The EUROCRUDE system of oil fingerprinting was developed to improve the success of scientific methods in identifying the perpetrator of oil spills. Scientific methods and a forensic approach were combined to develop a fingerprinting system that would provide results able to uniquely identify the perpetrator and be sustainable in legal proceedings. Although developed for crude oil identification, the principles of EUROCRUDE can also be used to fingerprint bilge discharges and some refined products. An overview of EUROCRUDE, its application to various spill incidents, the conclusions derived from the analyses and ensuing court proceedings are described.Abstract
The EUROCRUDE system of oil fingerprinting was developed to improve the
success of scientific methods in identifying the perpetrator of oil spills.
Scientific methods and a forensic approach were combined to develop a fingerprinting
system that would provide results able to uniquely identify the perpetrator
and be sustainable in legal proceedings. Although developed for crude oil identification,
the principles of EUROCRUDE can also be used to fingerprint bilge discharges
and some refined products. An overview of EUROCRUDE, its application to various
spill incidents, the conclusions derived from the analyses and ensuing court
proceedings are described.
Oil and oil products are recovered, transported and transferred in large quantities
through the world. The pollution of the marine, coastal and harbour environments
by these products continues to be an issue around the globe. Areas of the Danish
coast are continually affected by crude oil pollution. The pollution might arise
by natural seepage from the sea floor, but typically it occurs as a result of
an accident, such as a well, shipping or bunkering incident, or by deliberate
discharge from the bilges of vessels.
Bilge discharges are subject to the MARPOL Regulations. A discharge that is
in compliance with these regulations should neither lead to pollution of the
shoreline nor to visible oil on the feathers of seabirds. Discharges that contain
high concentrations of oily material are illegal and the perpetrator might be
sought. Responsibility is sometimes declared without recourse to evidential
proof, but evidence of culpability is generally required.
Legal proceedings may follow and the desire for successful court prosecutions
has been a strong driver to improve the efficacy of means to identify the culprit.
I am not going to talk about cases where the responsible party is patently
obvious because a ship has run aground, or you have eye witness accounts and
photographic evidence of oil running down the side of the ship. But even then,
the concept of an oil spill fingerprint and forensic evidence has its uses.
For example, in the Exxon Valdez incident, oil spill fingerprinting showed that
Prince William Sound was not the pristine environment it was thought to be.
Oils from other sources were present, including those from historical accidents,
commercial boating traffic and natural seepage of oil from the sea floor. This
might have consequences for determining the extent of liability and charges
Oil is a complex mixture of chemicals. It reflects the origin of the materials
from which it was made and the geological, geochemical and other processes it
has undergone. Crude oils are formed from vegetative material, be this land-based
plants or water-based plants such as algae. Plants are veritable chemical factories.
They make a wide variety of different products – some are plant specific, some
in common with other plants but in different proportions between different plants.
The composition of a crude oil is therefore dependent on the plant life at
the time of sedimentation. Different flora in different areas gives a different
mix of chemicals.
There are then the modifying geological and geochemical factors that give a
crude oil from any one source its particular characteristics. Exposure to oxygen,
pressure and temperature affect the chemical processes that occur in the formation
of the crude oil and its maturation. There are filtering and chemical sorting
processes that occur during the migration from the source rock to an underground
reservoir, a path that may be kilometres long. And, there are the changes that
occur by biodegradation, water washing, mixing, and relative mobility issues
in the reservoir.
Although superficially similar, there would seem to be great potential to develop
an oil fingerprint and uniquely identify an oil and provide forensic evidence
in oil spill cases to prove or disprove a vessel as the source of a spill. This
has been the subject of scientific study for many years, and a raft of chemical
tests have been applied to crude and refined oils in an attempt to do just this.
You may have heard of scientific techniques such as UV fluorescence, Infra
red spectroscopy, nickel/vanadium ratios, iron, copper and /or sulphur content.
In practice, these tests are of low discriminating power – they are not
good at telling you when oils were different or narrowing down the field of
Hydrocarbon profiling is a more useful technique. Oils are about 75% hydrocarbons,
there are many different individual hydrocarbons, and the hydrocarbon distribution
can be used to profile and identify a product type, for example, petrol and
diesel. It can also distinguish between some of the different fuel oils and
some of the crudes.
For spilled products, the situation is more complicated. Spilled oils spread
out to cover large surface areas, many of the hydrocarbons are very volatile,
oil components can dissolve in the water, chemical changes can occur on exposure
to sun and air, biochemical degradation can occur, and these is the possibility
of contamination by other products. The spreading of the oil can accelerate
the rate of all these processes. The longer the spilled product is in the environment
the more difficult it becomes to identify or exclude vessels as possible suspects
in a spill incident using hydrocarbon profiling.
The evidence available for legal proceedings using these techniques is often
along the lines of “could have come from this ship”, “cannot
exclude the possibility it has come from another ship”, “can’t
tell whether it has or has not come from this ship”, and so on. Many may
have seen the legal adjudicator err on the side of caution, the result being
no prosecution, when there is no useful forensic scientific evidence.
