Introduction to Health and Safety at Work

Paper 2 – Question 3
For EACH of the following agents, 
outline
the principal 
health effects 
AND identify
a typical workplace situation 
in which a person might be exposed:
(i) carbon monoxide 
(2)
(ii) 
asbestos 
(2)
(iii) 
legionella 
bacteria 
(2)
(iv) 
hepatitis 
virus. 
(2)
Answer:
(i) Carbon monoxide is a colourless, tasteless and 
odourless gas. It causes headaches and breathless-
ness and at higher concentrations unconsciousness 
and death. The most common occurrence of carbon 
monoxide is in exhaust gas from a vehicle engine. 

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Specimen answers to NEBOSH examinations
431
Working in a vehicle repair garage without proper 
ventilation to exhaust gases would expose a person 
to carbon monoxide fumes.
(ii) Asbestos produces fi ne fi bres which can become 
lodged in the lungs. This can lead to asbestosis 
(scaring of the lungs), lung cancer or mesothelioma –
cancer of the lining of the lung. Asbestos can be 
found in buildings, in ceiling tiles and as lagging 
around heating pipes. When these sites are dis-
turbed, the asbestos fi bres become airborne and 
inhalable affecting those engaged in maintenance or 
demolition work.
(iii) Legionella is an airborne bacterium and is found in 
a variety of warm water sources between 20 and 
45ºC. It produces a form of pneumonia caused by 
the bacteria penetrating the alveoli in the lungs.
The disease is known as Legionnaires’ disease
and has symptoms similar to infl uenza. The three 
most common systems at risk from the bacteria are 
water systems that incorporate a cooling tower, air 
conditioning units, and showers. People working 
on these systems or working in the area of infected 
systems are at risk, particularly if they are over
45 years of age and it affects men more than 
women.
(iv) Hepatitis is a disease of the liver and can cause
high temperatures, nausea, jaundice and liver 
failure. The virus can be transmitted from infected 
faeces (Hepatitis A) or by infected blood (Hepatitis 
B and C). Hospital workers and fi rst aiders who 
come into contact with blood products are at risk of 
hepatitis.