Manganese (dust \/ fume \/ compounds, as Mn) is a **WES_reduced** listing. Previous WES expressions in the CSV extract sit at **TWA 1 (dust); 1\/3 (fume)** mg\/m\u00b3. From **1 December 2026**, the Workplace Exposure Limit is **Inhalable 0.1; respirable 0.02** mg\/m\u00b3 **as Mn** (per Safe Work Australia\u2019s published changes and our CSV extract). That is a **dual-fraction** WEL \u2014 one metal, two method decisions.<\/p>\n
Until **30 November 2026**, the current WES list still governs airborne contaminant compliance. From **1 December 2026**, WEL applies once given effect in your jurisdiction. **Check your WHS regulator** for adoption and any local commencement detail \u2014 national policy documents are not a substitute for jurisdictional law.<\/p>\n
## Why this matters for PCBUs<\/p>\n
Mining, mineral processing, welding and foundry sites often still talk about \u201cmanganese fume at 1\u201d or \u201cdust at 1\u201d as if a single sampler answers the December question. It does not. You must know whether you are defending **inhalable 0.1** or **respirable 0.02** (as Mn) \u2014 and your lab report must say which fraction was collected.<\/p>\n
If the register still quotes the old dust\/fume pair without fraction language, fix the register before you argue about results.<\/p>\n
## Where manganese shows up<\/p>\n
Typical Australian settings:<\/p>\n
– Mining and mineral processing \u2014 ore handling, milling, concentrate transfer
\n– Welding and fabrication \u2014 Mn-bearing consumables, stainless and high-Mn wires, confined repair
\n– Foundries \u2014 melting, pouring, shake-out, grinding of Mn steels
\n– Smelting and refining support tasks
\n– Battery materials and specialty alloy powder handling (where Mn compounds are present)
\n– Maintenance on dust collectors, baghouses and ventilation serving Mn processes
\n– Contract grinders and mobile welders who inherit plant dust histories<\/p>\n
Fume-dominant welding SEGs and dust-dominant milling SEGs are not interchangeable \u2014 even when both are \u201cmanganese as Mn\u201d on the WEL list.<\/p>\n
## SEG walkthrough (fabrication + foundry colour)<\/p>\n
Imagine a site with a weld bay using Mn-bearing wire and a small foundry grind booth finishing Mn steel castings.<\/p>\n
**SEG candidates**<\/p>\n
1. **Welders \u2014 production bay** \u2014 continuous MIG\/FCAW on Mn consumables
\n2. **Welders \u2014 confined repair** \u2014 short duration, poor dilution, different profile
\n3. **Grinders \/ finishers** \u2014 respirable-rich aerosol from powered tools
\n4. **Furnace \/ pour crew** \u2014 fume and dust mix at melt and pour
\n5. **Baghouse \/ maintenance** \u2014 filter change and duct cleaning
\n6. **Mobile contractors** \u2014 inherit both weld and grind exposures without appearing on the roster map<\/p>\n
**Walkthrough questions with ops**<\/p>\n
– Which consumables actually contain Mn \u2014 and are they named on the register?
\n– Do you sample **inhalable**, **respirable**, or both \u2014 and why?
\n– Who grinds after welding \u2014 same SEG or a new aerosol profile?
\n– Are night maintenance crews who open collectors in the SEG map?
\n– Does anyone still cite **TWA 1** as if it remains the WEL comparator?<\/p>\n
Build SEGs from tasks and aerosol generation, not from \u201cmetal trades\u201d as a single bucket.<\/p>\n
## Register and SEG questions for HSE \/ ops<\/p>\n
1. **Are manganese dust, fume and compounds named as Mn** on the hazardous chemical \/ airborne contaminants register?
\n2. **Which SEGs** could inhale Mn \u2014 weld, grind, mill, pour, baghouse, contractors?
\n3. **Does paperwork still cite WES dust 1 \/ fume 1\/3** without the incoming dual WEL?
\n4. **Have you recorded fraction decisions** \u2014 inhalable **0.1** vs respirable **0.02** \u2014 per SEG objective?
\n5. **Is there historical monitoring** that states fraction and \u201cas Mn\u201d reporting basis?
\n6. **Who owns eliminate \/ substitute \/ LEV** before RPE becomes the default on grind and weld?
\n7. **Are SDS and emergency procedures** current for Mn-bearing consumables and powders?
\n8. **Do contractors** appear in the SEG map with Mn named?<\/p>\n
If welding procedures specify Mn wire but the register is silent, fix the register first.<\/p>\n
## Controls that actually move the dial<\/p>\n
### Eliminate \/ substitute
\n– Can consumables move to lower-Mn alternatives where process allows?
\n– Can grind move to wet methods or enclosed booths?
\n– Can powder handling move to closed transfer?
