Land and Environment Court of New South Wales CITATION : Filipowski v Nikolaos; Pontian Shipping Co Limited [2005] NSWLEC 102 PROSECUTOR Barbara Filipowski PARTIES : DEFENDANTS Kandilis Nikolaos Pontian Shipping Co Limited FILE NUMBER(S) : 50051 of 2004; 50052 of 2004 CORAM: Talbot J KEY ISSUES: Prosecution :- test for proof beyond reasonable doubt based on circumstantial evidence in respect of strict liability offence. LEGISLATION CITED: Marine Pollution Act 1987 s 8, s 8(1) Knight v The Queen 175 CLR 495 ; CASES CITED: Latoudis v Casey (1990) 170 CLR 534; Martin v Osborne (1936) 55 CLR 367 DATES OF HEARING: 28/2/05, 1/3/05, 2/3/05 DATE OF JUDGMENT: 03/11/2005 PROSECUTOR Mr J C Sheahan SC with Mr A L Hill (Barrister) SOLICITORS Dibbs Barker Gosling LEGAL REPRESENTATIVES: DEFENDANT Mr P Byrne SC SOLICITORS Ebsworth & Ebsworth JUDGMENT: THE LAND AND ENVIRONMENT COURT OF NEW SOUTH WALES Talbot J 11 March 2005 50051 of 2004 Barbara Filipowski v Kandilis Nikolaos 50052 of 2004 Barbara Filipowski v Pontian Shipping Co Limited JUDGMENT 1 Talbot J: On 30 April 2002 the defendant in matter No. 50051 of 2004 was the master of the ship Frixos and the defendant in matter No. 50052 of 2004 was the owner of the ship. The defendants are respectively charged, as the master and owner of the Frixos, in respect of a discharge of oil which occurred into the waters of Gore Cove, Port Jackson allegedly in contravention of s 8 of the Marine Pollution Act 1987. Both defendants have pleaded not guilty. 2 Section 8(1) of the Marine Pollution Act 1987 provides:- Subject to subsections (2) and (4), if any discharge of oil or of an oily mixture occurs from a ship into State waters, the master and the owner of the ship, and any other person whose act caused the discharge are each guilty of an offence punishable, upon conviction by a fine not exceeding: (a) If the offender is a natural person – 2 000 penalty units, or (b) If the offender is a body corporate – 10 000 penalty units. 3 Each penalty unit at the relevant date was $110. 4 There is no direct evidence of how the alleged discharge from the ship into the waters of Gore Cove occurred. 5 The prosecutor relies upon lay eyewitness accounts of events and circumstances surrounding the observation of oil on the water in the vicinity of the Frixos and expert evidence that purports to match samples of oil taken from the bilge of the ship and the Heavy Fuel Oil ("HFO") transfer pump with samples of oil taken from the harbour by chemical analysis. Eyewitness accounts 6 On 29 April 2002 Garth George Bennett, an employee of the Sydney Ports Corporation ("SPC") was involved in disconnecting a moveable boom from around the ship Helix at the Shell Oil Terminal at Gore Bay. The removal of the boom from around the ship Helix took place between 1500 – 1630 hours on 29 April 2002. Mr Bennett makes the following statement in an affidavit:- I did not observe any oil on the waters surface, inside or outside of the boom, during that time. If there had been oil on the waters surface in the area of Gore Bay, around the hull of the "Helix" or on route between Gore Bay and Moores Warehouse, Millers Point, I would have observed it and reported its presence to the SPC. 7 Warren Keane was present at the Shell Oil Terminal on 29 April 2002 during the disconnection of the ship Helix from the Shell Oil Terminal until 1530 hours. In his affidavit he gives evidence in identical terms to the last sentence of the evidence quoted above from Mr Bennett's affidavit. 8 Frederick Tagoe, an employee of the SPC, last inspected the ship Helix berthed at the Shell Oil Terminal at Gore Bay at 0545 hours on 29 April 2002. He also made a statement almost in identical terms to that of Mr Bennett in his affidavit. 9 The Frixos transited Sydney Heads at 0635 hours on 30 April 2002 and was all secure at the No.1 Berth, Gore Cove at 0811 hours. 10 The first observations of oil on the water astern of the Frixos were made about 0900 hours on 30 April 2002. William West, an employee of SPC, observed areas of what he described as "small areas of heavy fuel oil on the water's surface in globules" about 20 metres astern of the Frixos. He said that the areas of oil on the water's surface were coming from the stern area of the Frixos within two to three metres around her port quarter. He observed an area of heavy black oil collecting in the curvature of a boom being placed around the ship. He also observed a heavy oil sheen that stretched in a southerly direction back towards Balls Head. He agreed in cross examination that he could not see "oil being discharged from some place on the stern." Another SPC employee, Kevin James Rosser, confirmed the observations made by Mr West. 11 A further employee of the SPC, John Padruig MacDonald Allan, saw black globules of oil on the water's surface coming down from the stern area of the ship Frixos and gathering on the water's surface inside the oil containment boom at about the same time Mr West made his observations. 