Flour Handling SWMS

Bulk flour handling operations upstream of bakery production lines expose workers to inhalable flour dust, a recognised respiratory sensitiser and a Class St1 combustible dust capable of deflagration in confined volumes. Activities covered include tanker discharge to silos, silo blow-off and venting, mechanical and pneumatic transfer, weighing, and manual bag tipping into hoppers. Under WHS Regulation 2025 Part 7.1, flour is a hazardous chemical requiring a documented risk assessment, exposure monitoring against the new 0.5 mg/m³ inhalable workplace exposure limit effective 1 December 2026, and atmospheric control. Silo internal cleaning and inspection additionally engage Part 4.3 confined space duties. A Safe Work Method Statement is mandatory because the work is High Risk Construction Work-equivalent food-sector hazardous chemical work triggering section 291 category, and because baker's asthma is a notifiable occupational disease under Part 3 incident notification provisions.

Hazards identified

7 hazards covered, sorted by priority.

Control measures

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

1. 1Elimination — Replace manual bag tipping with sealed bulk silo delivery and enclosed pneumatic transfer to eliminate operator exposure to airborne flour dust at the source.
2. 2Elimination — Prohibit silo internal entry by specifying external silo cleaning systems, rotary bin dischargers and air cannons that clear bridging without confined space entry.
3. 3Substitution — Where additive dusts are required, substitute fine powders with agglomerated, low-dusting or liquid-slurry equivalents reducing inhalable fraction generated during charging.
4. 4Engineering — Install LEV capture hoods over bag-tip stations achieving 1.0 m/s face velocity, ducted to ATEX-rated cartridge filters with explosion venting per AS/NZS 60079.10.2.
5. 5Engineering — Fit silo pressure/vacuum relief valves rated 0.35 bar, rotary airlock isolation, earthing/bonding straps and explosion isolation valves on inlet ducts per HB 239.
6. 6Engineering — Provide continuous inhalable dust monitoring with real-time photometric sensors alarmed at 0.4 mg/m³ to give pre-WEL warning under WHS Reg 2025 cl 50.
7. 7Administrative — Implement permit-to-work for silo entry covering atmospheric testing, isolation of fill lines, top-man standby and tripod rescue, reviewed each shift by the supervisor.
8. 8Administrative — Schedule annual health surveillance including spirometry and specific IgE testing for all flour-exposed workers, with results reviewed by an occupational physician.
9. 9Administrative — Conduct documented pre-start briefings using this SWMS, restrict tanker discharge to trained operators and verify silo ullage before connection.
10. 10PPE — Issue P2 respirators (fit-tested annually to AS/NZS 1715), antistatic conductive footwear, sealed eye protection and disposable Type 5 coveralls during bag tipping and cleaning tasks.

Applicable Codes of Practice

Worked example

At a mid-sized commercial bakery preparing for a 6 am tanker discharge to Silo 3, the shift supervisor opens this SWMS at the pre-start brief with the receiving operator and the tanker driver. Working through the hazard register, the operator identifies that the silo high-level alarm was intermittent the previous shift, so the team flags pneumatic over-pressurisation as the live risk and selects the engineering control requiring confirmed ullage measurement and pressure-relief valve verification before coupling. The driver signs onto the SWMS, confirms his earthing strap and antistatic footwear, and the supervisor witnesses the bonding connection to the silo earth point. During discharge, the real-time dust monitor near the filter vent alarms at 0.42 mg/m³, below the WEL but above the pre-alarm threshold built into the administrative control. Following the SWMS escalation step, the operator throttles the blower, dons a fit-tested P2 respirator and isolates the adjacent bag-tip station until readings drop. Post-discharge, the supervisor records the alarm event in the exposure log, schedules a filter inspection, and updates the SWMS dynamic risk section so the next shift inherits the control change. The document is re-signed by all attending workers and filed against the batch record for the two-year retention period.

Related legislation

• WHS Act 2011 (model)
• WHS Regulation 2025
• Combustible Dust CoP; AS/NZS 4024 — Safety of machinery

Frequently asked questions