Apart from the chemicals mentioned so far, petroleum oils also contain a diverse
and complex group of chemicals known as biological markers, or “biomarkers”
in short. These are natural chemicals formed by the plants and cannot be made
artificially by man. There are some 100 biomarkers, and even though they are
present at only very low concentrations, their complexity and the natural variations
in their relative proportions potentially could provide a unique fingerprint.
With advances in scientific capability, there have been attempts to develop
formal systems of fingerprinting, and until recently the most advanced of these
was the NordTest method. This was developed in 1983 by 5 Nordic laboratories,
and later modified. The focus was successful prosecution, recognising that the
scientific evidence would not necessarily identify the offender, but was an
important part of the legal process. The method considered forensic evidence
requirements and came with detailed recommendations for sampling, handling samples,
transport, chain of custody, storage and analysis procedures. Analysis was by
standard scientific methods that had been available for some 10 years prior
so court acceptance was not an issue.
The NordTest method was devised for water borne oils, and could analyse small
volumes of spill. It was suitable for crude and refined oil products with boiling
points higher than kerosene at 200?C. This did not mean that you couldn’t
do an analysis on the lighter products. Rather, the reliability and efficacy of
the testing is much reduced because the chemical patterns are much simpler, have
smaller differences between them and the problems of evaporation and water washing
were much more significant.
The NordTest took a tiered approach using a hydrocarbon profile for initial
testing and to separate those sources that were not responsible for the spill
from those which might be. It then looked at 29 different biomarkers that were
either not affected by weathering, or were affected predicably to try to reach
a more definitive conclusion. Weathering, if an issue, could be taken into account
with a mathematical calculation.
The NordTest advanced the use of forensic scientific evidence and the interpretation
of results in oil spill cases. In conjunction with other evidence, it could
identify the perpetrator of a spill – as usual, where there was any doubt it
went in favour of the suspect. It became and important part of the legal process
in some countries despite not being able to provide a unique fingerprint. Another
of the limitations was that it remained necessary to have a sample of spilled
oil and samples from a suspect ship.
Enter the EUROCRUDE system of fingerprinting. EUROCRUDE was an attempt to achieve
a more effective identification and to work in those cases where there was no
suspect ship. It was developed through the collaboration of 6 European countries.
It recognised that there had been advances in scientific capability since the
NordTest was developed, and there was greater accessibility to computers and
software packages for statistical analysis and comparisons.
The goal was to develop a database of fingerprints for crude oil produced or
transported in European waters, at least in the first instance, and to evaluate
or develop statistical methods and computer software for comparing and matching
fingerprints in a database.
The biomarkers were the focus of interest and the team went thorough an extensive
exercise by testing many different crude oils to identify which of the biomarkers
would enable them to produce a fingerprint and the highest evidential value.
As part of this they developed standardised methods that would give reproducible
fingerprints suitable of use in a database and which any laboratory with the
appropriate scientific instrumentation could use. The revisited the effects
of weathering and decided which biomarkers were most effective for weathered
The result? They found that fifty six biomarkers provided a fingerprint sufficient
to identify the country and oil field of origin. Sometimes it could even identify
the oil well of origin. It also used biomarkers with greater resistance to weathering
so time delays between spill and sampling would not be crucial. This meant that
even when the vessel was long gone from the scene, shipping records could still
be used to identify the culprit. It was not necessary to have samples from the
ship as the records could identify which ships were carrying what crude, where
they were bound, and therefore whether they were potentially in the area at
the time of the spill.
Again there was no new science so court acceptability was not an issue –
the methods have been in use for oil exploration work and scientific testing for
some time. It also worked for refined products and was more effective than the
NordTest as it used a larger number of biomarkers to form the fingerprint.
And, also importantly, it was discovered that the biomarkers in a vessel’s
bilge contents and discharge are also a fingerprint of the ship. They reflect
the history of the ship – the products it has carried and used over time.
So by comparing “fingerprints” of different spilled oils with material
from the bilges of ships, it is possible to determine from which ship a spilled
oil came. For this work, samples from ships are required for analysis. And,
like the NordTest method, hydrocarbon profiles can be used in the first instance
to separate suspect ships into “eliminated” and “possible”
Again, it must still be evident that despite the advances in the power of method,
science doesn’t do it on its own. It is only a piece in the jigsaw of
any puzzle or case to solve which ship is responsible or not responsible for
a spill. The scientist must work in conjunction with others to build the case.
And so I am now going to pass Captain Robin Keer-Keer, Harbour Master at Environment
Canterbury, New Zealand, to describe a case where the principles of EUROCRUDE
were applied to a spill and a guilty plea was entered in court proceedings.
It was a blustery cold Saturday morning at 0700 on Saturday 3rd August 1997
in mid winter with a southerly wind blowing at 30 knots after the passage of
an active cold front. The air temperature was 4?C, with moderate rain and at
times sleet. The on duty pilot rang to report an oil spill in the Lyttelton
inner harbour in the area of number 2 wharf and the tug and ferry wharves.
The pilot tells me there is a lot of oil around and he has put the pilot launch
crew on standby. His description of the spill is ‘thick black oil.’
