Animal testing

Current legislation dictates that animal test data is still required to help assess potential health hazards of chemicals to humans.  Although there are valid arguments either way concerning the extrapolation of animal data to humans and whether alternative methods of assessment are acceptable, the fact remains that animals are unfortunately required in many cases for regulatory assessment.


Progress has been made in recent years to reduce the numbers of animals required during testing and in vitro test data is now more widely accepted in many cases.  There is also progress in computer modelling and recognition in the importance of reading across data within groups of chemicals.  Under the 'old' European system, the Dangerous Preparations Directive makes it clear that mixtures should be classified by calculation and not by performing animal tests on mixtures. The European REACH and CLP Regulations take this further and require approval to be obtained from ECHA, the European Chemicals Agency, before any animal tests are carried out, for both substances and preparations. Approval for new testing on animals will only be granted once all other methods to generate the necessary data have been exhausted.


Denehurst supports the development of alternatives to animal testing and has over the years successfully made the case to use old non-regulatory data, read-across methods, modelling assessment or to use protocols that require fewer animals.  Legally, animal testing must only be performed when all other options have been explored and even then, the study design must take into account animal welfare.  Denehurst will not support animal testing and does not commission animal test work.

The concerns of Denehurst reflect current legislation in Europe and contrary to the views of many who protest against animal testing, there are very strict rules on the use of animals in scientific procedures.


·         A permit (licence) must be obtained from an Government Agency (eg UK Home Office) before animal testing can be performed.  Premises will be inspected without prior warning and personnel must be suitably qualified.  The named licence holder is legally responsible and can be subject to criminal proceedings if the conditions of the licence are not met.  

·         Tests that deliberately lead to death as an end point are not permitted.  The LD50 test has been banned in Europe for many years and alternative non-lethal end points are used for classification where animal testing has to be performed.

·         Maximum permitted dose levels reflect those of classification end points; for example, acute oral testing is limited to 2000 mg/kg, longer-term toxicity testing to 1000 mg/kg/day and fish toxicity to 100 mg/l.

·         Mixtures calculated to be hazardous though CLP methods cannot be tested on animals. In-vitro testing can be performed to aid with classification decisions.

·         Repeating previous animal work is not permitted and test laboratories must demonstrate that reasonable efforts have been made in finding out if previous testing has been performed.  For new substances, an Inquiry to ECHA must be made to ensure that the substance has not been previously notified.

·     Skin and eye irritation studies are not permitted on animals if in vitro testing indicates that classification is required.  Animal tests for skin and eye irritation are not needed and waivers 'not scientifically justified' used.

·         Fish are vertebrates and are covered by animal test regulations

·      Cosmetics or chemicals to be used only in cosmetic or other personal care products cannot be tested on animals.


It should be remembered that animal testing is very expensive and even if there was no legislation restricting this work and even if chemical suppliers had no concerns about animal welfare, it does not make economic sense to perform unnecessary studies.


The UK has probably the most carefully controlled legal system for animal welfare in the World and goes beyond minimum requirements set out by EU legislation.  UK laboratories have consistently led the way in animal welfare, environmental enrichment for animals, and in finding alternatives to the use of animals in scientific procedures. 


In the US, for example, higher dose levels can be used and LD50 testing is still permitted.  In many cases, it is also expected that mixtures and preparations are tested instead of calculating effects.  


For further free advice on avoiding unecessary animal tests, contact


Denehurst Chemical Safety Ltd

Guidance from ECHA makes it very clear that new laboratory testing on animals must only be considered when alternatives are not available


Alternatives include :



If deciding not to perform new testing, justification is needed in IUCLID when completing registration documents.  The main reason for a waiver will be 'not scientifically justified', but exposure waivers can also be used.


As an example, is there any scientific justification in performing skin and eye irritation studies on rabbits when in-vitro studies can be used and where advice is given to wear coveralls, gloves and eye protection ? 


More information on Waivers  

Denehurst supports alternatives to animal testing