Major Hazard Facilities in Australia: most businesses think it doesn't apply to them. Some of them are wrong.

When people think about Major Hazard Facilities, they picture refineries. Gas terminals. Chemical manufacturing plants. Large industrial operations with hazard diamonds on the perimeter fence and safety cases on the regulator's desk.

That picture is not wrong — those sites are MHFs. But it creates a blind spot. Because the MHF framework in Australia is not defined by what a site looks like. It is defined by what a site stores, and how much of it. Specifically, whether the quantities of scheduled chemicals present at the site reach the threshold quantities set out in the relevant regulation for each jurisdiction.

And the notification obligation does not start at the MHF threshold. It starts at 10 per cent of it.

What is a Major Hazard Facility?

A Major Hazard Facility is generally a site where scheduled chemicals are present, or likely to be present, at quantities that meet the relevant MHF threshold — or a site that the regulator determines to be an MHF after assessment. The scheduled chemicals include substances such as flammable gases, flammable liquids, toxic substances, oxidisers, and explosives — many of which are found in warehousing, distribution, agriculture, mining services, and manufacturing operations across Australia.

The MHF framework exists because these sites present a potential for a major incident — one that could cause significant harm to people, property or the environment beyond the site boundary. The framework is designed to protect not only the workers handling those chemicals on site, but the surrounding community — neighbouring businesses, residential areas, and members of the public who may be affected by a major incident without any direct connection to the operation. The compliance regime that applies to a confirmed MHF is fundamentally different from the manifest-level obligations most businesses manage. It includes a formal Safety Case, a Safety Management System, a comprehensive safety assessment, regulator review and licensing, ongoing oversight, and periodic review and audit obligations — as well as potentially significant capital requirements.

"The MHF framework exists because some chemical risks cannot be assessed by quantity alone. Its purpose is to protect workers and the surrounding community where scheduled chemicals are present, whether as products or ingredients. That is why reporting at 10% matters — it gives the regulator visibility early, because MHF determination depends on the chemical, the quantity, the operations, and the site's location, including what sits around it."

— Andrew Hahn, Co-founder and DG Expert, DGXprt

That regime is not what this post is about. This post is about the businesses that have not yet asked the question.

The notification trigger most businesses don't know about

Here is where many businesses are caught out. In most Australian jurisdictions, the obligation to notify the regulator does not begin when you cross the MHF threshold. It begins when stored quantities reach, exceed, or are likely to exceed the relevant 10 per cent notification trigger for the scheduled chemical. The exact wording and notification mechanism varies by jurisdiction — but the practical effect is the same: if you are at 10 per cent or more of the threshold, you may have a notification obligation that has not been met.

That 10% trigger is a notification obligation — not an MHF designation. Crossing it does not make you an MHF. But it does mean you are required to notify the relevant regulator within the timeframe set by your jurisdiction — who will then assess whether an MHF determination is warranted. Notification timeframes vary: in NSW, for example, you must notify SafeWork NSW as soon as practicable, and in any case within three months, of becoming aware. Victoria requires notification within 30 days. Always confirm the applicable timeframe with your state regulator.

The reason notification starts at 10 per cent rather than at the full threshold is that MHF determination is a regulatory judgement — not just a calculation. The regulator considers the chemical and its properties, the quantity stored, the nature of the operations on site, and the location and context of the facility. A site in close proximity to residential areas, schools, hospitals, or other workplaces presents a different risk picture from an equivalent inventory in an isolated industrial location. By starting the notification process at 10 per cent of threshold, the framework gives the regulator the opportunity to make that assessment before the site reaches MHF territory.

For businesses storing large quantities of common dangerous goods — such as LPG, ammonia, oxidising agents — that 10 per cent threshold is reachable without the site looking anything like a traditional MHF.

It varies by state — significantly

The MHF framework in Australia is not nationally consistent. Each state and territory has its own legislation, its own scheduled quantity lists, and its own regulatory authority. Understanding your MHF position requires knowing which framework applies to your site — not just generally, but specifically.

Some of the key differences:

Note: The ACT uses Schedule 15 threshold quantities but applies different internal table numbering (Tables 15.6.1–15.6.3) under its own drafting convention. WA operates under standalone DG safety legislation with no WHS chapter structure. Always confirm current legislation and applicable schedule references with your state or territory regulator.

The scheduled chemical quantities that trigger MHF notification also differ between jurisdictions. A quantity of a particular substance that sits comfortably below the MHF notification threshold in one state may exceed it in another. For multi-site operators, this means the question cannot be answered once and applied everywhere.

Why this is genuinely difficult to assess

This is where the real complexity sits — and why MHF threshold assessment is not something that can be reliably done in a spreadsheet by someone working through SDS documents.

It is based on specific named chemicals, not DG classes

You cannot work backwards from a manifest DG class alone. The MHF schedule uses specific chemical identities and hazard categories — a different exercise entirely.

Manifest compliance is built around DG classes and packing groups. Class 3 flammable liquid, Packing Group II. That classification drives your threshold calculation.

MHF schedules are not simply DG manifest tables. They include specific named chemicals as well as classes, types and categories of hazardous chemicals — meaning you cannot reliably work backwards from a manifest DG classification alone. A substance classified as Class 8 corrosive for manifest purposes has no corresponding category in the MHF hazard category tables — working from the DG class alone would suggest it isn't scheduled at all.

Bromine, for example, is a Class 8 corrosive for transport purposes, yet it appears as a named chemical in the MHF schedule with a threshold of 100 tonnes. The assessment requires checking each substance specifically against both the named chemicals list and the hazard category tables in the relevant jurisdiction.