12 Mr Allan took a clean galvanised fire bucket and dipped it into the water on the inside of the boomed area where the black oil globules had gathered together. He subsequently placed samples of the oily water in clean sample jars and after labelling them locked each sample in a refrigerator. Desmond Patrick Spurrier a Port Officer with SPC confirmed the observations made by Mr West and Mr Allan in relation to the appearance of oil on the surface of the water, its position and the taking of the sample in the galvanised fire bucket. 13 Although oil globules were observed coming to the surface of the water in the immediate vicinity of the port side of the stern of the Frixos no discharge from any point of the ship was observed. 14 Divers inspected the hull of the Frixos on 30 April 2002 and 1 May 2002. The divers noted oil on the flat bottom of the vessel and on the underside of the forward stabiliser fin located slightly aft of one of the lower sea chests. A diver reported that as he moved about the flat bottom his exhaled air dislodged most of the trapped oil, which rose to the surface and dissipated. No point of a discharge was identified by the divers. 15 Mr Byrne SC, who appears for the defendants, relies upon what he says are gaps in the prosecutor's evidence, particularly the time between when the Helix left the berth at Gore Bay at 1630 hours on 29 April 2002 and when SPC employees arrived at Gore Cove between 0800 and 0900 hours on 30 May 2002. No witness says that he actually saw the Helix leave. Nor did any witness observe the arrival of the Frixos or the path that either ship took on the way from or to the berth in Gore Bay. 16 Two SPC employees went on board the Frixos on 30 April 2002 and 1 May 2002 when samples were taken from the engine room bilge, No.7 cargo tank and the HFO transfer pump in their presence by members of the ship's crew. Expert Evidence 17 Dr John Francis Leeder, a qualified Analytical Chemist, received two samples for testing from SPC on 22 and 28 May 2002. Additional samples were received on 21 August 2002 and 1 April 2003. According to Dr Leeder the samples were analysed using approved methods of the American Society for Testing and Materials (ASTM) employing analytical techniques of Gas Chromatography for whole oil analysis. Three samples were selected for biomarker analysis by High Resolution Capillary Gas Chromatography/Mass Spectrometry and elemental analysis. 18 Dr Leeder found that the oil on the water from Gore Bay was a degraded bunker fuel oil. The sample from the bilge of the Frixos was found to contain lubricating oil and did not match the oil spill sample. The samples of HFO from the HFO transfer pump were found to have a perfect match with the spill sample. He said that the perfect match was indicated by the triterpane profile of the samples. 19 He summed up his analysis as follows:- I have reviewed all of the analytical data including the chromatograms from the whole oil analysis and the data from the biomarker analysis. Based on the match between the triterpane biomarkers and the unresolved complex mixture (UCM) I have identified the 'Frixos' as the most probable source of the Gore Bay spill on 30/04/02. The triterpane profiles for the oil spill samples were found to be a perfect match with the Frixos HFO transfer pump sample. This match can be clearly seen in the chromatograms displayed in Figure 3. The probability of this match is 90%. I am therefore of the opinion that the Frixos is the source of the spill due to these similarities observed, to a 90% certainty using the ASTM method but the point of discharge on the vessel has not been sampled from this vessel. 20 Furthermore he found that the samples contained isomers of the unique compound dichlorotoluene ("DCT") and that the presence of these unique isomers in the spill samples and the two different samples from the Frixos, in his opinion, provide a clear link between the spill and the vessel. 21 He expressed his level of certainty in this respect:- Based on the analysis I performed and the presence of these unique isomers of dichlorotoluene in the Gore Bay spill samples and in two different samples from the ship "Frixos" it is my opinion that there is a perfect match between the Gore Bay spill samples and the samples obtained from the "Frixos" with a 100% certainty. 