Company officials acknowledged on Saturday
that a
steam leak in a sulphur tank at the
refinery caused
the release into the environment of
hydrogen
sulphide, a highly toxic compound known
in Thai as
gas khai naow because it often smells
like rotten eggs.
Humans who breathe it may suffer from
headaches,
coughing, burning and discomfort of
the chest,
nausea and vomiting, and throat and
eye irritation. If
inhaled in sufficient quantities, it
causes people to
fall into a coma and die of lung paralysis.
Villagers at Haad Sai Thong live quite
close to the
refinery's sulphur tanks, their nearest
houses only a
couple hundred metres away, beyond a
chain-link
fence.
Niels Fabricius, the executive director
of Rayong
Refinery Co Ltd (RRC), a joint venture
between
Shell and the Petroleum Authority of
Thailand (PTT),
said tests carried out by the company
suggested
that the amount of poisonous gas released
by the
leak was well under minimum safety standards.
But the leak was only discovered by company
officials in July, following villagers'
complaints of bad
smells. RRC does not know when the leak
began
''sometime in June or July", Fabricius
said. The first
reports of serious illness among villagers
living
around Map Ta Phud occurred in mid-June.
In a statement released by the company,
Fabricius
attempted to answer the question of
why the leak
was discovered so late: ''I can only
state that this
was a very regretful incident, that
it should not have
happened and that it showed a weakness
in our
environmental management system."
Suphat Wangwongwattana, director of the
Pollution
Control Department's air quality management
division, said that villagers living
near the refinery
suffered from nausea, vomiting and headaches.
''It's
possible these illnesses were caused
by the leak of
hydrogen sulphide," he said. ''It happened
around
the same time."
Public health officials in Rayong, however,
are still
unsure what agent has caused the respiratory
illnesses. Virah Mavichak, deputy director-general
of the Industrial Works Department,
said the
problems are probably the result of
exposure to
several different kinds of toxic gases
emitted by
factories on the estate.
Following the complaints, environmental
officials
have so far investigated 17 of the estate's
52
factories, and ordered six of them
including RRC
to make significant changes to their
waste
treatment systems, Suphat said.
''It's the responsibility of the Industrial
Estates
Authority of Thailand [IEAT] to control
these
factories," he said. ''But they have
not been strict
enough on environmental issues."
Dr Sarawoot Chayovan, deputy governor
of the
IEAT, agreed. ''We accept that we have
not been
strict enough," he said. ''A slight
decrease in our
efficiency has a big impact on the people.
It's a big
problem, so we need the villagers to
come in and
work with the government and the private
sector and
make sure things are working properly."
Yuthana Phuchong, a leader of the villagers,
said he
is satisfied to a certain extent with
the mitigation
actions being taken. But although some
of the
medical problems have eased, he added,
manypeople are still
suffering from respiratory ailments.
Most of the attention has focused on
the students
who have fallen ill at the Map Ta Phud
Panpittayakom school, located near the
Star
Petroleum Refining Company (SPRC), which
is
slightly to the north of Rayong Refinery
in the Map
Ta Phud estate.
Tim Coombs, the general manager of SPRC,
which
is a joint venture between Caltex and
the PTT,
acknowledged that technical problems
at the plant
caused the release of sulphur dioxide
gas into the
atmosphere at levels exceeding Thailand's
safety
standard in June 1996 when plant
operations
began and March of this year.
SPRC has not had
any hydrogen sulphide leaks, he claimed.
But Suphat said the main problem at SPRC
are the
fugitive gases being released from tanks
which
store the refinery's crude oil, sulphur
and waste
water. The company hired an environmental
consultant in February, which came up
with 16
measures to reduce these gaseous emissions.
At
the PCD's orders, those measures are
now being
implemented immediately, at a cost of
US$5
million, according to Coombs.
Rayong Refinery has also taken steps
to reduce its
gaseous emissions. Upon discovering
the steam
vent leak, which was caused by a construction
defect, the sulphur tank was taken out
of operation,
emptied and repaired. But the key question
is: how
much hydrogen sulphide was released?
Suphat thinks the amount might have been
small,
because the tank contained liquid sulphur
which
had already been ''de-gassed". But the
leak would
have caused steam to pass through the
liquid
sulphur, stimulating the release of
any remaining
gases, which would then have vented
out untreated
into the atmosphere.
RRC's Fabricius claims the largest amount
of
hydrogen sulphide it detected escaping
from the
tank was seven parts per million (ppm).
According
to occupational health standards, he
said, people
can work continuously for 40 hours a
week while
exposed to 10 ppm without damaging their
health.
A leak, however, could have caused people
to be
exposed around the clock. Also, hydrogen
sulphide
is often emitted in massive bursts:
it has caused
many sudden fatalities among sewage
workers
when they lift up manholes, and workers
on oil rigs
who drill wells into sulphur-laden oil
fields.
Fabricius noted that hydrogen sulphide
can only be
smelled by humans at levels above 30
parts per
billion and below 100 parts per million.
At levels
above 1,000 ppm, it causes death within
minutes.