Health & Safety Department


Guidance on sensitisers in the workplace, including laboratory animal allergens (LAAs).

What are sensitisers?

Sensitisers are substances which can cause sensitisation in the lungs (respiratory sensitisers) and/or skin (skin sensitisers) after exposure to them. Once sensitised, individuals can have sever reactions to further exposure, even in small amounts. In the most extreme cases, individuals may develop asthma and/or dermatitis respectively.

Identification of sensitisers

Many such substances are indicated by the following hazard statements;

  • H334 May cause allergy or asthma symptoms or breathing difficulties if inhaled
  •  H317 May cause an allergic skin reaction

However, many sensitising substances do not hold such a phrase, for example laboratory animal allergens.

Please note that risk phrases such as 'R42 May cause sensitisation by inhalation' are no longer in use and have been replaced by equivalent hazard statements, such as 'H334 May cause allergy or asthma symptoms or breathing difficulties if inhaled' when the CHIP Regulations were replaced by the CLP Regulations

A list of sensitisers can be found on the Health and Safety Executive website.


Respiratory - signs and symptoms of asthma include:

  • attacks of wheezing, coughing, chest tightness or shortness of breath. Associated conditions are;
  • rhinitis (sneezing/runny nose) and/or
  • conjunctivitis (itchy and inflamed red eyes)

The symptoms can develop immediately after exposure, but sometimes appear several hours after exposure, possibly at night, and so any link with workplace activities may not be obvious. More detailed information on asthma can be found on the Health and Wellbeing website - Asthma pages.

Skin - signs and symptoms:

The most common symptom is inflammation known as dermatitis or eczema. It is characterised by;

  • rubor (redness) and calor (heat) from dilation of local blood vessels,
  • tumour (swelling) and blistering from plasma leaking from the vessels to the surrounding tissue and
  • itch caused by stimulation of nerve fibres
  • Secondary changes due to infection and scratching include crusting, ulcers and thickening of the skin

External agents tend mostly to come into contact with the hands and forearms, so around 95% of work-related skin diseases occur in this area. The majority of the remainder are on the face.

Legal requirements

The COSHH Regulations require that a suitable and sufficient risk assessment of any sensitisers is undertaken before any possible exposure occurs. Further guidance on COSHH is available on our website.

Risk assessment

Template COSHH risk assessments are published by the Health and Safety Department with accompanying detailed guidance for their completion.

Individuals react differently to exposure to these substances and there are therefore no universal ‘safe’ limits of exposure. However, some substances which are classified as sensitisers may have a Workplace Exposure Limit (WEL) - exposure must be below this limit but should, in any case, always be reduced to as low as reasonably practicable.

Control of exposure

Control of exposure should follow the hierarchy of control;

  • Eliminate
  • Reduce/substitute
  • Prevent people coming into contact with hazard
  • Safe system of work
  • Personal protective equipment

If the exposure cannot be eliminated, then it should be controlled at source, for example using the sensitiser within a fume cupboard to remove the substance from the individuals breathing zone, if at all possible. PPE, including respiratory protective equipment, must only be used as a last resort.

Fume cupboards/downdraught tables

A fume cupboard is basically a fire and chemical resistant box (enclosure) with one open side at the front (face) - this is covered by a usually vertical opening window (sash) which gives the users access to the inner working surfaces. Functionally it works by drawing large volumes of air into the cupboard through the face; this is then extracted from the top of the cupboard via ductwork to the external of the building, thus airborne contaminates originating from inside the cupboard are prevented from escaping by the inward flow of air and the operator is protected from harmful exposure.

Downdraught tables work similarly to fume cupboards - they draw the contaminant away via the ducting and then expel this contaminated air safely

More in-depth guidance is available in the following Code of Practice.

CS CoP004 Local Exhaust Ventilation details the safe management of local exhaust ventilation (LEV) systems. This CoP was approved by the University Safety, Health and Wellbeing Committee at it's November 2022 meeting. A Guidance note accompanies this CoP which covers the general safety guidance, installation and design, safe use, environmental considerations and recirculatory fume cupboards.

In addition, a short Guide for Schools and Departments has been produced to assist Schools/Departments in implementing the new CS CoP004.

Appendix 2 - example log book in WORD format for local amending.

Appendix 3 - contractor induction in WORD format for local amending.

