Disinfectants are classified as hazardous substances. Although they are used to help ensure food hygiene, many can be harmful if ingested or inhaled in sufficient quantity.
COSHH assessment
The Control of Substances Hazardous to Health Regulations (COSHH) require employers to prevent or control exposure to hazardous substances. Where exposure cannot be prevented, employers must assess the risk to health, and provide adequate control measures when using hazardous chemicals.
The assessment should include:
- a list of all chemicals to be used
- their hazards and measures provided to control operator exposure (covering safe storage, chemical compatibility, working concentrations/safe dilution procedures and application procedures and equipment)
- any air monitoring or health surveillance requirements
- information and training requirements
- provision of washing facilities
- an emergency action plan (such as for spillage)
- waste disposal arrangements
There is more guidance on carrying out a COSHH risk assessment.
Classification and labelling
Suppliers of disinfectants have duties for classification and labelling under the Classification, Labelling and Packaging of Substances and Mixtures Regulations.
You can find HSE guidance on chemical classification, labelling and packaging (CLP).
Hazards of disinfectants
Disinfectant suppliers should provide a material safety data sheet to set out the hazardous properties of each product. This provides information on the health hazards, physical and chemical characteristics, first aid and how to use the chemical safely.
Disinfectants commonly used in the food, drink and catering industries include:
- surface active agents (surfactants) – some of these detergents have biocidal properties and are classified as skin, eye and respiratory irritants
- alcohols – these are used as skin cleaners as well as a transport medium for other active ingredients, but are irritant to eyes, nose and throat at high airborne concentrations and can be a fire risk
- aldehydes – glutaraldehyde is classified as a skin and respiratory sensitisor and formaldehyde is a strong respiratory irritant, which is also classified as a category 3 carcinogen
- peracetic acid – a powerful oxidising agent which is also extremely corrosive
- hypochlorite and organic chlorine-releasing compounds – these are corrosive in their concentrated form and are classified as eye and skin irritants when diluted
You should normally avoid disinfectants containing chemicals that are toxic by inhalation or to the skin, or are classified as sensitisers (for example some aldehydes) unless the sanitation programme identifies an absolute requirement. In such cases, strict safety measures to control exposure will be required.
Controlling exposure
Storage
Consider the potential for chemical reaction when more than a single disinfectant is used.
Incompatible chemicals should be stored separately. For example, chlorine-based disinfectants release toxic chlorine gas when in contact with acid or oxidising detergents.
Hypochlorites form irritant nitrogen halide vapours in contact with amines (such as quaternary ammonium compounds) and should be stored separately.
Disinfectants containing peracetic acid form explosive mixtures with cleaners containing acids or alkalis.
Handling concentrates and dilution procedures
Full-strength concentrates are rarely used for disinfection purposes. Working concentrations should not exceed manufacturers’ specifications as overdosing increases the risk to workers, in addition to being wasteful, and may damage plant and equipment.
Where costs allow, buying disinfectants in their dilute form or in pre-pack quantities for direct dilution are the safer options. Where these are not available or the costs are too high, diluting concentrates by auto-metering, or positive displacement using drum pumps, are considered safer than gravity feed from taps. The latter may jam or be displaced, resulting in uncontrolled leakage into the workroom.
Diluting concentrates by manually tipping drums or carboys is extremely poor practice. It will inevitably cause a spill risk and should not be carried out.
Application procedures
Clean-in-place (CIP) systems
These systems are the safer option for internal disinfection of plant and equipment. This minimises exposure to operatives so long as the plant is maintained and safe systems of work are used.
Mist and foam spraying
This generates aerosol likely to produce whole-body exposure to the disinfectants. A greater risk is presented by pressure mist spraying where higher levels of aerosol will be generated. Suitable personal protective equipment (PPE) and respiratory protective equipment (RPE) should be provided.
Suitable RPE will range in type from disposable masks, used to protect against liquid aerosols (particle filters marked SL), to airline breathing apparatus, depending on the toxic nature of the disinfectant and personal and work-related factors.