22 Dr Leeder could not be shaken from the level of 100 per cent certainty in cross examination notwithstanding a conclusion inconsistent with his own expressed by Dr Scott A Stout, a Senior Consulting Geo-Chemist from Massachusetts in the United States of America engaged by the prosecutor and Dr Peter James Christopher Tibbetts a Chartered Chemist retained by the defendants. 23 Dr Tibbetts currently acts as a consultant to the company M-Scan Limited, a world leader in mass spectrometry consulting and analysis for chemistry, life science and environmental studies with offices in the United Kingdom, Switzerland, Germany, United States of America and an agency office in South Korea. In September 2004 the samples analysed by Dr Leeder were divided and sub samples were forwarded to M-Scan Limited for the purpose of conducting tests upon the samples to establish the veracity of the assertions made by Dr Leeder. 24 The results obtained by Dr Tibbetts suggested to him that the oil in the Gore Bay water samples had biodegraded since its analysis by Dr Leeder. He formed the opinion that the period of time between the docking operations of the Frixos and the collection of the water samples would not be sufficient to degrade the HFO. Dr Tibbetts described the samples taken from the HFO transfer pump as resembling a fresh heavy fuel oil that has been blended with a kerosene-based "cutter stock", whereas the engine bilge samples could represent a heavily weathered and biodegraded crude or heavy fuel oil or alternatively could represent a lubricating oil. 25 Dr Tibbetts obtained biomarker fingerprints of the spill oil, the Frixos bilge sample and the Frixos HFO transfer pump sample. The results he obtained suggested that the fingerprints are similar. He concluded as follows:- In oil-oil correlation studies a positive match is not necessarily 'proof' that samples are related (Peters and Moldowan, 1993). In contrast, any differences in reliable 'biomarker fingerprint' parameters that are statistically significant, results in the two oils being considered a 'Non-match'. In the present case, there are statistically significant differences in a number of triterpane parameters. These differences, therefore, classify both the Frixos bilge and the Frixos HFO samples a 'Non-match' when compared with the oil from the Gore Bay water. On this basis the statistical differences in both of these oils precluded them as the source of the Gore Bay spill. 26 His analysis of whole oil for DCTs showed an increase in the relative concentration of the DCTs in the spill sample in the time since Dr Leeder undertook his tests. 27 Dr Tibbetts summarised his conclusions as follows:- · The GC traces of the DCM extracts (whole oils) of the oil in the Gore Bay water samples are consistent with those expected for a weathered and biodegraded crude oil or heavy fuel oil. · GC analysis of the whole oils indicate that the spill samples have been subjected to weathering and biodegradation in the intervening time between the analysis by Leeder Consulting in 2002 and the present analysis by M-Scan. This suggests that the storage conditions were not suitable for the prevention of deterioration of the samples. · GC traces of the Gore Bay spill samples are dominated by peaks, which have been confirmed by GC-MS analysis, to be dichlorotoluenes (DCTs). These appear to have increased in relative concentration in the spill samples since the analysis by Leeder Consulting in 2002. It is difficult to envisage a mechanism that would result in an increase in the relative concentration of the DCTs in the sample over time, without addition of these components from outside. · The relative concentration of the DCTs appears to be higher in the spill sample than in the "Frixos" HFO. Due to the higher water-solubility of the DCTs relative to the bulk oil, it is difficult to envisage a mechanism that would result in the increase in the relative concentration of the DCTs in a spilled oil sample. · From a comparison of the GC traces of the oil in the Gore Bay water and those from the HFO transfer pump on the vessel MV "Frixos", the "Frixos" HFO samples cannot be precluded as a potential source of the contamination in the Gore Bay water. However, the degree of weathering and biodegradation in the two Gore Bay water samples would suggest that the oil had been released into the environment several days, if not weeks prior to sampling. It is understood that the vessel MV "Frixos" had not completed docking operations when the oil spill was observed. This period of time would not be sufficient to degrade fresh HFO to the extent seen in the Gore Bay waters. · GC-MS analysis of the PAHs in the Gore Bay water sample and the Frixos bilge sample has shown that these parameters have been affected by weathering to such an extent that the normal diagnostic ratios have been rendered unusable. · GC-MS 'fingerprinting' of the samples indicates that there are statistically significant differences in a number of triterpane diagnostic ratios, which classify both the "Frixos" bilge and the "Frixos" HFO samples as 'Non-matches' when compared with the oil from the Gore Bay water. On this basis, therefore, both of these oils can be precluded as the source of the Gore Bay spill. 