Dangers of Chlorine-based Bleach for Cleaning & Disinfection

Dangers of Chlorine-based Bleach for Cleaning & Disinfection

Recent work with a number of different (and unconnected) clients has revealed problems caused by a similar source – Bleach, Sodium Hypochlorite to be more exact. In one example, bleach was used to disinfect a large tank of water, initially through super chlorination (usually twice the dose quickly) and then to maintain clean water. In another example, which is more worrying, is the use of bleach for routine janitorial cleaning. These are just a couple of many examples we’ve seen, particularly in cleaning applications which is also a recurring theme amongst smaller cleaning operations.

Chlorine (in the form of a Hypochlorite ion) is a widely used disinfectant in the water industry and is highly effective against a wide range of bacteria and viruses. So, it didn’t come as any great surprise to see this form of disinfection. What was a surprise was the complete lack of awareness about the risks of using and handling Hypochlorite-based products, and this ever more so applicable to the use of bleach for cleaning. Because of the lack of awareness of the risks, Hypochlorite-based products were handled without any due regard for safety to themselves, their nearest neighbors and the surfaces the product is applied to.

Health and Safety

Depending where in the world different legislative bodies regulate the use and handling of chemicals in the workplace, usually requiring a minimum standard of protection for the skin and the face. In the UK and the US, the Health and Safety Executive and the Occupational Safety and Health Administration respectively, regulates the safety of the workplace and mandates the wearing of personal protective equipment (PPE. E.g. face protection and suitable gloves); they also require a safe working environment through adequate ventilation and emergency measures in place should an accident happen. Little did those involved in the examples above knew that all these safety measures are for the use and handling of bleach in the workplace.

Bleach causes severe and acute burns

Bleach is a powerful oxidizing agent and as such is corrosive to substances and surfaces. Just like sodium Hydroxide, bleach causes severe burns to skin, eyes, and in a vapour form, will cause severe and acute burns to the lungs and mucous membranes. One of the major health hazards is the liberation of toxic Chlorine gas when bleach is mixed with other cleaning products, acids and ammonia products being the principle causes. As a salient reminder, Chlorine gas was used as a chemical warfare agent in WW1.

When bleach is added to ammonia cleaning products, that also includes urine, highly toxic Chloramines are produced which can result in similar health problems to chlorine gas.

Generally, the mixing of bleach with other cleaning products is purely unintentional. For example, it is quite common for a toilet de-scaling product to contain acids – Acids dissolve water scale – and after descaling, bleach is introduced to the bowl without proper regard to the thorough rinsing off the acidic product. Chlorine gas is immediately released just as you are bending over the bowl.

Very severe cases of inhalation of chlorine gas can cause pulmonary edema; if ingested, acute, leading to chronic, poisoning have been noted.

Bleach damages surfaces

One of the most common areas bleach is used in the home is the kitchen, more specifically worktops and sinks. These worktops, including stainless steel skins and worktops, are highly sensitive to bleach. The chloride ion (Cl-) penetrates the protective surface film (stainless steel 316) and reacts to cause corrosion. This corrosive reaction causes microscopic cracks that, when the steel is subjected to mechanical stress, propagate leading to sudden failure. On laminated worktops, like Formica, bleach oxidises the polymers and bleaches the colouring. This slowly breaks down the material as the polymers break, making the surface more brittle and causing cracks to appear. You may have noticed that accidental splashes of bleach, if left on the surface, leave an indelible mark.

Bleach as a Disinfectant

As we have already seen Chlorine is a widely used disinfectant in the water industry and is highly effective against a wide range of bacteria and viruses. We have already seen the dangers of uncontrolled use of chlorine (in bleach), but in a controlled environment, chlorination is highly cost effective and relatively safe. The one major problem with chlorination is the presence of organic matter, chlorine reacts to produce potentially carcinogenic trihalomethanes.

From a cleaning point of view, the problems and risks of using bleach as a disinfectant completely dwarf the biocidial properties. There are many non-bleach based products on the market, one good alternative is using Quaternary ammonium compounds (Quats), benzalkonium chloride being just one such example. However, they are not quite as effective in killing viruses and bacteria, so longer contact times are needed, but they don’t have potentially dangerous reactions that bleach could cause. The market for safer disinfectants is ever evolving and new biocides are showing much better efficacy and wider kill capability.

To sum up:

  • Mix it with an acid and it makes chlorine gas – highly toxic.
  • It damages surfaces often surfaces you wouldn’t think it can, like concrete, stones and steel
  • It doesn’t clean at all since it isn’t a detergent and manufacturers can’t put it into detergent products because of the potential for making chlorine
  • It wont remove scale from a shower or a toilet – it just bleaches.
  • It damages fabrics even when used as bleach since it weakens the fabric
  • It bleaches wood so splashes cannot be removed
  • It does not remove mould stains from grout or sealant or walls, just bleaches the wall paint or paper.
  • It is horrible to smell when you do use it
  • It is not a good disinfectant at all. It takes well over 20 minutes to work and then has very mixed results
  • It kills you if you drink it
  • It causes severe burns if it’s splashed on to skin or eyes


There are many more, much better formulated detergent products which are safer in use, both on surface materials and for the operator, one would question why chlorine is specified as a cleaning product. It simply is a lack of knowledge, since most in our industry has avoided the use of hypochlorites for a good few years now.

Hydrogen Peroxide, QAC’s and Hypochlorite disinfectants have their place within the overall cleaning and hygiene system, but powerful disinfectants like these need to be managed due to their corrosive chemical nature (Hydrogen Peroxide and Hypochlorites) and to prevent the growth of resistant strains of bacteria. Hydrogen Peroxide, for example is a very effective decontaminant but can only be used in enclosed rooms, emptied of staff and patients and sealed for a few hours, as it can present serious health effects as low as 7ppm. Also Hydrogen Peroxide due to its inherent instability is non-residual; with new bacterial growths being detected within a few days after an infected patient has been introduced into the room; so the decontamination process is only a small part of an overall cleaning hygiene system.

It’s important to point out that all disinfectants are ineffective in the presence of organic matter i.e. the surface to be disinfected must be visibly cleaned first. I feel that it is important to mention further that disinfectants and sanitisers should be rotated in use, rather than relying one just one type on a regular basis. There are many more very effective disinfectant and sanitiser products, both residual and non-residual, now available, many with patents on them.  Most are safer to use than hypochlorites or peroxides and are more effective than QAC’s. Are they being considered, I wonder?

Rafael Cobos