Section 2 of the Health and Safety at Work etc Act 1974 (HSWA) provides that:

"It shall be the duty of every employer to ensure, so far as is reasonably practicable, the health, safety and welfare at work of all his employees."

Section 3 of HSWA provides that:

"It shall be the duty of every employer to conduct his undertaking in such a way as to ensure, so far as is reasonably practicable, that persons not in his employment who may be affected thereby are not exposed to risks to their health and safety."

These sections have caused much angst as their wide ambit makes prosecution for a breach of them difficult to defend.

If the prosecution establish to the criminal standard of proof (i.e. near certainty) that there was a risk to employees or others, the burden of proof shifts to the Defendant to establish to the civil standard of proof (i.e. slightly more likely than not) that it did all that was reasonably practicable to ensure the safety of its staff/others.

Over the years it has proved difficult to persuade the courts that, particularly when there has been an accident, everything reasonably practicable has been done. As a result, defence tactics have shifted from trying to prove a reasonable practicality defence, to challenge the level of risk which ought to prompt all reasonably practicable steps being taken. After all, if there isn't a "risk" about which there is a need to do anything, the fact that it might have been reasonably practicable to do something about it doesn't even arise.

Even though section 2 doesn't mention risk specifically, it has been made very clear by the Court that the employer's duty is just as much concerned with the risk to the health, safety and welfare of employees as section 3 is expressly concerned with the risk to others.

The following key cases plot the evolution of the argument:

  • In R -v- Board of Trustees of the Science Museum [1993], prosecution was in the context of bacteria capable of causing Legionnaire's disease being discovered in water systems in the museum. There was no proof of harm but Steyn LJ said of the word "risks" in section 3, that it, "conveys the idea of a possibility of danger." Significantly (as it later turned out) the judgment also referred to "the imperative of protecting public health and safety"
  • Eleven years later the definition of risk as a "possibility of danger", appeared to be qualified by the decision in R -v- Porter [2008] in which a child sustained fatal injuries in a fall down steps at school. Prosecution was commenced against the headmaster of the school and Moses LJ, in acquitting the headmaster on appeal said:

"What is important is that the risk which the prosecution must prove should be real as opposed to a fanciful or hypothetical... There is no alleviate those risks which are merely fanciful."

In the absence in that case of a "real risk", it followed that no question of reasonable practicability of measures to avoid the risk, arose and the defence was successful.

  • Moving forward a year the next landmark decision is the House of Lords' decision in R -v- Chargot Limited [2009]. This prosecution arose from an accident that occurred during the construction of a car park. A dumper truck tipped over and the driver received fatal injuries. There were no witnesses and there were no defects to the truck. Exactly what happened could not be determined. Charges which alleged a breach of sections 2 and 3 were defended on the basis the prosecution had failed to prove what act or omission had been a breach of duty. In other words what risk the Defendants should have taken further steps to protect against. That argument was rejected though and Lord Hope said:

"...when the legislation refers to risks... It is not its purpose to impose burdens on employers that are wholly unreasonable... The law does not aim to create an environment that is entirely risk free. It concerns itself with risks that are material. That, in effect, is what the word "risk" which the statute uses means. It is directed at situations where there is a material risk to health and safety, which any reasonable person would appreciate and take steps to guard against."

Notwithstanding those comments, the Defendant was found guilty because the fact there had been a serious accident was found to be sufficient to demonstrate that the risks that existed were real in that case - in other words the risk was more than hypothetical.

Given that there was also an accident in R v Porter it is difficult to distinguish the rationale for these two apparently conflicting decisions.

Nevertheless, heading into 2012 it looked as if, for a prosecution to succeed, there needed to be a real/material risk which could be evidenced by harm having been caused to someone.

  • And so we come to the Court of Appeal judgment in R -v- Willmott Dixon Construction Limited [2012]. The Defendant in that case undertook refurbishment works in which asbestos dust was released with inadequate protections in place. It was clear the dust had been released, and that further reasonably practicable steps could have been taken (adequate airlocks and respiratory equipment for example) but it was argued by the Defendant that what had happened had to have created some risk of actual danger for there to be liability. The expert evidence acknowledged that the risk from the asbestos in this case was "negligible" ..."Very broadly, one could say that one in a million per annum is about the risk of a man being struck by lightening. And we're looking at far lower risks than that in association with the ... exposures...I think that you would get in the course of a week staying in the hospital about the same exposure."

You would be forgiven for thinking, as Willmott Dixon argued, that such a low level of risk was "hypothetical", and might not be deemed sufficiently "material" for the purpose of a section 2 or 3 conviction.

The trial judge in directing the jury though, said, "In this context risk means the possibility of danger from the inhalation ... breathing in - of asbestos fibres. It is unnecessary for the HSE to prove any actual danger, but the risk must be real or material as opposed to fanciful or hypothetical." The jury convicted and Willmott Dixon appealed.

The Court of Appeal affirmed the conviction on the basis there is no threshold of danger in relation to asbestos - it is well known that inhalation of a single fibre may be sufficient to lead to mesothelioma in time. Mr Justice Hedley made clear that as in the Science Museum case, the legislation had to be interpreted in its correct social policy context:

"The purpose of the legislation is to protect those who otherwise cannot protect themselves. It does not impose absolute liability but it does impose strict obligations in terms of justifying the steps that are taken. Accordingly, the social policy imperative may give rise to criminal liability in circumstances which, absent that context, might appear surprising. Secondly...these were significant works of a potentially hazardous nature... accompanied by failures... in a context where there was no known threshold of danger."

So what conclusions can be drawn from these cases?

There seems to be a distinction being drawn by the Court between random risks which the public can't avoid unless protective steps are taken, and contained risks. Random risks seem to include airborne contaminants where anyone in the vicinity may be affected. Conversely, contained risks are those which might put an operative at risk or a limited number of the workforce.

Where risks are "random" public policy seems to dictate that even where the risk created is remote, this is sufficient for the prosecutor to overcome its probative hurdles with its case. However, if the risk is a contained one, then public policy does not seem to operate to influence the outcome to the same extent and in those cases it may still help when considering whether or not to defend prosecution, to look at whether the risk was material or hypothetical.

The practical conclusion to be drawn from the case law as it presently stands is this:

  • Where work may put the general public at risk (particularly because of airborne contaminants such as legionella or asbestos dust) any avoidable risk is unacceptable - so if reasonably practicable steps could have been but aren't taken to prevent exposure, whether or not harm is actually caused, then liability is likely to be established under section 2 and/or 3. Don't forget, though, that the fact that exposure to the risk is unlikely to have actually caused harm should help significantly with mitigation, so it is still important to be able to present evidence to that effect to the court
  • Where those at risk are a narrower, controlled number of people, then consideration needs to be given to whether the risk may be seen as hypothetical or fanciful. If no accident/injury has been sustained then as a Defendant you may have a defence. If an accident has actually occurred that may be enough to persuade the court that the risk that existed was material, unless the circumstances have remained in place for a long period without any previous incident. In those limited circumstances you may be able to persuade the court to acquit on the basis the risk was fanciful and hypothetical

The cases to defend are likely to be few and far between. It remains a difficult and uncertain battle to contest liability under the wide ambit of sections 2 and 3.