28 Dr Stout was retained by the prosecutor to review the chromatographic and tabulated data contained within the reports of Dr Leeder and Dr Tibbetts. 29 He collectively considered data from both the Leeder and Tibbetts reports to develop his interpretation as to the chemical nature of the Gore Bay spill samples and the Frixos candidate source samples. It his opinion that the existing data contained within the Leeder and Tibbetts reports are of sufficient quality and extent to reach a defensible conclusion as to the relation between the samples. 30 Contrary to the opinion of Dr Tibbetts, Dr Stout opined that the degree of weathering observed in the Gore Bay oil sample is not inconsistent with what would be expected in a recently released heavy fuel oil. 31 Dr Stout offered a series of alternative explanations for the higher relative concentrations of DCTs apparent in the M-Scan data than in the Leeder data but in the end emphasised that the most important point is that the DCTs truly were present in the Gore Bay spill samples and the Frixos candidate source oils. He concluded that the variation in DCT abundance in the spill and bilge oils was due to sample preparation method and not to any external source of DCTs to the sample. 32 Dr Stout observed that on average many of the biomarker based diagnostic ratios for the Gore Bay spill oil have values that are in between those of the Frixos HFO and bilge oil. In his opinion this clearly reveals that mixing of the two Frixos oils might have produced the Gore Bay spill oil. 33 Dr Stout agrees with Dr Tibbetts that the two Frixos source candidates were "non-matches" for the Gore Bay spill oil and therefore could be "precluded as the source of the Gore Bay spill". However he has explained that the Nordtest methodology relied upon by Dr Tibbetts acknowledges that when mixtures are suspected "a simple linear mixing algorithm could be developed to explain the oil spill". Therefore according to Dr Stout, as Dr Tibbetts did not consider a mixture, he did not complete the Nordtest analysis. This he says is a severe shortcoming in circumstances where the Gore Bay spill oil had exhibited values in between the two Frixos candidate source oils. In his opinion the recommendation in the Nordtest method is appropriate in this instance. 34 Dr Stout chose to assess the potential for mixing by using two qualitative methods that each made an assumption with respect to biomarker concentrations in the samples. It was not possible to develop a quantitative linear mixing algorithm in the absence of biomarker concentration data or sufficient information to calculate these concentrations. Dr Stout described the reliability of the outcome of the qualitative methods as follows:- Because each method required that an assumption be made, neither method should be considered as being quantitative in the sense that the "answer" reflects the absolute volumes of each oil in the mixture. However, it is very important to understand that an absolute "answer" (e.g., " X-percent HFO and Y-percent bilge oil ") is not necessary to defensibly establish if a mixture of the Frixos candidate source oils can provide a "positive match" (sic) the Gore Bay spill oil. Both methods simply are different mathematical approaches to testing this possibility – any "answer" that provides a match to the Gore Bay spill oil is proof that a mixture was possible (regardless of the absolute percentages). 35 Moreover both methods by which the M-Scan data were evaluated demonstrated to Dr Stout that mixing of the two Frixos candidate source oils could achieve a "positive match" with the Gore Bay spill oil. According to him both methods achieved a result of approximately 70% HFO and 30% bilge oil. He says that if different assumptions had been made the only impact would be that a different "answer" would be achieved – but a "positive match" by the Nordtest Method would still result. Dr Stout concluded that the linear mixing analyses conducted by him are proof that a mixture of the two Frixos candidate source oils would yield a "positive match" to the Gore Bay spill oil. 36 Despite the lack of direct evidence Dr Stout expressed the view that "it is more likely than not that the presence of DCTs in the three oils samples are the results of a particular solvent used onboard the MV Frixos". His opinion is that the DCTs provide additional support to the Nordtest method's results that the Frixos is the source of the Gore Bay spill. 