\nDocument residual risk \u2014 substitution is a decision record.<\/p>\n
### Engineering
\n– On-torch extraction and booth LEV for weld; verified capture on grind booths
\n– Enclosed transfer and maintained filtration on mineral-processing dust paths
\n– Treat baghouse pulse and duct cleaning as engineered events with written isolation
\n– Design filter change for settle \/ break sequences that cut open volume<\/p>\n
### Administrative
\n– Separate weld, grind and mill SEGs in training and monitoring plans
\n– Written methods for confined weld repair; restrict non-essential people
\n– Consumable control \u2014 issue Mn wire deliberately, not from an unmarked rack
\n– Stop-work triggers for LEV failure or visible fume escape \u2014 without treating smell as a calibrated instrument<\/p>\n
### PPE
\n– RPE selected for fume \/ dust and expected concentration, with fit testing and change rules
\n– Eye \/ face \/ skin protection aligned with grind and weld tasks
\n– PPE last \u2014 never the only control on a grind booth that can be enclosed<\/p>\n
## Monitoring and readiness without jumping the gun<\/p>\n
– Confirm presence and SEGs, including contractors and maintenance
\n– Get baseline data against **inhalable 0.1** and\/or **respirable 0.02** mg\/m\u00b3 as Mn \u2014 matching the fraction to the SEG objective
\n– Include weld, grind and baghouse tasks \u2014 full-shift only on a light fabrication day understates risk
\n– Close obvious engineering and admin gaps now
\n– Align training with **manganese as Mn** and the dual WEL numbers
\n– Ask your OH provider to state fraction, sampler type and \u201cas Mn\u201d basis on every report<\/p>\n
Do **not** invent additional mg\/m\u00b3 figures beyond the published WEL pair. Do **not** treat old dust **1** \/ fume **1\/3** as the December WEL comparators. Do **not** claim early jurisdictional adoption without regulator confirmation. Method colour (which Australian \/ ISO sampler conventions apply) should be confirmed with your hygienist and lab before you lock a programme \u2014 cite method IDs in reports, not in marketing copy.<\/p>\n
## Common mistakes<\/p>\n
– One \u201cMn sample\u201d filed against both WEL fractions
\n– Still quoting WES **1** \/ **1\/3** in Dec readiness packs
\n– Welding SEG only \u2014 skipping grind and baghouse
\n– RPE without fit testing on multi-hour grind days
\n– Contractors invisible on the SEG map
\n– Mixing cobalt \/ cadmium \/ beryllium messaging into the same primary without separate listings<\/p>\n
## FAQ \u2014 HSE and operations<\/p>\n
### Which number do we manage to \u2014 0.1 or 0.02?
\nBoth are published WEL expressions for manganese as Mn: **inhalable 0.1** and **respirable 0.02** mg\/m\u00b3. Your SEG objective and sampler fraction decide which comparison is valid for a given result.<\/p>\n
### Is the old fume 1\/3 still the WEL?
\nNo. Plan to the published WEL pair: **Inhalable 0.1; respirable 0.02** mg\/m\u00b3 as Mn.<\/p>\n
### Do we need two samplers on every person?
\nNot always \u2014 but you need a written fraction decision per SEG. Some programmes run both fractions on priority SEGs until controls are understood.<\/p>\n
### When does WEL \u201ccount\u201d?
\nWES until **30 November 2026**; WEL from **1 December 2026** once implemented \u2014 **verify with your WHS regulator**.<\/p>\n
## Sources<\/p>\n
– Safe Work Australia, *Changes to Workplace Exposure Limits \u2013 May 2025* (PDF): https:\/\/www.safeworkaustralia.gov.au\/sites\/default\/files\/2025-05\/changes_to_workplace_exposure_limits_-_may_2025.pdf
\n– SWA WEL \/ WES changes page: https:\/\/www.safeworkaustralia.gov.au\/safety-topic\/managing-health-and-safety\/workplace-exposure-limits-airborne-contaminants\/changes-between-wes-and-wel
\n– `\/workspace\/wel\/wes-to-wel-changes-2026.csv` \u2014 Manganese WES_reduced; WEL Inhalable 0.1; respirable 0.02 as Mn
\n– Nov-pack FINAL ideas: `\/workspace\/anitech-social\/nov-pack-research-2026-09-16\/FINAL-25-30-IDEAS.md` (idea 3)<\/p>\n
## Next step<\/p>\n
If manganese dust, fume or compounds are present in weld, grind, mill or foundry tasks on your site, book a consult to lock fraction decisions, SEGs and a monitoring plan before the WEL date.<\/p>\n
**Book a consult:** [anitechgroup.com](https:\/\/anitechgroup.com) \u00b7 **sales@anitechgroup.com**<\/p>\n","protected":false},"excerpt":{"rendered":"
Manganese (dust \/ fume \/ compounds, as Mn) is a **WES_reduced** listing. Previous WES expressions in the CSV extract sit at **TWA 1 (dust); 1\/3 (fume)** mg\/m\u00b3. From **1 December 2026**, the Workplace Exposure Limit is **Inhalable 0.1; respirable 0.02** mg\/m\u00b3 **as Mn** (per Safe Work Australia\u2019s published changes and our CSV extract). That is…<\/p>\n","protected":false},"author":1,"featured_media":13648,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"content-type":"","inline_featured_image":false,"footnotes":""},"categories":[1],"tags":[],"ppma_author":[253],"class_list":["post-13652","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog"],"yoast_head":"\n