Introduction to Health and Safety at Work

Hierarchy of risk control
When assessing the adequacy of existing controls or 
introducing new controls, a hierarchy of risk controls 
should be considered. The Management of Health and 
Safety at Work Regulations 1999 Schedule 1 specifi es 
the general principles of prevention which are set out in 
the European Council Directive. These principles are:
1. Avoiding 
risks
2. Evaluating the risks which cannot be avoided
Likelihood
Severity
Slight 1
Serious 2
Major 3
Low 1
Low 1
Low 2
Medium 3
Medium 2
Low 2
Medium 4
High 6
High 3
Medium 3
High 6
High 9
Occupational risk level
Low
Medium
High
Organizational
risk level
Low
L
L
M
M
Medium
L
H
High
M
H
Unsatisfactory
L
Low risk
M
Medium risk
H
High risk

---

Risk assessment
73
3. Combating the risks at source
4. Adapting the work to the individual, especially as 
regards the design of the workplace, the choice of 
work equipment and the choice of working and pro-
duction methods, with a view, in particular, to allevi-
ating monotonous work and work at a predetermined 
work-rate and to reducing their effects on health
5. Adapting to technical progress
6. Replacing the dangerous by the non-dangerous or 
the less dangerous
7. Developing a coherent overall prevention policy 
which covers technology, organization of work, 
working conditions, social relationships and the 
infl uence of factors relating to the working 
environment
8. Giving collective protective measures priority over 
individual protective measures and
9. Giving appropriate instruction to employees.
These principles are not exactly a hierarchy but must be 
considered alongside the usual hierarchy of risk control 
which is as follows:
➤
elimination
➤
substitution
➤
changing work methods/patterns
➤
reduced or limited time exposure
➤
engineering controls (e.g. isolation, insulation and 
ventilation)
➤
good 
housekeeping
➤
safe systems of work
➤
training and information
➤
personal protective equipment
➤
welfare
➤
monitoring and supervision
➤
review.