37 The following extracts from the summary of his opinions reflect the essential findings by Dr Stout:- · Qualitative inspection of the biomarker distributions reveals features in all three of the oils studied typically associated with oils derived from carbonate source rocks. More importantly, multiple biomarker features in the Gore Bay spill oil on average are in-between the two candidate source oils from the MV Frixos. The apparently intermediate character of the Gore Bay spill oil is evident in the biomarker-based diagnostic ratios reported by Dr. Tibbetts. As per Nordtest methodology, this observation warranted development of a linear mixing algorithm. · The correlation analysis component within the revised Nordtest method is unable to deal with mixed sources because it only allows comparison of one source sample at a time against the spilled oil. However, the method clearly states that when a mixture of source oils is suspected to be the source of an oil spill "a simple linear mixing algorithm could be developed to explain the oil spill". The mixed oil can then be compared to the spill oil using the method's correlation analysis component. · Dr Tibbetts' application of the revised Nordtest methodology to the M-Scan data was appropriate, but incomplete. Using the linear regression-correlation analysis component of the method he correctly concluded that individually the Frixos HFO or bilge oil were each "non-matches" to the Gore Bay spill oil. However, Dr Tibbetts failed to consider the potential for a mixture of these two source oils, which given the many intermediate features exhibited by the Gore Bay spill oil, was fairly obvious. Therefore, consideration of a mixture of the two source oils was necessary to complete the Nordtest method. Dr Tibbetts did not do so. · As recommended in the revised Nordtest method when mixtures are suspected, two different qualitative linear mixing algorithms were developed using the same biomarker-based diagnostic ratios and data utilized by Dr Tibbetts. Both methods demonstrated that a mixture of the Frixos HFO and the bilge oil candidate source oils would produce an oil that, also according to the revised Nordtest method, was a "positive match" with the Gore Bay spill oil. · Mixed isomers of DCT are commercially used in solvents marketed to the maritime industry. The specific DCT isomer pattern can vary between solvents. The DCT isomer pattern in the Gore Bay spill oil is comparable to the DCT isomer pattern in the Frixos source oils. Thus, it is far more likely than not that the DCTs in the Gore Bay spill and Frixos source samples studied are derived from a particular type of solvent used onboard the MV Frixos. The DCTs' presence in the Gore Bay spill oil and both of the Frixos source oils provide further support to the revised Nordtest method's "positive match" results and further indicates that the Frixos was the source of the Gore Bay spill. · Collectively, the chemical data available provide overwhelming evidence that the MV Frixos was the source of the Gore Bay spill oil observed April 30, 2002. 38 In cross examination Dr Tibbetts said that his instructions were to compare the oil from the water to see if it matched either the oil from the HFO or the bilge, rather than to answer the question whether the oil in the spill sample was likely to have originated from the Frixos. Mr Sheahan SC, counsel for the prosecutor, submits that this would explain why Dr Tibbetts did not progress to a consideration of a mixture of the two source oils. 39 Following a challenging discussion regarding the proportion of water in the samples analysed at M-Scan, as well as the impact of water on biodegradation and after referring to the development of a blending logarithm by Dr Stout, the following exchange took place between Mr Sheahan and Dr Tibbetts:- Q Looking at that data, I suggest, and having regard to what was described in the article that we've just been to, what you should have done, if you were attempting to the best of your ability to assist the court in this matter, was to follow through your investigation to see if a blending logarithm could be developed to explain the spill; do you agree? A . Solely on this data, that's the case. In my mind, I had already excluded the bilge sample as a source of the spill due to the difference in the GC analysis. Q . You have read the analyses that appear - that is the mixing analyses - at pages 14 and 17 of Dr Stout's report; correct? A. Yes, I have, yes. Q . And you have seen, if I can take you to it, the histograms, which appear at page 36 of his report? A . Yes, I've seen them. Q . And you have seen the correlations, which he has plotted on page 37? A . Yes. Q . That is of his two methods