I was still in bed listening to the radio news! This was not the kind of news
I wanted to hear about.
Environment Canterbury has a small, trained team of staff to respond to the
environmental cleanup and the investigation and evidence gathering from a possible
With my ‘Environment’ hat on I realised it was in our interest
to get on site as soon as possible, especially with the air temp being as low
as 4?C. and the sea temp being about 8?C – 9?C. The effective window for
a dispersant clean up was not going to be open for very long and the wind would
make the water choppy.
On arrival at the spill site, the first small pointer in our favour became
apparent in an otherwise cold and wintry day. The Southerly wind had driven
the oil in front of it and confined it to a small surface area, under the wharf
and against the shoreline.
This made collection of sea samples quite quick and simple. The rubber hoses,
which were connected to a high-pressure water supply on the wharf, could reach
it. They were able to mix dispersant by way of a venturi suction pipe from a 20-litre
container, and spray it onto the sea surface.
Cleanup commenced as soon as sea samples were obtained. They were given a unique
number, labelled and put in secure stowage in Schott glass laboratory bottles.
The cleanup operation commenced at 0900 and continued until 1400 hrs. A launch
was also used to get at some of the awkward places the oil had managed to find
its way into.
The second phase of this operation was the evidence gathering and if possible
locating a source of where the oil had originated from. From handling the oil
when obtaining the sea samples, the smell and feel of the oil, I estimated the
oil to be light fuel oil rather than gas or lube oil.
Looking around the harbour for what vessels were in the area of sufficient
size to burn light fuel oil in their main engine, I was able to eliminate the
tugs, small fishing vessels and a passenger commuter ferry, as they were all
diesel powered. This left four foreign trawlers each about 85 metres in length
overall within the possible area.
I took the pilot vessel to go around the harbour and examined the seaward side
of each vessel for any signs of an oil overflow, and found nothing.
The sampling started on the vessel directly upwind. I got the agent on board
and interviewed the Master and Chief Engineer, explained that there had been
an oil spill in the harbour and asked if their vessel had been responsible for
the spill. In all vessels visited the staff said they had no knowledge of the
spill and the oil had not come from their vessel.
We requested the ship’s staff accompany us while samples were obtained
from the pumps and bilges on each vessel – this amounted to three pumps per
vessel plus samples from the engine room bilge. All four vessels were sampled
and these samples together with samples from the sea were sent for oil fingerprint
analysis to see if a match could be found.
Two vessels were quickly eliminated using hydrocarbon profiling as not being
in any way connected. A further level of tests and analysis was carried out
using the EUROCRUDE biomarker method for the remaining two vessels.
An oil fingerprint match was obtained to one of the vessels and the case went
to court. The scientific evidence was the main evidence, everything else was
circumstantial. The defendant pleaded guilty and was fined $6500 plus cleanup
costs of $5980
Lyttelton Harbour Saturday morning 5th June 1999 at 10.30 a.m. The duty Pilot
calls in that a black oil spill is floating on the sea in an area bounded by
Z berth in Gladstone Pier.
The weather at the time was fine and clear, air temperature 8?C. Good visibility,
Most of the light fuel oil, which was floating on the sea surface, was to be
found under the wharf. There were five ships in the possible area, no recent
shipping movements and a visual inspection of all vessels from the seaward and
wharf side showed no signs of any oil flowing down the side of any vessel.
Three of the five vessels were laid up, rafted alongside each other and with
a crew of six people between them. The fourth vessel was a Russian trawler moored
astern of the three rafted together, these vessels were about eighty-five metres
in length. The fifth vessel was a Chinese squid jigger due to sail from the
port the same day.
Samples were obtained from each vessel from the pump discharges and from the
engine room bilge. Control samples were obtained from the sea and all these
samples were sent for oil fingerprint analysis. A match was obtained from one
of the three vessels rafted together.
The case went to court, on 20th September 1999 a conviction was obtained the
fine was $8000 plus cleanup costs of $5952.
In this case the vessel which pumped the oil into the sea had a clean sample
of seawater from each pump, and it was the sample from the engine room bilge
which provided the evidence required. In my opinion after pumping the oil into
the sea the pump had been changed from bilge suction to sea suction to clean
the pump of any signs of oil. Without the oil fingerprint analysis we would
never have got evidence to the standard required for court. End of story.
In selecting a laboratory for oil spill finger print analysis, the points I
considered in my selection were as follows:-
- A laboratory accredited to an International standard.
- A laboratory with suitable hardware application ( gas chromatic mass spectrometer
- Suitable software available at the laboratory.
- Qualified staff with experience in forensic analysis.
- Clear and definite reports, which a Judge sitting in his court can easily
- Laboratory staff with experience in cross examination in court.
The last point is most important – that the analysis staff is capable
of stating their own opinions and will not necessarily agree with everything
that is suggested to them by cross examining council and thereby creating an
element of doubt. If any doubt exists it correctly belongs to the defence and
the decision will benefit the defence.
Gentlemen you can make all the right moves and have a good case and loose it
under cross-examination through inexperienced laboratory staff. Great care needs
to be taken in selecting the correct team.