Chemical Bunding Requirements & Regulations in Australia: How to Stay Compliant

If your workplace stores or handles hazardous or dangerous chemicals, such as acids, solvents, oxidisers, corrosives, or any other dangerous good, secondary containment isn't a nice-to-have; it’s a must. Under Work Health and Safety Regulation 357, you have a legal duty to contain any spill or leak before it leaves your site, and state EPA legislation sits on top of that. Get it wrong, and a single drum failure can reach a stormwater drain, and the clean-up cost and EPA liability land on you.

The catch with chemicals is that "compliant" looks different for an acid than it does for a flammable solvent or an oxidiser. The right bund depends on what you're storing, how much, and what else is sitting next to it. This guide works through the six questions that decide exactly what your site needs, from what you're storing through to the right product.

 

Which chemical are you storing?

Before you can choose the right bund, you need one piece of information: which chemical you're storing, or about to store. That single answer drives everything else: which Australian Standard applies to you, how much your bund has to hold, and what it can be made from.

In Australia, every hazardous chemical is sorted into a "dangerous goods (DG) class" based on its main hazard, and each class has its own storage standard. You don't need to know the class yourself; find your chemical in the list below, or check section 14 of its Safety Data Sheet (SDS), and you'll have both your class and the standard that applies.

• Acids and alkalis (hydrochloric, sulphuric and nitric acid; caustic soda and similar cleaning chemicals): these are Class 8 corrosives, covered by AS 3780.

• Petrol, solvents, acetone, thinners: Class 3 flammable liquids, covered by AS 1940:2017.

• Diesel, oils, kerosene: C1 / C2 combustible liquids, also under AS 1940:2017.

• Hydrogen peroxide, pool chlorine, sodium hypochlorite (bleach): Class 5.1 oxidising agents, covered by AS 4326.

• Many pesticides and some industrial solvents: Class 6.1 toxic substances, covered by AS/NZS 4452.

Once you've matched your chemical to its class, the rest of this guide walks you through what that means in practice: the capacity you need, the material to choose, and what your chemical can safely sit next to. If your product isn't on the list or you're not sure, its SDS is the definitive source, and our team can help you identify it.

 

What are you storing it in, and how much?

How much your bund needs to hold comes down to one simple test. A bund has to catch a worst-case spill, so the rule is to take the bigger of these two numbers:

• 110% of your largest single container, or

• 25% of everything stored in that bund, added together.

Work out both, then use the higher one. That is the minimum your bund has to hold.

A quick example. Say you store one 205 L drum. 110% of 205 L is about 226 L. There's only one container, so the 25% figure doesn't come into it. Your bund needs to hold at least 226 L.

What if you have more than one container? Say you have two 205 L drums:

• 110% of the largest drum (205 L) = 226 L

• 25% of both drums combined (410 L) = about 103 L

The bigger number wins, so 226 L is still your minimum. The rule assumes only one container is likely to fail at a time, which is why your largest single container, not the total, usually sets the figure.

The mistake almost everyone makes. What counts is how much the bund holds with your containers sitting inside it, not when it's empty. Picture an open tray rated at 250 L: stand a couple of drums in it and they take up room, so it might only hold around 200 L of actual spill. The fix is simple: ask for the net sump capacity (the real, usable figure), not the size of the empty tray. Quality bunded pallets quote the sump capacity below the grate, which is exactly the figure you want.

One heads-up on chemicals. The 110% / 25% test is the general rule, but a few chemical classes are worked out a little differently in their Australian Standard. In particular, flammable and combustible liquids need extra room set aside for fire-fighting water, on top of the spill volume itself. You don't need to memorise any formulas. Just match the capacity to your class, or call us and we'll size it for you.

For drum storage, a single 205 L drum needs at least 226 L of containment.

• Premium 2 Drum Bunded Pallet: 230 L bund capacity, holds 2 × 205 L drums, SWL 500 kg, removable grate with drain outlet. Chemical-resistant polyethylene, rated for acids and corrosives. $529 inc. GST.

For IBC storage, a 1,000 L IBC needs a bund that holds at least 1,100 L. Two IBCs still only need 1,100 L, because the largest single container again sets the number.

• Single IBC Bunded Pallet: 1,300 L sump capacity, suits 1 × 1,000 L IBC, static load 3,600 kg, 2-way forklift entry, dual grates and drain outlet. Australian-made HDPE, UV stable for outdoor use. $1,864 inc. GST.

 

Can chemicals share a bund?

Putting incompatible chemicals in the same bund, or even too close together, can trigger a violent reaction, generate heat, or release toxic gas if they leak and mix.

The combinations to keep apart:

• Acids and bases (alkalis): react violently and generate heat, even though both may be Class 8.

• Oxidisers and flammables or organics: oxidisers (Class 5.1) feed fire; stored with solvents, fuels, or even cardboard, they sharply raise fire and explosion risk.

