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Contaminated bunkers: ‘The Houston Problem’

Clyde & Co offers several pointers to help shipowners protect themselves against problematic fuels.

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International law firm Clyde & Co recently offered advice to shipowners on how the group can better protect themselves from contaminated bunkers: 

The shipping industry has seen a significant number of bunker quality related engine problems during 2018. In this Note we consider the key legal issues likely to arise.

The problem started with fuel supplied in the US Gulf region, particularly in the Houston area, but the problems quickly spread to Panama.  More recently, similar problems have been encountered with fuel supplies out of Singapore.[1]  So although the problem is now widespread, it is described in the industry as "the Houston problem", Houston being the first location affected.  Industry commentators estimate that in excess of 200 vessels have been affected by quality related issues following supplies of bunkers.  

By late August, Fobas alone have confirmed that they are involved in 60 cases, of which 30 stemmed from supplies in Houston, 15 in Panama, and 5 in Singapore. 

It is widely expected that the problem will continue to grow.

The common problem arising out of the burning of the fuel involves the sticking and seizure of fuel-injection system components and the blocking of fuel filters.  In many cases the damage to the engine and the cost of repair is modest. 

In other cases the impact is far more dramatic.  Press reports have identified a number of ships, which suffered black outs and groundings, allegedly as a result of bad bunkers. 

The evidence, coming to light, suggests that the problem arises from the inclusion of adulterants and contaminants within the fuel of non-petroleum refining origin. 

Two different forms of contaminants appear common:  some bad fuels show evidence of chemical waste related to bisphenol manufacturing operations, whilst others show evidence of bio-derived contaminants, including tall oil – a by-product from the timber industry.

Why is this such a major problem for ship owners?

The overwhelming majority of bunkers are supplied under contracts, which stipulate that they will comply with the ISO 8217 parameters.  Supplies are frequently tested immediately after delivery to ensure that the fuel complies with the "Table 2" test requirements within IS0 8217,[2] which tests for water content, aluminium, sulphur, etc.  The vast majority of the Houston Problem supplies are on specification for Table 2 parameters.
This has led to vessels consuming the fuel and only when engine damage occurs is the potential problem discovered.

The contaminants found in the Houston Problem bunkers can only be identified by advanced analytical techniques such as gas chromatography, combined with mass spectrometry (GC-MS), which go beyond the standard tests for Table 2 parameters.  Few laboratories in the world have the ability to perform GC-MS testing and this has caused a major backlog in the delivery of results.  Few GC-MS tests were carried out at the time the problem began although this is changing.

What should an owner do to ensure the safety of his ship?

The industry is now alive to the Houston Problem and prudent owners are insisting upon testing involving GC-MS techniques before fuels can be consumed.  This remains the only safe way of ensuring the fuel will not have characteristics consistent with the Houston Problem.

If an owner, unfortunately, encounters bad fuel with the Houston characteristics then, depending on the extent of the contamination, it is likely that this fuel cannot be safely consumed and must be de-bunkered (although some vessels have consumed the fuel safely). 

The issue facing owners when suffering the Houston Problem is who is contractually obliged to de-bunker the vessel (with associated loss of time) and/or to compensate an owner for the consequences of burning the bad fuel. 

Position under charter parties

Where owners have chartered the vessel by way of a time-charter party, then the charterer is contractually obliged to supply fuel to the vessel and, in the absence of any special conditions, it is implied that such fuel will be fit for consumption by a reasonably well maintained vessel.  

Fuel displaying the characteristics of Houston bunkers is likely to be in breach of this obligation.

Further, many Time Charters impose obligations on the Time Charterers to supply fuel compliant with ISO 8217.

The start point when looking at whether the fuel is compliant with ISO 8217 is Clause 5 setting out the general requirements.  Clause 5.1 requires the fuel to confirm to the characteristics and limits set out in Table 2. 

However, the remainder of Clause 5[3] requires the fuel to be:

  • "A homogenous blend of hydro-carbons derived from petroleum refining".
  • "Free of inorganic acids and used lubricating oil".
  • "Free of any material that renders a fuel unacceptable for use in marine applications".
  • "Shall not contain any additive at the concentration used in the fuel or any added substance of chemical waste that jeopardises the safety of the ship or adversely affects the performance of the machinery".

If the result of the GC-MS testing is to identify chemical waste relating to the bisphenol manufacturing or bio derived contaminants (i.e. the Houston Problem) then it is likely that the fuel is in breach of some or all of the above Clause 5 obligations.

