A hazardous substance is a material or substance with one or more hazardous properties that can cause harm to a person either directly or indirectly.
For example, you may work directly with hazardous substances when preparing and administering specific drugs/medicines, during the cleaning and disinfecting of surfaces and equipment, and during disposal. You may also be exposed indirectly during processes that create or release a hazardous substance e.g. surgical smoke, or when caring for patients who are being treated with certain drugs that may be present in their bodily fluids.
It is easy to think of a hazardous substance as something which comes in a bottle or container and has warning signs on the label. However, that is not always the case and hazardous substances are present in a variety of forms including:
- liquids
- dust
- vapour
- fumes
- mists
- gas
- biological agents (e.g. bacteria, viruses, parasites).
Hazardous substances may enter the body in several different ways and the form of the hazardous substances influences this. It is also possible for a substance to enter the body in more than one way.
- acute - an immediate reaction which may occur after one exposure or multiple exposures (e.g. skin irritation), or
- chronic - meaning it may take months or years to appear and is a result of repeated small exposures (e.g. exposure to hazardous medicinal products like chemotherapy drugs or anaesthetic gases; see below for more information).
In health and social care, some of the hazardous substance you may be exposed to in the workplace include:
- biological agents from exposure to blood, bodily fluids and airborne viruses (e.g. COVID-19, RSV, flu and fungi such as aspergillus (black mould)
- surgical smoke from electrocautery, lasers and ultrasonic devices, which may contain chemicals and biological agents
- hazardous medicinal products (e.g. medicines such as cytotoxic drugs)
- anaesthetic gases (e.g. nitrous oxide (Entonox))
- chemicals like chlorine-based cleaning products.
Hazardous substances can enter the body by:
- inhalation
- ingestion
- injection (for example, sharps or needlestick injuries)
- absorption through the skin or eyes.
Employers are required to implement control measures to protect you from exposure to hazardous substances. There should be a series of controls implemented and the risk assessment process will consider:
- eliminating the substance (e.g. changing the process or activity)
- using a less harmful substance or a different form of the substance
- altering working procedures or processes
- engineering controls, such as totally or partially enclosed systems or local exhaust ventilation
- where risk remains after other control measures have been implemented, the use of personal protective equipment (PPE)
- providing information on the risk assessment and safe system of work to you
- monitoring controls to ensure they are effective - which may include air samples or surface wipe testing and/or health surveillance.
Risk assessments must be recorded in writing where there are five or more employees. It is a good practice to do so anyway.
A hazardous medicinal product (HMP) is any pharmaceutical substance that can cause specific health effects and harm to nursing staff if they are exposed to them. Currently the UK doesn’t have an accepted definition, but in the European Union an HMP is defined as something which is reprotoxic, carcinogenic or mutagenic.
HMPs include cytotoxic and cytosatic drugs used in cancer treatment, immunosuppressants for autoimmune conditions like rheumatoid arthritis, lupus and HIV, and organ transplantation medicines. Some hormonal therapies for the treatment of breast or prostate cancer, certain antivirals and antibiotics are also HMPs.
Detailed risk assessments must be carried out of any areas, tasks and activities where HMPs are stored, prepared, handled, administered and disposed of.
Risk assessments should outline controls to prevent or - where this is not possible - to minimise the risk of exposure for staff to a level as low as is reasonably practicable. This includes additional requirements such as:
- to use totally enclosed systems e.g. closed system transfer devices
- the prohibition of eating and drinking in areas at risk of contamination
- regular cleaning of floors, walls and surfaces
- the use of warning signs, and
- safe storage, handling and disposal,
Employers are required to do this under the Control of Substances Hazardous to Health regulations (COSHH) (see below).
Your employer should train you to identify HMPs, understand the health risks, recognise warning symbols, give you information on controls and safe operating procedures to minimise exposure risks, the importance of personal hygiene and handwashing, what to do in case of emergency e.g. spills and leakage and correct disposal techniques.
If you’re concerned
Speak to your RCN health and safety rep or contact our advice team if you’re concerned about exposure to HMPs in your workplace.
Further reading
Hazardous medicinal products: what nursing staff need to know | RCN Magazine
RCN position statement: The use of Hazardous Medicinal Products
The Control of Substances Hazardous to Health 2002 Regulations (COSHH) and the Control of Substances Regulations (Northern Ireland) 2003 place a legal duty on employers to ensure exposure/potential exposure to hazardous substances in the workplace is prevented - or where this is not possible - adequately controlled.
Employers should evaluate the risk from hazardous substances by the undertaking of a COSHH risk assessment, including:
- how, when and where the substance is used
- who is likely to be exposed
- the potential to cause harm
- the frequency of exposure, and
- the level of exposure.
The assessment should also include activities such as maintenance and cleaning, as well as emergency situations.
The risk assessment should be carried out before the commencement of any work involving hazardous substances and in consultation with staff and/or their representatives, such a trade union representative.
The risk assessment should take into account substances which are:
- brought into the workplace* and handled, stored and used (e.g. disinfectants)
- produced or emitted (e.g. as gas, fumes, vapour dust etc) by a process or an activity, or as a result of an accident or incident
- used for, or arising from, maintenance, cleaning and repair work
- produced at the end of any process (e.g. wastes, residues, scrap etc)
- produced from activities carried out by another employer’s employees in the workplace (e.g. contractor).
(*This should also include any hazardous substances handled, stored and used, or which employees may be exposed to outside of the employer’s site/buildings (e.g. in community settings))
Controls in the risk assessment should be regularly monitored to ensure they remain effective e.g. environmental monitoring.
Risk assessments should be reviewed after any incidents or near miss occurs, when something changes e.g. processes, guidance or at a set time frequency.
Hazardous substances that are manufactured should have product labels which help identify the hazards associated with the substance. These will be in the form of a pictogram in the shape of a diamond with a distinctive red border and white background.
A safety data sheet (SDS) provides key information which can assist the COSHH assessment process including the hazard classification, exposure controls, workplace exposure limits, handling and storage and emergency measures. SDSs can be requested from suppliers or many are available online. However, it should be noted that not all substances have a SDS.
Hazardous medicinal products that are in a finished state for the end user e.g. tablets in blister packs or creams/ gels in bottles do not require manufacturers to label them as hazardous or have safety data sheets.
You should:
- follow safety procedures issued
- use PPE required and ensure it is put on and taken off correctly
- report any incidents or unsafe conditions through the employer incident reporting system and to your health and safety representative
- attend training and health surveillance when required.
Guidance can be found on the Health and Safety Executive (HSE) website, RCN sharps safety guidance and the NHS Staff Council Guidance on the safe use of chlorine-based disinfectant chemicals in the NHS.