A 1940 High Court Case With a 2026 Workplace Message: Adelaide Chemical & Fertilizer Co Ltd v Carlyle

Why “that’s how we’ve always done it” is not an answer to workplace risk

Case: Adelaide Chemical & Fertilizer Co Ltd v Carlyle [1940] HCA 44 Court: High Court of Australia Subject: Workplace injury, dangerous substances, duty of care, unsafe equipment, causation and responsibility for foreseeable risk.

Some cases survive because of a technical rule. Others survive because the principle they express remains fundamentally relevant decades later.

Adelaide Chemical & Fertilizer Co Ltd v Carlyle is one of those cases.

Decided by the High Court of Australia in 1940, Carlyle was not an industrial relations decision in the modern Fair Work Act sense. It was a negligence and fatal-injury case arising from the supply of sulphuric acid. But viewed through a modern workplace lens, it deals with issues that sit squarely at the intersection of work health and safety, employment relations, workers' compensation, supply-chain responsibility and the allocation of workplace risk.

Its central proposition remains remarkably contemporary:

The greater the danger, the more exacting the precautions that reasonable care demands.

That principle now sits comfortably beside Australia's modern statutory WHS framework, where risk is assessed by reference to both the likelihood of an incident and the seriousness of the harm that could follow.

Perhaps more importantly, Carlyle delivers another message that should resonate with every employer, PCBU, manager and worker today:

A dangerous system does not become safe merely because people have used it that way for years.

A 1940 High Court Case With a 2026 Workplace Message: Adelaide Chemical & Fertilizer Co Ltd v Carlyle

What happened in Carlyle?

Leslie Morton Carlyle worked for a herd-testing association in South Australia. His work involved the use of concentrated sulphuric acid. The acid was supplied by Adelaide Chemical & Fertilizer Company Limited under an arrangement involving the South Australian Department of Agriculture.

Importantly, Adelaide Chemical was not Carlyle's employer. It was the manufacturer and supplier of the sulphuric acid.

That distinction becomes highly significant when considering the case in a modern environment involving contractors, labour hire, host employers, manufacturers, suppliers and multiple PCBUs.

The sulphuric acid was supplied in large earthenware jars. Each contained approximately three gallons of acid. The acid alone weighed about 56 pounds and, with the jar itself weighing around 19 pounds, the total load was approximately 75 pounds.

The jars were commonly used and had been obtained from a reputable manufacturer. There was evidence that they had been tested and that relatively few had previously broken.

But there was also disturbing evidence about their physical characteristics.

Experiments demonstrated that when jars containing liquid of approximately the same weight as the sulphuric acid were tilted and allowed to fall approximately nine inches, they broke. That was particularly serious because the substance inside them was highly corrosive.

On 31 March 1939, Carlyle attended the company's delivery platform to collect two jars.

While attempting to lift one of them from the platform and move it to his vehicle, the jar broke. Sulphuric acid poured over his legs and body. He rushed inside, removed his trousers and attempted to wash the acid from himself.

His wife, who was nearby, followed him.

Carlyle subsequently received hospital treatment. An infection developed and he suffered streptococcal septicaemia. He later died.

His widow brought proceedings against the supplier.

The trial judge found both that the particular jar was defective and that the type of jar generally being used was unsafe and dangerous for the purpose for which it was being supplied.

The High Court dismissed the company's appeal.

The real importance of the High Court's decision

The importance of Carlyle is not that the High Court imposed absolute liability whenever a dangerous substance is involved.

It did not.

That qualification matters.

The Court's reasoning was that the applicable standard remained reasonable care. But what constitutes reasonable care changes according to the nature and magnitude of the risk.

That is where Carlyle becomes extraordinarily relevant to contemporary workplace safety.

Starke J recognised that sulphuric acid and the containers in which it was supplied involved an obvious and potentially grave danger. His Honour explained that where the consequences are sufficiently serious, the required diligence may become so stringent that it approaches what was described as:

“practically to a guarantee of safety”.