Personal protective equipment

Personal protective equipment, other than mandatory eye protection, is always to be regarded as the last line of defence, and should only be required when the hazard cannot be controlled at source. It is important to note that PPE only protects the wearer; therefore whilst the wearer is protected colleagues working nearby could well be affected by the hazards of the work.

More in-depth guidance is available on the PPE guidance pages.


Latex allergy is a well-known and increasing problem in healthcare and laboratory workers. In many cases the choice of latex gloves is made purely on economic grounds with little reference made to the potential for allergic reaction and sensitisation, or indeed the suitability of latex as an effective barrier against a particular hazard. Workers at increased risk at developing latex allergy are those with ongoing and repeated exposure to latex, individuals who are atopic and those with spina bifida.

More in-depth guidance is available on the hand protection guidance pages.

Respiratory protective equipment

If your risk assessment shows that respiratory sensitisers (including animal allergens) are not controlled sufficiently by other means (for example local exhaust ventilation) then RPE will need to be worn at appropriate times.

The instances where there is need for the wearing of RPE should be few as respiratory protection should only be considered necessary when engineering control cannot be used effectively. Thus, work involving toxic gases, hazardous volatile substances and dusts should be kept away from persons by placing such work in a glove box, fume cupboard or other well ventilated zone.

RPE guidance when working with animals

Animal Allergens Guidance Document

Mandatory facefit testing

All staff who, after a risk assessment has been completed, are required to wear a tight fitting face mask, must undertake a facefit test before commencing work. An individual test takes approximately 30 minutes - this involves an element of respirator fit training, which also meets a legislative requirement.

Full details on the procedure and how to request a test are available via the link below.

Health Surveillance

Respiratory health surveillance

Under COSHH Regulation 11, if a risk assessment shows that a respiratory sensitiser (e.g. animal allergens) is not contained and/or controlled sufficiently by engineering measures, or there is reliance on RPE for control, it is likely that respiratory health surveillance will be required. Health surveillance consists of periodic health checks and/or health monitoring, and is provided by the University's Occupational Health Service. Further information on the University's system can be found at:

Skin health surveillance

Similarly, health surveillance may be required for work with a skin sensitiser.

Organising health surveillance

If the outcome of the risk assessment shows health surveillance is required, the relevant line manager must ensure the individual(s) concerned are presented for baseline and subsequent appointments. This can be arranged via the local health surveillance contact person in your area (usually your local safety adviser/manager) or direct with the OHS.

Occupational Health Service

  • Health and Safety Department
  • The University of Edinburgh

Contact details



Drummond Street Annexe
Drummond Street

Post Code


All staff must be trained to ensure they understand their risk of exposure and how to ensure this exposure is controlled.

Mandatory training – laboratory animal allergens

On 20th August 2014, the Central Management Group (CMG) gave its full backing to the creation and delivery of 3 mandatory training courses for all Research Group Leaders, Principal Investigators and other relevant managers and supervisors who themselves are potentially exposed to animal allergens, and/or whose group members, or other relevant colleagues, would expect to have a similar potential for exposure, and all their staff/researchers in their groups. 

Health and Safety Awareness for Principal Investigators or Supervisors

All Principal Investigators or supervisors who work with laboratory animals (see above) must complete this training. It is recommended for all other Principal Investigators or supervisors.

Please contact your School Safety Adviser to ascertain if face to face sessions are offered or if you should use the e-learning package.

Health and Safety Awareness for Principal Investigators and Supervisors online course 

Laboratory animal allergens and health surveillance

If staff or students will be undertaking work with animals, then the PI or supervisor, as well as those staff or students working with animals, must also complete the laboratory animal allergens and health surveillance e-learning course in LEARN.

Please contact your School Safety Adviser to ascertain if face to face sessions are offered or if you should use the e-learning package.

Respiratory Protective Equipment

If staff or students are required to wear any respiratory protective equipment, then the PI or supervisor, as well as those staff or students working with animals, must also complete the respiratory protective equipment e-learning course in LEARN.

Please contact your School Safety Adviser to ascertain if face to face sessions are offered or if you should use the e-learning package.

Please contact the Training and Audit Unit for further guidance on suitable training.

Training and Audit Unit

Contact details

COSHH Health record

All staff who may be exposed to sensitisers should have a COSHH health record. The Unierity has developed the COSHH Health Passport System (secured) (CHPS) for this purpose. Please contact us for more information if you wish to start using CHPS.

Occupational Hygiene Unit

Contact details