• Acids and oxidisers: can release toxic or corrosive gases.

• Acids and cyanides or sulphides: can release highly toxic gas.

A common and costly mistake is assuming two chemicals can share a bund because they're the same DG class. Acids and alkalis are both Class 8, but they are mutually incompatible. Where you store incompatible classes, AS/NZS 3833 requires segregation: by distance or a physical barrier, with each group on its own bund or compound.

Used or waste chemical should always have its own clearly labelled, separate bund. Contamination can change its hazard profile and complicate disposal, so keep it isolated from new product.

 

What does your bund need to be made of?

With chemicals, the bund material is part of compliance, not just durability. If the chemical attacks the bund, the containment fails, and a failed material is treated as non-compliant. Match the material to the substance:

• Polyethylene / HDPE: the workhorse for most chemical storage. Resists acids, alkalis, salts, oils, and hydrocarbons, which makes it ideal for corrosives (Class 8) and general chemical use. Best Bunding's drum and IBC bunded pallets are HDPE.

• PVDF: a step up in chemical resistance for more aggressive substances; the rigid bund range is built from it.

• PVC: good general resistance for short-term and portable containment.

The practical takeaway: poly and PVDF cover the large majority of chemicals, corrosives especially. If you're storing Class 3 flammables, confirm the fire-resistance requirements with a supplier before you buy; the material that's perfect for acid may not satisfy AS 1940 for a flammable solvent.

 

Where, and is it permanent or temporary?

Location and duration decide the product.

For fixed, indoor storage, a bunded pallet (drum or IBC) on a sealed, impervious floor is the standard compliant solution. For semi-permanent storage where floor space is tight, a rigid bund builds the retention volume into the walls, with no external legs to get in the way.

• Rigid Bunds: heavy-duty PVDF, retention volume built into the walls, space-saving with no external legs, no assembly required. Well suited to ongoing chemical storage. From $594 inc. GST.

For temporary or changing sites, such as maintenance, short projects, or anywhere you need vehicle access, portable options fold flat and deploy fast.

• Collapsible Bunds: PVC with 300 mm self-supporting sidewalls and folding legs that drop for forklift access. Lightweight and portable for temporary worksites. From $850 inc. GST.

• PVC SpillBund: low-profile 100 mm memory-foam sidewalls that spring back after being driven over. No assembly, ideal for high-traffic workshops and maintenance areas. From $262 inc. GST.

Outdoors, rainwater is the issue: water fills the bund, eats into your spill capacity, and once it's mixed with chemical residue you can't simply discharge it to a drain. For ongoing outdoor storage, use a covered setup wherever practical.

One compliance point that matters: AS 1940 treats portable bunding as unsuitable for fixed, ongoing storage. If the chemical sits in one place day after day, you need a permanent bund, not a collapsible one.

 

Could a spill reach a drain or waterway?

This is the first thing a regulator assesses. Stormwater drains, unsealed ground, waterways, and neighbouring properties are all sensitive receptors, and the closer your storage sits to one, the higher the scrutiny and the greater the consequences if something goes wrong.

If your chemicals are near a floor drain or grate, a sealed bund with proper liquid management is essential. And note the distinction regulators draw: a spill kit cleans up after a spill, but it does not contain one. A spill kit is a sensible complement to bunding, never a substitute for it.

 

Which state regulations apply to you?

AS standards set the technical baseline nationally, but each state's EPA and WHS regulator layer their own requirements on top, and the stricter requirement always wins.

New South Wales regulates higher-risk operations through the POEO Act and EPA licensing. Victoria's Environment Protection Act 2017 imposes a general environmental duty: you must proactively prevent harm, not just react after a spill. Queensland administers chemical storage through the WHS Act and the state EPA, with local council overlays in urban areas. South Australia has one of the more prescriptive regimes, with EPA SA's bunding and spill management guidance addressing chemicals directly. Western Australia licenses dangerous goods storage above set thresholds under the Dangerous Goods Safety Act. If you're unsure whether your volumes trigger a licence or registration, check with your state regulator before you set up storage.

Disclaimer: Requirements vary by state, industry, chemical class, volume, and site conditions. This guide is general information based on the relevant Australian Standards and publicly available state EPA guidance. Confirm your specific obligations with your relevant state regulator or a qualified environmental/WHS adviser.

 

How do you keep it compliant?

A bund that was compliant on day one can quietly fall out of compliance. Check three things on a routine basis:

• Physical integrity: cracks, failed seals, or gaps at joints. Any breach is a containment failure.

• Net capacity: re-check whenever you add or change containers, or if liquid has collected in the sump and reduced usable volume.

• Liquid management: clear and correctly dispose of anything that collects in the sump, and test before discharging outdoor rainwater.

There's no nationally mandated inspection interval, but a monthly visual check plus a documented annual inspection is sound practice. Keep a simple maintenance log; if your site is ever audited, it's your evidence of active management rather than a set-and-forget approach.

July 2026