Case No.5
Chemical burns to skin by contact with
high-concentration raw liquid phenol while taking countermeasures against
abnormal reactions in the synthesizing reaction process for
phenol |
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[Circumstances of Incident]
This accident occurred in a phenol resin manufacturing plant,
where the phenol resin synthesis process included: mixing raw phenol with
acid in a reaction vessel; adding formalin while heating the raw material;
and adding denaturant prior to completing the reaction process by steam
heating. Phenol resin is then produced by dehydration.
A team consisting of a supervisor and four
workers was scheduled to work from 11:00 in the evening to 8 o'clock the
next morning. Trouble occurred during phenol reaction process. As
temperatures in the reaction vessel rose to an excessive level due to
operational mistakes by workers, cooling operations were started. However,
other mistakes in the cooling process resulted in foam resin (an
intermediate product) adhering to pipes and a wide range of other
equipment. Although the foam resin was removed, there was another serious
mistake by the supervisor. When the supervisor ordered the cover of a
check valve to be opened for cleaning at around 10:30 in the morning,
dehydration liquid spouted from the valve. Four workers who were engaged
in this emergency operation were injured when their skin was burned by the
high-concentration phenol.
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[Causes]
The
direct causes of this accident may be attributed to the supervisor's
erroneous instructions to clean the check valve instead of cleaning a
strainer contaminated by foam resin due to trouble during the phenol resin
synthesis process. Dehydration liquid containing high-density phenol
spouting from the valve injured four workers
Although the supervisor and four workers knew about the
presence of the check valve, but had no knowledge of its structure and
functions. This is why they mistook the valve as the strainer.
Moreover, while workers were wearing
protective masks and rubber gloves, their clothing was made of cotton
rather than impermeable protective fabric. As a result, they sustained
injuries on their necks, bodies, arms and legs.
The indirect causes of this accident relate to the
following: (1) An instruction book covering
this operation indicated no clear instructions on vacuum adjustments,
leading to rapid increases in the temperatures in the reaction vessel due
to a worker's erroneous operations. Thus vacuum cooling is required to
correct the situation. (2) When proceeding with
the vacuum cooling, workers mistakenly switched over to "dehydration
piping" as they normally do during the resin transport process, thus
requiring the cleaning of the strainer and other
equipment.
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[Type of business]
Inorganic/organic chemicals manufacturing [Type of accident] Contact
with hazardous substances, etc. [Number of victims]Four injured (involving
absence from work) |