of assessing the hypothetical 30 per cent or 30 per cent/70 per cent mix of the two Frixos samples? A . Yes, I've seen those. Q . That analysis strongly suggests, does it not, that the source of the oil in the spill sample is to be explained as a blend of components, which appear in the heavy fuel oil and bilge from the Frixos? A . It shows that the theoretical mix is - the match between the theoretical mix and the Frixos is possible. It is a positive match. Q . And if one were to combine with that circumstance reflection upon the singular fact of three identical dichlorotoluene isomers being present in Dr Leeder's original analysis of each of the three samples, the appropriate conclusion, is it not, is like Dr Stout's that the overwhelming evidence overall is that the Frixos was the source of the spill? A . It looks probable from this data, but I still have some doubts over the dichlorotoluenes. 40 Dr Brian King is an Oceanographer engaged by the prosecutor to estimate the quantity of oil released into the waters of Sydney Harbour on 30 April 2002 and to undertake an analysis that would indicate the mostly likely source of the oil discharge to the waters of Gore Cove. 41 It is Dr King's opinion that the minimum volume of oil discharged into the waters of Gore Cove, based upon the observation of oil positions and oil behaviour, was a least 123 litres of oil comprising 15 litres of thick black oil in the boomed area and 108 litres outside of the boomed area. The evidence of Dr King in this respect has not been challenged. 42 Dr King calculated that a large globule of oil rising at 0.05m/s through a water column, which is less than 18 metres deep, would take no more than six minutes to reach the surface following a subsurface discharge. The OILMAP computer model was used by Dr King to simulate the influence of currents and winds on Sydney Harbour during the morning of 30 April 2002. Using this information Dr King has expressed an opinion that:- "… the oil which was observed bubbling up to the surface near the stern of the "Frixos", the oil observed already on the water's surface astern of the Frixos, and the oil slick extending out of Gore Cove in a southerly direction towards Balls Head, all originated from a subsurface discharge from the "Frixos" while in Gore Cove". 43 It should be noted that the wind speed and direction data for April 30 2002 was obtained by Dr King from the Bureau of Meteorology sourced from the Bureau's Olympic Park weather station, which is within 12 km of Gore Cove. 44 In a further report dated 11 February 2005, Dr King opined that the thick black oil and heavy sheen oil slick originated from a continuous subsurface discharge from the Frixos as it steamed into Gore Cove and while berthing at the Shell Terminal. In cross examination Dr King agreed that he did not make any direct observations himself and that he relied on the evidence of Mr West and the others. Dr King further agreed in cross examination that he made an assumption in respect of the track or path the Frixos had taken between Sydney Heads and Gore Cove. The defence 45 Mr Byrne has identified a number of gaps in the prosecution's case:- 1) There is no evidence of observation of the waters of Gore Bay between 1630 hours 29 April 2002 and 0800 hours 30 April 2002; a period of 15½ hours. 2) Both of the witnesses Messrs Bennett and Keane respectively swore affidavits on 11 February 2005 and 22 February 2005 almost three years after the event, in the following exactly identical words: "If there had been oil on the waters surface in the area of Gore Bay, around the hull of the "Helix" or on route between Gore Bay and Moores Warehouse, Millers Point, I would have observed it and reported its presence to the SPC". 3) The evidence of Mr Tagoe in an affidavit sworn 23 February 2005 uses identical words to Messrs Bennett and Keane except that the words "around the hull of "Helix" do not appear in his affidavit. 4) In the circumstances the evidence of the three abovementioned witnesses should not be accepted as independent versions of their recollection. 5) There is no evidence of the departure of the Helix from the berth at Gore Bay and the route that it took after it left. 6) There is no evidence of the arrival of the Frixos at the same berth and the route that it took before it arrived. 7) There is no evidence of actual discharge from the Frixos. 8) The prosecution has not proved beyond reasonable doubt that there was not oil on the water that the Frixos passed through where the circumstances are consistent with oil being on the surface of that water. 9) The oily sample taken from the water was by means of the bucket used by Mr Allen within the boomed area. No samples were taken from the heavy sheen oil slick relied upon by Dr King. 10) The absence of evidence of a possible point of discharge, even after divers examined the hull of the Frixos. 