PPE may include:
- chemical suit or wetproof apron/overalls
- boots,
- gloves/gauntlets
- a visor for eye protection
For example, spraying aldehyde or peracetic acid formulations is likely to require the provision of airline breathing apparatus with full face mask or visor, in addition to full chemical protective clothing, boots and gloves or gauntlets.
Fogging
This employs similar disinfectants and concentrations to those used in mist and foam applications. However, fogging presents a particular risk to the respiratory system as it produces smaller droplets than spraying. These can remain suspended in air for 45-60 minutes or longer, depending upon the droplet size.
This method requires:
- a COSHH risk assessment for each type of agent used, and
- strict management procedures, such as air sampling, to prevent early re-entry of people into fumigated areas, particularly where the more hazardous disinfectants are used (for example aldehydes or peracetic acid)
Soak tanks and manual disinfection (bucket, mop, cloth and brush)
These methods present a risk of skin and eye exposure (including from splashes). In many cases, they will require the use of an impermeable apron, overalls, gloves/gauntlets and safety spectacles or a visor for protection.
Where volatile chemicals or respiratory irritants/sensitisers are used (for example alcohols, formaldehyde or glutaraldehyde), respiratory protection may be required, particularly when disinfecting in enclosed spaces.
Disinfectant penetration and contamination of PPE
It is important to ensure that garments, gloves and boots selected have the ability to resist penetration by the disinfectant concerned. Manufacturers and suppliers have duties to supply this information. Although some types of PPE provide very high levels of protection, breakthrough will eventually occur so none provide 100% protection.
Skin exposure may occur when removing used PPE. Suitable disposable gloves offer an easy management system to eliminate hand exposure from gloves that become contaminated inside. Advice and information for operators is necessary to ensure the PPE provides the protection needed.
Maintenance
Disinfectant application equipment should be regularly maintained. Exposure control equipment should be kept in efficient working order and good repair.
PPE and RPE should be examined and, where appropriate, tested at suitable intervals. Gloves should be inspected visually every time they are used. Disposable gloves should only be used once if chemicals are handled.
Air sampling
Initially, air sampling may be required to check re-entry is safe into areas where fogging has been carried out, particularly when high-hazard disinfectants are used, such as aldehydes.
Air sampling may be used to identify settling times or the required number of ventilation air changes to reduce airborne concentrations to safe levels prior to re-entry. However, the majority of disinfectants do not have occupational exposure limits. In these cases, you could refer to published guidance which describes settling times.
Health surveillance
Employers are required to carry out health surveillance if exposure of any employee to any disinfectant means:
- an identifiable disease or adverse health effect may be related to the exposure
- there is a reasonable likelihood that the disease or effect may occur under the particular conditions of work, and
- there are valid techniques for detecting indications of the disease or the effect
Use of aldehydes as disinfectants will require health surveillance. It is also likely to be required where there is a risk of contact dermatitis, which is associated with some disinfectants.
Information and training
Operators should be informed about the hazards of the disinfectants they work with and the risks created by exposure to these chemicals.
They should be:
- instructed in the precautions to take and how to use the control measures provided
- informed of the results of any air monitoring and health surveillance
Washing facilities
In many cases, skin is the principal organ that may be exposed to disinfectants, so ready access to washing facilities is essential.
Employers should ensure that suitable facilities are provided to allow employees to clean themselves after using disinfectants and before eating and drinking.
PPE should be cleaned after use and stored separately from everyday work wear.
Where showers or eye-sprays are provided, they should be frequently flushed through. You should also take account any potential risk from legionella bacteria, and take appropriate precautions.
Emergency procedures
Emergency procedures should be in place, particularly when handling larger quantities of concentrated disinfectant.
Emergency washing facilities (such as showers or eyewash stations) should be available including measures to irrigate eyes in the event of splashes.
Check the material safety data sheet for the appropriate method for handling spillages, which may include spill trays or absorbent granules, for example.
Consider environmental issues in the event of a spillage, particularly to prevent spillages running into storm or surface drains.