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Image: Getty Images; additional design by Tina Tiller
Image: Getty Images; additional design by Tina Tiller

BusinessFebruary 2, 2022

Your employer’s legal duty to keep you safe from omicron at work, explained

Image: Getty Images; additional design by Tina Tiller
Image: Getty Images; additional design by Tina Tiller

The onus is on businesses to protect their employees from the spread of omicron at work – and that means much more than vaccine mandates, writes employment lawyer Duncan Allan.

Two years into the pandemic, Covid-19 still brings unprecedented problems of how to minimise and prevent its spread.

The development of effective vaccines has been the biggest measure. The evidence is clear that vaccines help to significantly minimise the chances of contracting Covid-19 and, if a vaccinated person does become infected, lessen the chances of hospitalisation and death.

However, vaccines are just one tool that must be used alongside others to effectively mitigate the virus’s impact. This could not be clearer than with the current outbreak of the omicron variant worldwide. Queensland provides a good example of what could be in store for New Zealand. Up until December 2021, Queensland had been largely successful at keeping Covid-19 at bay. This was despite neighbouring states failing to prevent outbreaks. As at December 20, 2021, Queensland had recorded a total of 2,356 cases of Covid-19 since the start of the pandemic. At February 1, a little over five weeks later, this number stands at 413,670 cases.

People queue for Covid tests on the Gold Coast last month (Photo: Chris Hyde)

The major issue with the omicron variant is its high transmissibility. The vaccine reduces, but does not prevent, spread of the virus. Mitigation requires a combination of control measures in addition to the vaccine, such as mask wearing, physical distancing and adequate ventilation. 

The government has focused its attention on the push for vaccinations and with good reason: vaccinations are the most effective combatant against Covid-19. But with omicron on our doorstep we run the risk of being another Queensland, or worse, if we don’t seriously step up our efforts in other areas of prevention.

With all the focus on vaccination, employers appear to have treated it as a silver bullet. After undertaking health and safety risk assessments, many major employers including The Warehouse, Foodstuffs and Fletcher Building have implemented vaccine requirements for all, or most, of their workers. But what other health and safety requirements were implemented as part of those risk assessments? For example, instead of upgrading its ventilation systems, a certain multi-million-dollar company used poor ventilation as one of the justifications for introducing a vaccine requirement. Businesses should not use vaccine requirements to try to avoid the costs of additional effective containment measures. Health and safety requirements place greater obligations on businesses to do more.

Health and safety requirements place greater obligations on businesses to do more to protect their employees (Image: Tina Tiller)

An employer’s legal obligations

Under the act employers have an obligation to eliminate or minimise risks to health and safety so far as is reasonably practicable. This includes maintaining a safe working environment and systems of work. Worksafe guidance notes that the work environment includes ventilation and airborne particles.

Identifying and adopting one control measure, such as vaccinations, is not enough. The Health and Safety at Work (General Risk and Workplace Management) Regulations 2016 put an obligation on the business to identify the hazard (in this case Covid-19) and create a hierarchy of control measures. Under this hierarchy, businesses should first look to measures that protect multiple workers at once, such as fit-for-purpose ventilation. If that cannot eliminate the hazard then one of the control measures outlined in the regulations is the provision and use of suitable personal protective equipment. It is the business, not the worker, who has the responsibility of supplying this equipment.

An adequate health and safety risk assessment for Covid-19 should include all control measures that will minimise risk. These include vaccination, fit-for-purpose ventilation, the provision of masks and proper physical distancing. This may require many businesses to incur costs in upgrading their ventilation and providing masks, but this is the cost of complying with the law, which is in place to protect the health and safety of workers.


Ventilation plays a key role in mitigating the risk of transmission, but many workplaces, particularly old buildings, were never designed with this in mind. Some workplaces can have ventilation systems installed. This will come down to building design and cost as to whether it could be considered a requirement. Cost is a factor in health and safety assessments and is discussed further below. For now, it is enough to say that a multi-million-dollar company has a greater onus to upgrade or install built-in ventilation than a small struggling business.

Where it isn’t reasonably practicable to install a ventilation system, increased ventilation can be achieved with the use of portable High Efficiency Particulate Air cleaners (HEPA cleaners). These offer a cheaper, but still effective, way to mitigate transmission.

A study from July 2021 showed HEPA cleaners were effective at reducing exposure to aerosol particles by up to 65%. When combined with universal masking, the reduction was up to 90%. Two similar reports found that HEPA cleaners in classrooms could reduce overall aerosol particle concentrations by 80% within 30 minutes.

HEPA cleaners are most effective when close to the source of transmission, therefore multiple HEPA cleaners will be required for most workplaces, depending on the workplace size. However, there is no doubt that HEPA cleaners, particularly when used in combination with masking, will reduce the chances of transmission of Covid-19 within the workplace.