11) The absence of an explanation of how the mixture of oils could have occurred either within the Frixos itself or after the oil entered the water. 12) The assumption by Dr King that wind speed and wind direction at Gore Bay would be uniform with wind speed and wind direction at the Olympic site, almost 12km away. 13) The absence of any information in respect of variations in wind speed and direction between the hourly reports relied upon by Dr King. 14) The lack of foundation for the assumption of the path taken by the Frixos made by Dr King. 15) The lack of evidence of any attempt to establish any other potential source besides the Frixos – the initial instruction to Dr Leeder with the first sample was "to determine that the oil in the water is the same as the bilge sample from the vessel." 16) The development of a quantitative linear mixing algorithm by Dr Stout, a theory which possibly explains how the oil in the water might have come from the Frixos without any explanation of how a 70/30 mix could happen. 17) A critical issue in determining a reason for the level of DCTs found in the samples is the method of cleaning the sample jars used. No control jar was delivered to Dr Leeder with the samples. 18) The samples were stored in Dr Leeder's laboratory at ambient temperature for two years before despatch to Dr Tibbetts, although ASTM procedures anticipated they would be refrigerated. 46 I reject the proposition put by Mr Sheahan, namely that the evidence demonstrates that over the period of two days prior to 30 April 2002 when the Frixos was tied up at the berth at Gore Cove, the area of the berth and the waters adjacent to the Shell Oil Terminal were free from oil pollution. Apart from the obvious artificial consistency of the evidence from Messrs Bennett, Keane and Tagoe about the conditions of the water at or about the time of the departure of the Helix, there is simply no evidence that would assist the Court to understand the state of the water around the Shell Oil Terminal and the area between Gore Cove and Balls Head from the time the Helix left until after the Frixos had completed berthing. The circumstantial case 47 In the absence of direct evidence of a discharge from the Frixos the prosecutor must rely on the circumstantial evidence to show that there is no other rational inference consistent with innocence open on the evidence. 48 In summary, the expert evidence does not enable the Court to reach a conclusion beyond reasonable doubt that oil from the Frixos was the source of the spill oil in Gore Bay. 49 Dr Leeder reaches his conclusion with a surprising 100 per cent certainty yet Dr Tibbetts and Dr Stout agree that the singular potential sources of the bilge or the HFO transfer pump oil are "non matches" for the spill. 50 Dr Stout found that the intermediate character of the spill oil warranted development of a linear mixing algorithm, as per the Nordtest methodology, to demonstrate that a mixture of the HFO and the bilge oil candidate source oils produced a positive match. However, Dr Tibbetts has explained that a positive match is not necessarily proof that samples are related. Dr Tibbetts would only go so far as to concede it was probable the Frixos was the source of the spill, although he maintained his doubt regarding the significance of the DCTs. Some lapses in sample analysis procedure have been disclosed relating to the conditions of storage and cleanliness of containers. The actual consequences of these lapses have not been highlighted sufficiently to make a finding about the actual impact, although all the experts seemed to agree that the effect of weathering of the sample could be adequately taken into account. 51 In order to reach a conclusion that the chemical data available provides overwhelming evidence that the Frixos was the source of the spill, Dr Stout made an assumption about the particular type of solvent used on board the Frixos. There is no evidence of what materials containing DCTs were used on the Frixos, if any. 52 Dr King bases his conclusion on a computer generated reconstruction of the conditions in Gore Bay based upon weather, tide and current information. It is not surprising that oil found in Gore Bay itself could be sourced from around the area of the Shell Oil Terminal but the information relied upon by Dr King, particularly in relation to wind direction and strength, is self evidently questionable having regard to the distance between the site and the weather station at Olympic Park almost 12 km away. Dr King also made an assumption unsupported by evidence in respect of the path taken by the Frixos. 