The uploaded case report also records how this proposition was later taken up in Burnie Port Authority v General Jones Pty Ltd [1994] HCA 13: the legal standard remains reasonable care, but the level of care demanded increases with the magnitude of the danger.

Dixon J expressed the concept particularly powerfully:

“the reasonable care required by the law means a standard of diligence growing in strictness as the danger increases”.

That is probably the most important sentence in Carlyle for the modern workplace.

Reasonable care is not a fixed standard

It is tempting to think of “reasonable care” as a single standard.

Carlyle demonstrates why that is wrong.

The precautions reasonably required when moving boxes of stationery are plainly different from those reasonably required when handling sulphuric acid, explosives, industrial chemicals, high-voltage equipment, heavy machinery or other hazards capable of producing catastrophic injury.

The duty remains one of reasonable care, but reasonableness is calibrated to the risk.

Australia's modern model WHS framework now expresses essentially the same risk-based concept in statutory language. Section 17 of the current Model WHS Bill requires risks to be eliminated so far as reasonably practicable and, where elimination is not reasonably practicable, minimised so far as reasonably practicable. Section 18 requires consideration of the likelihood of the hazard occurring, the degree of harm that could result, what is known or ought reasonably to be known about the risk and available controls, and the availability, suitability and cost of those controls.

That is strikingly consistent with the reasoning underlying Carlyle.

A low-probability event cannot simply be dismissed where its potential consequence is catastrophic.

“We have always done it this way” is not a safety defence

One of the strongest modern lessons from Carlyle concerns industry custom and established practice.

The company relied substantially upon the fact that these types of jars were ordinarily used and that large numbers had apparently been handled without incident.

That did not determine the case.

McTiernan J's reasoning is especially important in this respect. Evidence that an unsafe practice is widespread may be relevant, but it does not conclusively establish that the practice is reasonable.

An entire industry can become accustomed to an unsafe method.

Workers can also become conditioned to accepting unnecessary risk because “that's how the job has always been done”.

That issue continues to arise today in industries involving manual handling, transport, construction, mining, corrections, health care, agriculture, manufacturing and warehousing.

The modern question should not simply be:

“Has anyone been seriously injured doing this before?”

The better question is:

“What could reasonably happen, how serious would the consequences be, and what can reasonably be done to prevent it?”

That is very close to the modern statutory “reasonably practicable” analysis.

The worker is not the safety control

Another highly contemporary aspect of Carlyle is the Court's refusal to transfer responsibility for a dangerous system onto the worker.

The jars were heavy. They contained an exceptionally dangerous chemical. Their physical characteristics meant they could fracture when subjected to foreseeable movement or impact.

It would have been easy to frame the accident simply as:

“The worker should have handled the jar more carefully.”

The Court did not accept that as the answer.

That distinction is critical to modern safety management.

A system of work should not depend entirely upon every worker behaving perfectly, every second of every day.

Human beings make mistakes. They lose grip. They misjudge distances. They become fatigued. They misunderstand instructions. They take shortcuts. Equipment slips.

Modern risk control therefore requires systems to be designed, so far as reasonably practicable, to prevent a foreseeable human error from becoming a catastrophic injury.

The continuing significance of Carlyle is illustrated by later authority reproduced in the uploaded report. In Baker v Morona [2022] VSC 660, the Court referred to Carlyle when explaining that manufacturers dealing with very dangerous machinery must take account of the possibility that users may inadvertently or carelessly fail to take proper care for their own safety.

That is a systems-safety principle, not merely a negligence principle.

From supplier liability in 1940 to shared WHS responsibility today

This may be the most interesting part of Carlyle when viewed through the modern industrial relations landscape.

Adelaide Chemical was not Carlyle's employer.

Nevertheless, its conduct exposed a worker to risk.

Today, Australian WHS regulation deliberately extends well beyond the traditional employer-employee relationship.

