Respirable barium sulfate is a new WEL listing at 1.35 mg/m³ (8-hour TWA). Inhalable barium sulfate is separate; do not collapse fractions. WES applies until 30 November 2026, then WEL applies once implemented. Check your WHS regulator.
Why PCBUs should act now
Powder handling, bag cutting, hopper charging, milling, screening, fillers, plastics compounding, pack-out, damaged bags and dust-collector work can generate respirable aerosol. “Dust controlled by P2” is not a fraction-specific assessment.
SEG walkthrough
- Name tasks: bag tip/weigh, disperser charge, clean-down and filter service.
- Identify where respirable aerosol is generated and group workers by profile, not job title.
- Sample campaign days, including tip, clean-down and contractor filter changes.
- Record sampler fraction, enclosure, LEV, cleaning method and shift pattern.
Register and controls
Check the chemical register, SDS, fraction, contractors and LEV ownership. Prefer slurry or closed transfer where practicable. Engineer enclosed transfer, local exhaust and collector integrity. Use HEPA vacuuming, clean-down SOPs and filter-change permits; PPE is last.
Monitoring readiness
Commission personal samples using the respirable fraction, documented sampler and flow. Compare results to 1.35 mg/m³, state LOD/LOQ, blanks and partial-shift weighting, and use enough replicates to show variability. Static samples diagnose LEV only. Visible dust is a clue, not a clearance.
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