Rung one, at any quantity: label, SDS, register
A hazardous chemical under the WHS Regulations is any substance, mixture or article that meets one or more hazard classes of the Globally Harmonised System of Classification and Labelling of Chemicals (GHS), as modified by Schedule 6. Since 1 January 2023, classification and labelling must use the GHS's 7th revised edition, after a two-year transition through 2021 and 2022. Classification is the manufacturer's or importer's job, and it drives everything downstream: the signal word, hazard statements and pictograms on the label, and the content of the safety data sheet.
The PCBU's rung-one duties attach the moment any quantity of a hazardous chemical is used, handled or stored. Containers and pipework must be correctly labelled. The current SDS must be obtained from the manufacturer, importer or supplier no later than first supply and before the chemical is used, and the code is blunt that a third-party SDS is not by itself enough: the Australian manufacturer's or importer's SDS must be obtained. Regulation 344 then requires the SDS to be readily accessible to workers who use, handle or store the chemical, and to emergency service workers. Regulation 346 requires a register, which is simply the list of product names of every hazardous chemical at the workplace with the current SDS for each attached, kept up to date as chemicals arrive and are discontinued. Regulation 328 carves out the obvious cases: retail consumer stock, packaged food and drink, tobacco, therapeutic goods at the point of use, and chemicals in transit under transport law.
Rungs two and three: the Schedule 11 thresholds
Selected placard and manifest quantities from Schedule 11 of the model WHS Regulations, as reproduced in Appendix D of the hazardous chemicals code (Table 10). The full table runs to dozens of hazard classes; these are the rows most small and medium operations meet first.
| Hazard class and category | Placard quantity | Manifest quantity |
|---|---|---|
| Flammable liquids, category 1 (e.g. some solvents) | 50 L | 500 L |
| Flammable liquids, category 2 (e.g. petrol-class) | 250 L | 2,500 L |
| Flammable liquids, category 3 | 1,000 L | 10,000 L |
| Flammable liquids, category 4 (e.g. diesel-class) | 10,000 L | 100,000 L |
| Flammable gases, category 1A/1B | 200 L | 5,000 L |
| Aerosols, categories 1 to 3 | 5,000 L | 10,000 L |
| Oxidising liquids and solids, category 1 | 50 kg or L | 500 kg or L |
Cross the placard quantity for any class and placards go up: durable signs at the storage location and outer warning placards where relevant. One detail catches people out: where Schedule 13 requires a placard, it must carry the dangerous goods class label, the transport diamond, not the corresponding GHS pictogram from the container label.
Cross the manifest quantity, ten to twenty-five times higher, and regulation 347 requires a manifest: a written summary of the classification, quantity and location of the Schedule 11 chemicals on site, with site plans and emergency contacts, in the form Schedule 12 prescribes. A manifest is not a bigger register; its stated purpose is to hand emergency services organisations what they need to fight an incident at your site. The code lists notifying the regulator of manifest quantities among the same set of duties, and under regulation 361 the workplace emergency plan must be given to the primary emergency services organisation, which must then be revised in line with any recommendations that organisation makes about its effectiveness. That last step makes the fire brigade a reviewer of your paperwork, which is exactly the point. Our emergency-plan story covers what regulation 43 requires the plan itself to contain.
The rule on every rung: keep incompatibles apart
The code's control-measures chapter treats segregation as a first-order control, not housekeeping. Hazardous chemicals should be physically separated from anything incompatible, by distance, by barriers, or both, and the code prefers separation distances that work without extra controls. On shelving, the rule is vertical as well as horizontal: chemicals should not be stored above or below incompatible chemicals, or anywhere they could contaminate food, food packaging or personal-use products. The SDS's storage section is where incompatibilities are declared, which is one more reason rung one is load-bearing: mixed acid and base stores, or oxidisers shelved over cardboard, are the failure the whole system is built to prevent. For flammable and combustible liquids the code points to AS 1940, the storage and handling standard, for separation and store design detail (the standard itself is paywalled; the code names it as the reference).
Where does silica sit in all this? Respirable crystalline silica is a hazardous chemical with a workplace exposure standard of its own, and the engineered-stone ban that came with it is its own story on this masthead. The storage ladder above is about chemicals in containers; the exposure-standard duties run in parallel whatever the quantity.
What to check this week
The code's own sequence is the audit: walk the store and list what is actually there against the register; pull five SDSs and check they are the Australian manufacturer's or importer's current version; add up the litres per hazard class against the table above; and if you are anywhere near a placard quantity, count what arrives in your busiest week before deciding you are under it. The storage duty does not switch off when the chemical is not in use; stored chemicals are the code's central case, because that is where quantity accumulates.
Sourcing note
All duties, thresholds and quoted requirements are taken from the model Code of Practice: Managing risks of hazardous chemicals in the workplace (Safe Work Australia, June 2023 edition, 115 pages), read in full on 8 July 2026, with regulation numbers as the code states them. The placard and manifest quantities are Schedule 11 of the model WHS Regulations as reproduced in the code's Appendix D; jurisdictions enact the model regulations locally, so confirm your regulator's enacted schedule before relying on a threshold. The code's worked case studies are illustrative examples, not real incidents, and none is cited here as an event.