The current Model WHS framework provides that more than one person may concurrently owe a duty and each duty holder retains responsibility to the extent of their ability to influence or control the matter.

The model provisions also impose specific duties upon manufacturers and suppliers of plant, substances and structures. Manufacturers must, so far as reasonably practicable, ensure relevant products are manufactured without risks to people who use, handle, store or undertake reasonably foreseeable activities involving them, together with testing and information obligations. Suppliers are subject to corresponding obligations concerning the safety of the plant, substances or structures they supply.

The connection with Carlyle is obvious.

The modern workplace cannot always compartmentalise responsibility by saying:

“That person isn't our employee.”

A labour-hire host, contractor, principal contractor, designer, manufacturer, importer, supplier or other business may have its own responsibilities arising from its influence over the risk.

Safe Work Australia also makes clear that the model laws themselves only become legally binding when separately enacted by the Commonwealth, states and territories, so the precise statutory position must always be checked in the relevant jurisdiction. (Safe Work Australia)

The meaning of “worker” has also moved beyond traditional employment

Industrial relations has changed enormously since 1940.

Work is now routinely performed through labour-hire arrangements, subcontracting chains, outsourcing, casual engagement and other non-traditional structures.

The current model WHS definition reflects that reality. A “worker” includes not only employees but contractors and subcontractors, employees of contractors, labour-hire workers, outworkers, apprentices, trainees, work-experience students and volunteers.

That makes the structure of Carlyle surprisingly modern.

The case involved a worker suffering harm from a hazard introduced by an entity other than his direct employer.

Eighty-six years later, that type of problem is commonplace.

The legal architecture has become considerably more sophisticated, but the fundamental question identified by Carlyle survives:

Who created, supplied, controlled or could reasonably have eliminated the risk?

Worker consultation and the right to challenge unsafe work

Modern industrial relations also gives workers a much more formal role in the management of workplace risk.

Consultation with workers is a legal requirement under the model WHS framework. Safe Work Australia describes consultation as an essential component of managing workplace health and safety. (Safe Work Australia)

The model framework also provides a right for a worker to cease or refuse work where the worker has a reasonable concern that performing it would expose them to a serious risk from an immediate or imminent hazard. Health and safety representatives may also direct relevant workers to cease unsafe work in prescribed circumstances.

That represents an important development from the industrial environment reflected in Carlyle.

Workers are not merely the recipients of workplace safety decisions. Modern industrial relations recognises them as participants in identifying and challenging risk.

That is why employers who characterise every safety complaint as “insubordination”, “negativity”, “refusal to follow directions” or a “performance issue” should proceed very carefully.

Safety complaints can also become Fair Work disputes

This is where WHS and industrial relations increasingly intersect.

The current Fair Work Act 2009 compilation in force from 7 July 2026 continues to prohibit adverse action because a person has, exercises or proposes to exercise a workplace right. (Federal Register of Legislation)

Section 341 provides that workplace rights can include an entitlement or responsibility under workplace law, participation in processes under workplace law, and an employee's ability to make certain complaints or inquiries, including complaints or inquiries in relation to their employment. (Federal Register of Legislation)

That does not mean every disagreement about workplace safety automatically establishes a general protections contravention. The particular right relied upon, the alleged adverse action and the reasons for that action remain fact-specific matters.

But it does mean that a serious safety dispute can rapidly develop into more than a WHS issue.

For example, where a worker raises a legitimate concern about dangerous equipment or an unsafe system and is subsequently disciplined, disadvantaged or dismissed, the circumstances may require examination through both the applicable WHS regime and the Fair Work general protections framework.

That is very much part of the contemporary industrial relations landscape.

Carlyle and causation: the original injury does not exist in isolation

Carlyle is also valuable in workers' compensation and injury matters because the immediate burns were not themselves the final cause of death.

Carlyle subsequently developed streptococcal septicaemia.

The company argued, in substance, that the later infection represented a separate intervening cause.

