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Our facilities are designed to protect employees from exposure
to radioactivity. We also have robust procedures and training
for all staff who handle radioactive materials.
We monitor the exposure of employees to radiation and radioactivity.
The standard unit of measurement is a sievert (Sv). A milli-sievert
(mSv) is one thousandth of a sievert, and a micro-sievert
(µSv) is one millionth of a sievert. Legal exposure limits
vary in different countries. For example in the US the maximum
dose is 50mSv per year, whereas in the UK, Europe and Japan
it is generally 20mSv per year. Despite different national
legislation, our goal is to keep all whole body doses worldwide
to below 20mSv.
We were in compliance with all legal limits during 2000 and
2001.
The charts show:
- Maximum dose The
highest amount of radiation received by any single employee
over the course of one year.
- Collective dose The
total amount of radiation received by all employees over
the course of one year.
Group exposure levels
The maximum dose differs between regions but has remained
below our goal of 20mSv over the past five years (except in
the US during 2000). We are working to reduce exposure levels
in countries where they are highest.
The overall collective dose has remained stable over the
past five years but there are regional differences due to
variations at our facilities and production levels.
The majority of employees received less than 5mSv per year
in 2001. Fewer than 2% received doses in excess of 15mSv and
nobody received a dose above 20mSv in 2001
(See Table 01, Graphs 13
and 14).
UK exposure levels
Historical trend In the
UK the maximum individual dose has been reduced by over 60%
from 21.2mSv in 1990 to 7.7mSv in 2001. This remained well
below the UK legal limit which was 50mSv (until the year 2000)
subsequently reduced to 20mSv. The reduction in the individual
dose was not achieved as a result of spreading the total dose
amongst a larger number of people.
(See Graphs 15 and 16).
US exposure levels
Historical trend In the
US there was a large drop in the maximum and collective doses
in the early 1990s due to changes in work practices. The subsequent
increases since 1997 reflect increased workload and fewer
employees.
An incident occurred in one of our US pharmacies in 2000
resulting in a total exposure of 27mSv in that year to an
employee. Local procedures were revised to prevent such an
incident occurring again. Two other employees also accumulated
doses marginally in excess of 20mSv during the year. In 2000
we therefore failed in the US to meet our goal to keep doses
below 20mSv but remained within the US legal limit of 50mSv.
(See Graphs 18 and 19).
Exposure levels to the public
As well as reducing levels of exposure to all of our employees,
we also aim to minimise any exposure to the communities around
our sites. The Food Standards Agency in the UK has estimated
that the typical impact on a member of the public is a dose
of less than three to around 5µSv at our Cardiff and Amersham
sites. The impact is even lower at other sites using radioactive
materials. The average total background radiation to which
members of the public in the UK are exposed is about 2,600µSv.
(See Graph 17).
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