The immediate recourse action for any ship owner fearing or actually suffering engine damage through bad bunkers, is to pass liability to the Charterers and call upon them to de-bunker the vessel and compensate owners for such losses.

Where the owners themselves have purchased the fuel, the position is more complex.

Bunker supply contracts

The supply of bunkers is, in the absence of a bespoke contract, usually done on the physical supplier's or trader's terms and conditions of business.  They are inevitably weighted in favour of the seller.  These supply contracts invariably contain the following provisions:

  • Short periods of time for notification of a quality claim. These range from as short as 7 days up to 28 days but rarely, in the absence of any bespoke agreement, any longer. Given that in many cases the innocent buyer of the fuel will have no knowledge of the problem until the fuel is consumed (and quite often not until a large quantity is consumed weeks later), then many buyers are facing the problem of not knowing that they have a claim until after the notification period has expired. The enforceability, or otherwise, of these short time limits is the subject of current debate and, we anticipate, will inevitably be determined by the Courts in the near future. The start point though is that notification of a claim outside the time limit may result in the claim being waived i.e. lost in its entirety.
  • Clear requirements for only the Bunker Delivery Note samples to have any evidential value and so any ship samples will be disregarded for establishing the quality of the fuel.
  • A waiver of all claims if the vessel co-mingles the fuel or fails to permit the Seller's survey and access or fails to preserve any damaged parts.
  • Most bunker contracts contain caps on liability, whereby the seller can limit liability to the purchase price or less. They frequently contain exclusions of liability for consequential losses, loss of hire, loss of use, etc, and limit any recourse solely to physical damage. Many terms also will only pay a portion of the engine damage cost, applying depreciation calculations to limit liability still further. It is unlikely an Owner would recover his losses in full because of these limitation provisions.

How can owners protect themselves?

The key to protecting the interest of the owners and their insurers is to take prudent steps to test fuel stemmed out of the Houston area or Singapore, including GC-MS testing before use.  Where this is not possible, extreme care should be taken when consuming the fuel and regular checks on engine performance should be undertaken to monitor performance. 

Where the test results show the presence of contaminants consistent with the Houston Problem, then the fuel should not be consumed if at all possible and the Seller or Charterer should be put on immediate notice.  If there is any doubt as to the quality of the fuel, an early notice within the time limit of the trader/supplier's terms and conditions is prudent whether such notice would comply with the express terms of the supply contract, which usually requires a fully documented claim. 

An early dialogue should be initiated with the seller to prove the off-spec nature of the fuel and the damage, and to compel a prompt de-bunkering.

It is hoped that now the Houston Problem is well known that the contaminants will be removed from the supply chain.  Only time will tell whether this problem will continue.


[1] Singapore imports approximately 40% of its bunkers from the US.
[2] Table 1 deals with distillate fuels whilst Table 2 deals with residual marine fuels.
[3] The wording varies according to which version of ISO 8217 is adopted.

The above article is written by the following authors:
Andrew Preston, Partner
T: +44 (0) 20 7876 4740
M: +44 7971 276 540
E: [email protected]

Mike Roderick, Partner
T: +44 (0) 20 7876 4534
M: +44 7739 788 187
E: [email protected]

Published: 17 September, 2018

 

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Bunker Fuel

Alkagesta highlights key insights on European choke point pressures in August

Update covers dual supply crisis currently shaping global bunker markets — a stalled Strait of Hormuz peace process and Rhine water levels at a 140-year record low — and the implications for Singapore.

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Malta-based global commodity trading house Alkagesta recently shared latest market insight examining the dual supply crisis gripping global energy markets as diplomatic efforts to reopen the Strait of Hormuz stall and Rhine water levels fall to record lows, creating what the company describes as a “state of emergency” for European inland fuel distribution.

In an article published on Alkagesta Market Insights on 11 August, the company’s trading and market intelligence teams outlined how the convergence of two simultaneous logistical crises is tightening prompt fuel availability across Singapore, Northwest Europe, and the Mediterranean:

Strait of Hormuz transits fell to a near-one-month low of 13 ships on August 9 following an attack on an ADNOC-linked tanker, as both the US and Iran demand war reparations before any reopening agreement can be reached. Simultaneously, Rhine water levels at the Kaub chokepoint fell to 16 cm on August 10 — the lowest since records began in 1880 — with forecasts pointing to a further drop to just 4 cm by August 14, effectively halting barge traffic and trapping fuel oil stocks at the ARA hub.

