the toxic truth - Greenpeace

32 Amnesty internAtionAl And greenpeAce netherlAnds
Chapter 2
The first caustic wash at sea was completed
by mid-April 2006. 79 The Probo Koala then
returned to La Skhirra, Tunisia to unload the
newly “washed” gasoline. Despite having
previously told Univar that the hazardous
waste from caustic washing would be
disposed of at La Skhirra, 80 Trafigura had no
intention of delivering the waste in Tunisia.
tHe caustic wasHing on Board tHe Probo Koala
Trafigura decided to carry out caustic washing
on board the Probo Koala at sea after
running out of options to do it on land. To
carry out this operation, Trafigura arranged
for shipments of the coker naphtha to be
delivered to the Probo Koala. This took
place in ship-to-ship (STS) operations in the
Mediterranean. Ships coming from the USA
delivered coker naphtha to the Probo Koala.
Trafigura then organized for caustic soda to
be delivered to the Probo Koala – again in
STS operations. The first washing of coker
naphtha on board the Probo Koala was carried
out offshore near Malta in April 2006. 73
A London-based executive of Trafigura later
described the process as follows:
“ ... We performed a full STS [shipto-ship]
operation to the Mt Probo koala,
... thereafter we added 50.000 litres
(50cbms) of Caustic Soda (Material data
Safety Sheet attached) proportionately
across all cargo tanks of Mt Probo koala
(using an injection pump/hoses to the
upper level of the coker naphta from the
top of the tank), thereafter circulated
for 24hrs (by transferring individual tank
quantities to an empty tank to achieve the
maximum inter-surface contact between
Naphtha and Caustic Soda) and allowed the
Naphtha and Caustic to separate/settle
and thereafter drained the “Used” caustic
to the slop tanks.
In order to ensure that all of the caustic
was stripped from the treated coker
Naphtha, we stripped more than the
quantity of caustic added originally to
each cargo tank, to make best efforts that
all caustic was stripped thus to ensure
this may also strip some of the treated
naphtha or any free water to the Slop Tanks.
Thereafter (..) treated Naphtha on board
was used as a blendstock to make finished
Gasoline. ” 74
The available evidence shows that some
200 tonnes of caustic soda was transferred
to the Probo Koala in STS operations over
the period between April and late-June
2006. As 50m 3 of caustic was added to
each of the three batches of coker naphtha
at least 150 tonnes of caustic soda was
used for the washing operations. 75
As well as the caustic soda, Trafigura added
a catalyzing agent to some of the washes.
Internal documents show that Trafigura
experimented with the amount of oxidizing
catalyst used, probably in an effort to optimize
the reduction of the mercaptan sulphur
of the naphtha. While no catalyst was used
for the washing of the first coker naphtha
load, 8kg of an oxidising catalyst was used
for the second shipment, and 16 kilo for the
washing of the third shipment. 76
A report commissioned by Trafigura from a
consultancy company, Minton, Treharne &
Davies Ltd shortly after the dumping, noted:
“ In our view the exercise onboard the
Mt Probo Koala was an attempt to replicate
this refinery process [Merox reaction] at
77 sea. ”
This view was later echoed by the Dutch
courts, which stated:
“ […] this essentially boils down to the
moving of an industrial process from land
78
to sea. ”
In fact, Trafigura specifically instructed the
captain of the Probo Koala not to disclose the
presence of the waste at La Skhirra, stating in
an email:
“ PLS ENSUrE ThaT aNY rEMaININGS oF
CaUSTIC SoDa IN ThE TaNkS’ INTErFaCE
arE PUMPED INTo ThE SLoP TaNk To