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Case No.4
Skin exposure to hazardous radiation
during
X-ray leakage tests |
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[Circumstances of Incident]
An inspector was suffered hazardous
radiation
exposure to his skin while conducting
X-ray
leakage tests at the final stage in
the manufacture
of an X-ray device.
The company carried out pre-shipment
tests
of manufactured X-ray devices in a
controlled
area within the plant. Detailed inspections
were conducted in terms of both hardware
and software in accordance with the
checklist
developed by the company.
On the day of the accident, the victim
was
engaged in pre-shipment tests on X-ray
diffraction
devices in the test area described
above.
The victim started X-ray leakage tests
from
at bout one o'clock in the afternoon.
He
released a fail-safe mechanism (which
turns
off the X-ray power supply switch if
the
operator opens the front door of the
device),
and measured X-ray leakage with a survey
meter after confirming that X-ray radiation
is continuing. At 1:30 in the afternoon,
as X-ray leakage exceeding the permissible
standard was detected near the right
shutter.
When he tried to inspect the shutter
that
covers the X-ray generator unit, his
right
hand was exposed to hazardous radioactive
X-ray radiation.
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[Causes]
The direct causes of this accident
may be
attributed to the victim's actions.
He released
the fail-safe mechanism of the X-ray
generator
and inserted his right hand into the
radiation
path to remove the shutter covering
the X-ray
source.
This operation involves high risks,
as the
test must be conducted after releasing
the
fail-safe mechanism which contrasts
with the operation by end users. For
this
reason, operational standards must
be established
in advance for trouble involving the
shutter
(for example, procedures to remove
the shutter).
However, such standards were not adopted
by this workplace .
The indirect causes of this accident
relate
to daily operational practices in this
plant.
As inspectors had to handle a large
number
of inspections in professional areas,
they
are assumed to have paid less
attention
to the dangers of X-ray radiation.
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[Type of business] Other precision machines/equipment manufacturing
[Type of accident] Contact with hazardous substances, etc.
[Number of victims] One injured (involving absence from work) |
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