Each agency received a monthly prompt to
complete a specially designed reporting form
for all incidents or to provide “nil returns”. The
variables collected were date; nature and location
of incident; the source of initial notification;
other agencies involved, the numbers
exposed and with symptoms, chemicals released,
and details of environmental monitoring
and health surveillance undertaken. In
most incidents actual numbers of people who
were or who might be exposed could only be
estimated roughly as biomarker surveys of
exposure and dispersion modelling are seldom
carried out. Therefore we have recorded the
estimates made by local responders of the
numbers of people at risk of exposure.