Hazard categories and toxicity values change the calculation

Two substances both classified as Class 6.1 Toxic can have completely different MHF thresholds. Packing group is not a reliable proxy.

For toxic and harmful substances, MHF thresholds are not uniform across a DG class. They vary by the specific hazard category of the substance — which is determined by values such as LC50 and LD50 from toxicological data. Two substances both classified as Class 6.1 Toxic can have completely different MHF thresholds because their toxicity profiles are different.

A common error — specifically flagged in the Safe Work Australia notification guide — is using packing group as a proxy for MHF toxicity category. Some very toxic chemicals may have a different packing group from what a simple MHF toxicity assessment might suggest, so packing group is not a reliable proxy for MHF hazard category. The correct approach uses the LC50 and LD50 values from the SDS toxicological data section, not the transport classification.

That toxicological data lives in the SDS. Extracting it, interpreting it correctly, and mapping it to the relevant hazard category in the MHF schedule requires someone who knows what they are looking for and what it means. It is not a task for a generalist reading an SDS for the first time.

Mixtures add another layer: what is in the product?

What matters is the quantity of the scheduled chemical within the mixture, not the total product quantity.

Many products stored on site are not pure substances — they are mixtures. And for MHF purposes, what matters is often not the total quantity of the mixture, but the quantity of the scheduled chemical contained within it.

A product that contains 30 per cent of a scheduled toxic substance requires the calculation to be performed on the quantity of that component — not the total product volume. That concentration data comes from the SDS composition section. If the SDS is incomplete, uses a range rather than a specific figure, or does not disclose the concentration of a confidential ingredient, the calculation cannot be completed accurately.

All of it depends on SDS data quality

If the SDS data is wrong or incomplete, the MHF calculation built on it is wrong.

Every step of an MHF threshold assessment starts with SDS data. The chemical identity, the hazard classification, the toxicological values, the composition of mixtures — all of it comes from the SDS. And based on DGXprt's SDS review data, more than 40 per cent of SDSs assessed fail compliance on first review — out of date, missing required sections, or using pre-GHS formats that do not contain the data fields needed for this level of analysis.

An MHF threshold assessment built on non-compliant SDS data produces an unreliable result. The calculation may look complete. The conclusion it reaches may be wrong.

What this looks like in practice, without any automation

Doing an MHF threshold assessment manually means: pulling the relevant scheduled chemical list for each state your sites operate in; cross-referencing every chemical in your inventory against that list by name, CAS number and chemical group; sourcing and reading the SDS for each substance to extract toxicological values and mixture compositions; applying the aggregation rules; and comparing the result against jurisdiction-specific thresholds.

Who should be asking the question?

This is not a question every business storing dangerous goods needs to answer. If you are below manifest threshold, or only just above it with small quantities of common goods, MHF territory is most likely not relevant to your situation.

You should be asking this question if any of the following apply:

• You store large quantities of flammable liquids, flammable gases, toxic substances, or oxidisers — particularly in bulk
• Your site has grown in scale over time and your compliance position has not been formally reassessed
• You operate in industries such as chemical distribution, fuel storage, agricultural chemicals, refrigerants, or industrial gases
• You store quantities that are a significant multiple of your manifest threshold — not just above it, but substantially above it
• You have multiple sites and have not assessed whether aggregate quantities across sites are relevant to MHF calculations

Why knowing early matters — and why some businesses actively choose to stay below

Here is something that rarely gets said plainly: many businesses operating at or near manifest level make a conscious decision that they do not want to become an MHF.

That is a legitimate and rational business decision. But it only works if you know where the boundary is and how close you are to it. A business that discovers it has crossed the 10 per cent notification threshold — or the MHF threshold itself — during a regulator visit has lost the ability to make that choice. It is already inside a compliance regime it did not plan for.

The businesses that manage this well are the ones that know their threshold position in real time. When they consider adding a new product line, expanding storage capacity, or taking on a new customer's inventory, they know what the DG implications are before they commit. They can see whether a proposed change would push them closer to MHF territory — and they can make an informed decision about whether that trade-off is worth it.

For some, the answer is yes — the commercial opportunity is worth the compliance investment. For others, the answer is to restructure storage, consider how inventory is managed across locations, or make decisions about which product lines are worth carrying — taking into account that what constitutes a single facility for MHF purposes is itself a regulatory assessment, not simply a question of physical separation.

Neither answer is wrong. What is wrong is not knowing.

What our customers tell us

"We want to avoid MHF like the plague."

This is a direct quote from more than one DGXprt customer. Not because they are cutting corners on safety — but because MHF designation changes your business in ways that extend well beyond compliance. The cost of a Safety Case. The resource commitment of independent audits. The operational constraints that come with ongoing regulator engagement. The capital requirements for fire protection systems. For a business that is not already structured to absorb those obligations, the impact is significant. Knowing your position before you are inside that regime gives you the option to manage it. Not knowing means you are reacting rather than choosing.

What MHF compliance actually involves

This is important context for anyone approaching this territory. MHF compliance is not an extension of manifest compliance. It is a completely different regime.

A site that is formally designated as an MHF is required to prepare a Safety Case — a formal document demonstrating that all major incident hazards have been identified, that risks are controlled to acceptable levels, and that the site has the systems and capability to manage those risks on an ongoing basis. The Safety Case must be submitted to the regulator and is subject to regulator assessment, review and audit requirements.

MHF designation also involves ongoing regulator engagement, mandatory incident reporting, periodic review of the Safety Case, and potentially significant infrastructure requirements. It is not a compliance exercise — it is a sustained operational commitment.

This is why knowing your position before you cross the threshold matters. The time to understand whether you are approaching MHF territory is before a regulator assessment tells you that you are already in it.

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