53 Each of the four experts has relied on the evidence of lay witnesses to assist them to reach a conclusion. Despite criticism from both sides about the approach taken by the expert witnesses I found Dr Tibbetts and Dr Stout reliable and informative. My impression is that they both approached the task of assisting the Court without any preconceived notion of the outcome. Dr Tibbetts was not able to meet the criteria required to establish the source of the oil spill beyond reasonable doubt and Dr Stout only reached his conclusion after using a theoretical formula to establish a possible mix of oils. 54 However none of the expert witnesses were briefed to consider any alternative sources for the spill and did not do so. They were requested in each case to use their expertise to address the connection with only one potential source, namely the Frixos. 55 Not one witness was able to give evidence of an emission of oil from the hull of the Frixos into the water. There is no explanation of how a discharge might have occurred and more particularly how a mix representing the oils in the samples taken from the ship was possible. Divers were able to confirm the presence of oil on the hull of the ship which was easily dislodged but made no observation identifying a particular point of discharge from the interior of the vessel 56 The spill oil was variously described as containing degraded bunker fuel oil, lubricating oil, fresh heavy fuel oil blended with a kerosene-based cutter and biodegraded crude or heavy fuel oil. 57 There is simply no evidence of any investigation of any other potential source such as other ships in the area during the relevant period including the Helix and even for example the SPC boats attending the Frixos. 58 The evidence certainly disclosed that there was oil on the waters of Gore Bay and there was a probability that the source of the oil could have been the Frixos. However, I am not convinced that the prosecution has proved that fact beyond reasonable doubt particularly having regard firstly to the conflicting opinions of the experts and secondly the resort to a mathematical theory by Dr Stout to establish the prospect of a mixture. 59 The lack of any explanation for a possible mixture either within the Frixos or after discharge leaves the theory demonstrated by Dr Stout no more than that, namely a theory. 60 The evidence does not eliminate the prospect of a discharge from another vessel in the area of what is an overseas oil terminal where I can assume regular deliveries by other ships such as the Frixos and the Helix take place. The gap of 15½ hours between the departure of the Helix and the arrival of the Frixos obviously provided adequate time during which other vessels could have entered and left the area. The Court has no information in relation to other general harbour traffic during this time. The prospect of the Frixos travelling through an existing oil slick on the waters of Gore Bay or elsewhere has not been adequately addressed by the evidence, let alone eliminated. 61 In order to prove a case by circumstantial evidence the evidentiary circumstances must bear no other reasonable explanation (Martin v Osborne (1936) 55 CLR 367 at 375 per Dixon J, noted with approval by the majority in Knight v The Queen 175 CLR 495 at 502 and 503). I am not able to conclude in this case that the degree of probability that the discharge of oil took place from the Frixos is so high that the contrary cannot reasonably be supposed. The prosecution case is directed solely to showing that the Frixos was the source of the spill. That in itself has not been proved to my satisfaction beyond reasonable doubt. Furthermore, as the prospect of a discharge from another ship or of the Frixos travelling through an existing slick has not been negatived and the means of a mixture occurring has not been explained, then the defendants should be given the benefit of the doubt. Costs 62 The defendants as the successful parties are entitled to an order for the payment of their costs by the prosecution (Latoudis v Casey (1990) 170 CLR 534). Orders 1. I find each of the defendants in Matters No. 50051 of 2004 and 50052 of 2004 not guilty. 2. The summons in each case is dismissed. 3. The Prosecutor is ordered to pay each of the defendant's costs. 4. The exhibits may be returned. DISCLAIMER - Every effort has been made to comply with suppression orders or statutory provisions prohibiting publication that may apply to this judgment or decision. The onus remains on any person using material in the judgment or decision to ensure that the intended use of that material does not breach any such order or provision. Further enquiries may be directed to the Registry of the Court or Tribunal in which it was generated.