Deep Cleaning Steps to take after COVID exposure in the workplace

The pandemic radically brought attention to how important it is to clean your workplace regularly. 

Sloppy cleaning regimens are now no longer an aesthetic problem, they literally determine the chances of serious illness (or even potentially death) that workers will face.

While workplaces continue to open up as we exit lockdown, it is clear by now that COVID will not be going away any time soon. Employers will need to get to grips with tackling COVID head on if they wish to survive the coming months and years.

The coronavirus can be spread through particles in the air, and can live on surfaces for up to 72 hours. This complicates deep cleaning attempts, however as this article goes into, there are techniques which can be used to tackle both airborne and surface bound particles.

While it is in some cases possible to quarantine whole premises for 72+ hours, in many cases this is either impossible or at least highly undesirable.

For large organisations such as schools, the chances of at least one person testing positive is significantly raised – should organisations of this size shut for 3 days every time there’s a case, they would possibly be permanently shut.


If recent COVID exposure has occurred in the workplace, then those tasked with cleaning must wear appropriate personal protection equipment (PPE) to limit their risk of personal contact.

If the contaminant is either likely to be pervasive, such as in a room where an infected person has slept, or in high quantities, such as significant bodily fluid spills, then additional cleaner protection will be necessary.

In addition to an apron and gloves, eye, nose, and mouth protection will be necessary. If in doubt, check with Public Health England – their teams are able to provide localised advice for individual situations. 

The safest way to deal with PPE after use in a potentially infected environment is to dispose of it. Utilise single use PPE, and when done with cleaning, be sure to double bag it, then quarantine the bags for 72 hours.

Once the quarantine period has been completed, it can be disposed of in normal rubbish bins – it doesn’t have to be a bio-specific site.

Although PPE is designed to minimise the risk of contact with infectious substances, it isn’t 100% effective. Once done with cleaning, and after the PPE has been removed and disposed of, cleaners must wash their hands with soap and water for at least 20 seconds.

This is important for everyone, but especially so in this case, as when removing PPE it is very possible that you will come into contact with the virus.

Where to clean

The infected individual is unlikely to have been in contact with every part of the premises, meaning they are unlikely to have spread the contamination everywhere.

However, it is potentially dangerous to just clean areas you think the individual has gone; it is unlikely that you can retroactively track their movements with complete accuracy, and even if you could, as the virus can be spread through invisible respiratory droplets, they could have contaminated spaces they had no direct contact with.

Unless the premises in question is truly vast, like a warehouse or multi-story office building, it is advisable to clean the whole thing.

That being said, there are places which should receive special attention: all surfaces which the individual came into direct contact with need wiping down thoroughly with disinfectants.

These include doors and door knobs, handrails, office spaces, toilets, and any other places they spent significant periods of time in.

Areas through which they passed rapidly, such as corridors and entrances, are at less risk of having high concentration of viral contaminants, but need cleaning nonetheless. 


The most specific and accurate way of disinfecting surfaces is through direct contact – in other words, wiping them.

This should be done with disposable cloths and mop heads; if they were to be reused, there is a risk of spreading the infectious material elsewhere.

Always check that the disinfectant being used is effective at killing the virus; the World Health Organisation advises the use of either alcohol based disinfectants with an ethanol content of over 70%, or one with 0.05% sodium hypochlorite (NaCIO.)

Like PPE, used cloths which are known to have come into contact with contaminants must be double bagged, quarantined, and disposed of. It can be tempting to wash them, but every time contaminated materials are handled and transported, it raises the risk of infection and continued contamination, no matter how careful you are.


Fogging can be an essential component of deep cleaning.

While wiping surfaces is an appropriate way of targeting specific areas, such as door handles and desks, it is impossible or at least highly impractical to wipe every surface in a building. Some areas are simply hard to reach, such as in small gaps and on high up places, and in large spaces, it would take days to do every surface.

In these situations, fogging may be appropriate as an additional method.

Fogging is a cleaning method in which a disinfectant, such as hydrogen peroxide, is suspended in the air in a mist.

This mist can then get into the small areas and surfaces which the wiping down stage missed. As the Coronavirus is also transmittable through the air, the mist can also kill the air-born droplets; this can be essential for badly ventilated spaces, which may otherwise need quarantining for longer.

Fogging is not new, having been used to combat infections such as MRSA for a long time, but it has recently become popularised in the fight against Covid, and for good reason. It’s proven to kill 99% of viruses, and can rapidly disinfect large spaces which would take conventional cleaning methods hours or days to do.

Think of getting expert help

Deep cleaning in virally contaminated areas is a complex and potentially dangerous process. Some methods, such as fogging, are best carried out by experts – they can be dangerous in and of themselves, and require both expert knowledge and specialist machinery.

Our team at SMC Premier, who have over 35 years experience in the area, can assist with practical advice and help on how to strategise your response to Coronavirus exposure in the workplace. You can also discover our office cleaning services via our dedicated page.