The High Court rejected that approach. The sulphuric acid burns produced the physical injury through which the later infection occurred. The subsequent medical development was not treated as so independent and disconnected that the causal chain was broken.

The uploaded report shows the principle continuing to appear in later compensation-related reasoning, including Barraclough v WorkCover Queensland [2012] QDC 321, where Carlyle was referred to in considering whether a subsequently developing condition was a new injury or a consequence of the original injury.

The precise test in any contemporary workers' compensation dispute depends upon the legislation applying in the particular jurisdiction. But Carlyle remains useful conceptually: an injury does not necessarily stop being work-related merely because its medical consequences develop later or become more serious over time.

A case about evidence as well as safety

There is another important aspect of Carlyle that should not be overlooked.

Immediately after the accident, while Carlyle was attempting to wash the acid from himself, his wife asked what had happened. He told her, in substance, that he had taken hold of the jar, tilted it to get his other hand underneath, and that the top appeared to come away in his hand.

The admissibility of that statement produced substantial judicial discussion about what was then described as res gestae and the treatment of spontaneous or contemporaneous statements.

Dixon J took a narrower view of that particular statement, regarding it as a narrative of an event already completed rather than an integral part of the occurrence. That part of Carlyle went on to be considered repeatedly in Australian evidence law.

For workplace advocates, however, there is a practical modern lesson independent of the technical evidence doctrine:

record the evidence while it is fresh.

An incident report made immediately after an event, photographs, CCTV, messages, contemporaneous complaints, witness accounts, medical attendances, hazard reports and previous notifications of the same risk may later become enormously important.

A workplace investigation conducted months later cannot recreate evidence that was never preserved.

Why Carlyle still matters in 2026

The industrial relations system has changed beyond recognition since Leslie Carlyle collected those jars of sulphuric acid in 1939.

We now have comprehensive statutory WHS regimes, specialist safety regulators, workers' compensation systems, the Fair Work Act, general protections, health and safety representatives, consultation obligations and formal risk-management methodologies.

Yet the underlying industrial problem in Carlyle has not changed.

Businesses still sometimes normalise dangerous practices because an accident has not happened recently.

Workers are still sometimes blamed for failing to compensate for poor systems.

Businesses still sometimes assume that compliance with industry custom establishes safety.

Responsibility is still sometimes pushed down contracting and supply chains.

And serious incidents are still sometimes followed by an investigation that begins with the worker's conduct rather than asking whether the system should ever have allowed a single mistake to produce catastrophic consequences.

Carlyle reminds us that this is the wrong starting point.

The modern primary WHS duty requires, so far as reasonably practicable, safe work environments, safe plant, safe systems of work and the safe use, handling and storage of substances, together with appropriate information, instruction, training and supervision. (Safe Work Australia)

The legal language has evolved.

The principle has not.

The enduring principle

The enduring lesson from Adelaide Chemical & Fertilizer Co Ltd v Carlyle is therefore broader than sulphuric acid or defective earthenware jars.

It is a principle about how workplace risk should be allocated.

The person exposed to the hazard should not automatically carry responsibility for overcoming defects in the system that created the hazard.

The more devastating the foreseeable consequence, the less satisfactory it becomes to rely upon warnings, experience, worker vigilance or historical accident rates as substitutes for effective controls.

And an unsafe practice does not become reasonable simply because it is customary.

That makes Carlyle much more than an historical negligence case.

It is an early Australian articulation of a concept now embedded throughout contemporary workplace safety:

As the danger increases, the standard of precaution must rise with it.

For employers, PCBUs, managers, workers, health and safety representatives and workplace advocates, that remains as relevant in 2026 as it was when the High Court handed down its decision in 1940.

MYUNION | Employment, Workplace and Human Rights Advocacy

This article provides general information and industrial relations/WHS commentary. It is not legal advice.

WHS, workers' compensation and employment legislation varies between jurisdictions and individual circumstances require assessment.