochet velocity and CO2 consumption.
4. 4Engineering — Install mechanical extraction ventilation delivering minimum 6 air changes per hour and continuous O2 monitoring with audible alarms set at 19.5% per AS 2865.
5. 5Engineering — Use anti-static conductive blast hose rated to manufacturer specification and bond/earth the blast machine to substrate per AS/NZS 1020 static control requirements.
6. 6Engineering — Fit acoustic enclosures or blast cabinets where geometry allows, supplemented by sound-attenuating nozzle silencers reducing noise at source per AS/NZS 1269.1.
7. 7Administrative — Issue Confined Space Entry Permit, conduct atmospheric testing before entry and maintain continuous standby attendant with rescue equipment per AS 2865:2009.
8. 8Administrative — Limit operator blast duration to maximum 2-hour rotations with mandatory warm-up breaks and document training competency under AS/NZS 4801 framework.
9. 9PPE — Issue cryogenic-rated leather gauntlet gloves (EN 511), face shield over Class 1 safety glasses, Class 5 hearing protection and abrasion-resistant blast suit.
10. 10PPE — Supply airline-fed respiratory protection or SCBA per AS/NZS 1715/1716 when O2 cannot be assured above 19.5% throughout the entire work cycle.

Applicable Codes of Practice

High-Risk Construction Work triggered

Worked example

On a brewery fermentation tank cleaning contract, the supervisor opens this SWMS at the 6:30am pre-start brief in the site shed. The crew of three — one blast operator, one hose tender, one confined space standby — walks through each hazard row on the printed document. When they reach 'Oxygen depletion from CO2 sublimation', the supervisor cross-references the Confined Space Entry Permit and confirms the 600mm extraction ducting is positioned at the tank base where CO2 (heavier than air) will pool. Atmospheric testing logs 20.9% O2 baseline. The operator signs the PPE row confirming receipt of cryogenic gauntlets, airline-fed half-face respirator, Class 5 earmuffs and blast suit. Mid-task at 9:15am the standby attendant's continuous O2 monitor alarms at 19.8% — referencing the SWMS administrative control, the crew immediately ceases blasting, evacuates the tank, increases extraction fan speed and waits 12 minutes until O2 recovers to 20.6% before re-entry. The supervisor annotates the SWMS field-adjustment column noting the extraction increase and re-briefs the crew. At end of shift the signed SWMS, permit and atmospheric log are filed to the principal contractor's records system per the 2-year retention requirement.

Related legislation

• WHS Act 2011 (model)
• WHS Regulation 2025
• Managing Risks of Hazardous Chemicals CoP; Construction Work CoP

Frequently asked questions