According to a study, when combined with universal masking, HEPA cleaners reduce exposure to aerosol particles by up to 90% (Photo: Getty Images)

Provision of masks 

Under the traffic light system, many businesses are required to ensure workers and people entering the premises are wearing masks. But there has been little discussion in New Zealand on what constitutes an effective mask, or even what a “mask” is. In writing various Covid-19-related legislation, the drafters have chosen not to define it any further than a “face covering”, which “means a covering of any type that covers the nose and mouth of a person”. General guidance has suggested that reusable cloth masks or disposable surgical masks are adequate. However, it has always been clear that the most effective masks are respirator masks such as N95, FFP3, FFP2, KF94 and P2 (these standards relate to the region of certification but are all equivalent. KN95 masks are also equivalent but have not been included because of the high prevalence of counterfeit masks). These masks are effective because they can filter smaller droplets. For example, a standard surgical mask can filter down to 3 micrometre solid particles whereas the FFP2 filters down to 0.075 micrometre solid particles (in other words, they are a lot more effective). Some European countries have recently made it mandatory to wear these masks on public transport and in shops. The government has recently made noises about a move to more effective masking, but unfortunately still considers standard disposable surgical masks to be adequate.

Evidence is clear that wearing the most effective masks greatly reduces the chance of transmission of the virus. A study published shortly before the omicron variant became predominant shows the effectiveness of different types of masks in close interactions with a carrier of the virus. After 20 minutes the risk of infection between two people wearing surgical masks was 10.4%. This dropped to 0.14% if both wearers had FFP2 masks. After one hour, the risk of infection wearing surgical masks was 30% but only rose to 0.4% if both people wore FFP2 masks.

With the omicron variant being far more infectious than previous variants, effective mask wearing is a critical tool in combatting spread. Additionally, some recent modelling has suggested that in scenarios where everyone is properly masked, there may be less risk of infection from omicron than from delta. This is because it appears that omicron is more prevalent in the upper respiratory tract than the lower respiratory tract and masks are extremely efficient at removing large particles produced in the upper respiratory tract. However, in every other scenario (ie where not everyone is masked), there is a much higher risk of infection from omicron. 

This shows the importance of wearing the best possible masks in order to effectively mitigate the risks of infection of Covid-19 between workers and anyone else they come into contact with during the course of their work.

Mitigating risk

The requirement on employers is not just to minimise risks, but to minimise risks so far as is reasonably practicable. The definition of what is reasonably practicable includes the following factors:

a) the likelihood of the hazard or the risk concerned occurring; and

b) the degree of harm that might result from the hazard or risk; and

c) what the person concerned knows, or ought reasonably to know, about—

(i) the hazard or risk; and

(ii) ways of eliminating or minimising the risk; and

d) the availability and suitability of ways to eliminate or minimise the risk; and

e) after assessing the extent of the risk and the available ways of eliminating or minimising the risk, the cost associated with available ways of eliminating or minimising the risk, including whether the cost is grossly disproportionate to the risk.

Overseas evidence seems clear that we can expect a large surge in cases from omicron, therefore the likelihood of the hazard occurring is high. While the chances of hospitalisations and death are lower amongst a largely vaccinated population, there is a high degree of harm that can occur. We are well aware of ways of minimising the risk of Covid-19 and use of the most effective masks and ventilation are two of the most suitable methods. Finally, while there are additional costs associated with providing N95 or equivalent masks and HEPA cleaners, this is certainly not grossly disproportionate to the risk of infection within the workplace.

Evidence is clear that respirator masks like this FFP2 are most effective at preventing transmission (Photo: Fabian Strauch/Picture Alliance via Getty Images)

In addition to these elements, the government has introduced an assessment tool to assist businesses with making an assessment of whether to introduce mandatory vaccinations at the workplace. The assessment tool says that if the answer is yes to at least three out of four of the following factors, then it is reasonable for a business to require vaccination:

  1. If a worker carries out work in an internal area less than 100 square metres.
  2. If a worker carries out work where being able to maintain one-metre distancing from other people is unreasonable.
  3. If a worker carries out work for more than 15 minutes at a distance of less than one metre from someone else.
  4. If a worker provides a service to other people who are vulnerable to Covid-19.

While this assessment tool has been developed specifically for vaccinations, it is likely that the same assessment would be relevant for other measures to mitigate Covid-19, such as mask wearing and adequate ventilation. If a risk assessment shows that mask wearing and ventilation are required (or already required by law), a proper health and safety assessment should also recommend that the most effective masks be supplied as personal protective equipment and effective ventilation such as HEPA cleaners are used if a business wants to meet its legal health and safety obligations. The purpose of the act is clear that “regard must be had to the principle that workers and other persons should be given the highest level of protection against harm to their health, safety, and welfare from hazards and risks arising from work or from specified types of plant as is reasonably practicable”. Here, the highest level of protection comes from N95 or equivalent masks used in combination with HEPA cleaners (or better).

While not every situation will be the same, in a situation where one type of mask is superior and is proven to significantly reduce the risk of the spread of Covid-19, a business will likely have a legal obligation to provide that mask. In a situation where a workplace does not contain a fit-for-purpose ventilation system, HEPA cleaners are likely required. Because the evidence is clear that masks and HEPA cleaners are more effective when used in combination, the provision of both is likely required. There is a high probability that anything less will be a breach of the Health and Safety at Work Act 2015.

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