The supply picture across both key hubs has deteriorated sharply. In Singapore, Middle Eastern fuel oil imports nearly tripled week-over-week to 328,878 mt by July 29 — the highest volume since March — providing some relief as onshore commercial heavy distillate stocks rose to a five-week high of 19.58 million barrels by August 5. However, July bunker fuel sales are estimated to have fallen 3.7% month-over-month to 4.44 million mt, with elevated premiums redirecting prompt demand toward alternative ports including Zhoushan and Port Klang.

In Europe, the VLSFO market remains acutely undersupplied as refiners continue to prioritize high-margin diesel over low-sulfur blending components, while the Rhine crisis has forced barges to operate at just 15–20% of normal capacity — with freight rates from Rotterdam to Karlsruhe rising more than 400% in two months.

Alkagesta’s strategic outlook points to a potential total breakdown in Rhine-linked inland distribution by mid-August, a VLSFO Hi-5 spread likely to remain above $200/mt through Q3, and a global crude market that analysts warn requires an additional 2.1 million b/d for 18 months to rebuild depleted inventories.

Note: The full article can be read here.

 

Photo credit: Alkagesta
Published: 17 August, 2026

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Bunker Fuel

Integr8 Fuels: Why bunker markets could be lower than we thought

Marine fuel prices could prove lower than previously anticipated as easing refinery margins and improving bunker market fundamentals outweigh a still-uncertain crude oil outlook, says Integr8 Fuels.

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By Steve Christy, Expert Contributor, Integr8 Fuels

29 July 2026

We have just seen one false dawn, is there another to come? 

Last month, we wrote about how close we were to the expected lows in Brent and Rotterdam bunker prices, but not yet Singapore. Given what has happened since, a month is not only a long time in politics, but also a very long time in the bunker market. 

There was a resumption of attacks in the Arabian Gulf region on 13 July, followed by targeted Houthi attacks on Saudi Arabia’s Red Sea oil infrastructure and shipping in the Bab el-Mandeb region, the gateway between the Red Sea and the Gulf of Aden. As a result, Brent futures fell to lows of around $70/bbl in late June and early July before surging to a high of $100/bbl on 23 July. Over the same period, Singapore VLSFO fell to $635/mt before climbing to $865/mt, a swing of $230/mt in just 16 days. 

Jul 2026 Graph 01 1024x613 1

Prices at the start of this week fell sharply after a halt in Arabian Gulf attacks over the weekend, with front month Brent was down to intra-day lows of $84/bbl, and Singapore VLSFO $750/mt.  However, at the time of writing there has been a ‘surprise’ attack by Iran, and retaliatory action by the US, with prices rising again.  It looks like we could be at another false dawn. 

The obvious questions are: will there be a return to peace negotiations, and are we close to the end of the war and free-flowing traffic through the strait of Hormuz (and also the Bab el-Mandeb)? The obvious answer is, we don’t know; there are only a few people that are likely to know the answer to this. All we can do is plan for every eventuality. 

Low stocks, higher bunker prices, and a strong Singapore VLSFO premium: it’s a challenge 

For those of us in the bunker market, the point we made last month about Singapore VLSFO trading at a strong premium to crude still holds, albeit slightly less pronounced. The loss of supplies through the Strait of Hormuz, together with the added uncertainty surrounding Saudi product exports from the Jizan and Rabigh refineries on the Red Sea, has sustained this premium. 

These developments are likely to keep the Singapore VLSFO premium to crude at elevated levels until there is greater confidence that Middle East crude and product supplies are returning to more normal trading patterns. Amid all the price volatility, this Singapore VLSFO premium remains a key indicator to watch. 

Backwardation in Brent futures illustrates market psychology 

One month ago, backwardation in Brent futures (front month minus second month) had fallen from $7/bbl to virtually nothing, reflecting the market’s belief that an end to the war was little more than a negotiating step away. It wasn’t. The resumption of attacks, coupled with Houthi involvement in the Red Sea, sent prices sharply higher again, with backwardation in the Brent futures market returning to almost $6/bbl. 

Jul 2026 Graph 02 1024x572 1

The halt in attacks over the past weekend has taken steam out of the market, with prices and backwardation falling sharply. Where we go from here depends if there is again a belief peace is on the horizon, or if this is another false dawn. The past month highlights how impossible it is to predict an ending to the war, and how fragile any expectations of peace can be. 

We cannot ignore the price, but still must look to the future

It is impossible to write a report and not highlight the turmoil of the current market and what is happening. However, we still must look beyond this, to see where we could end up. 

In an earlier report, we suggested the run-up to the US mid-term elections in November may be a backstop to the war. However, even this is not guaranteed. There are many dynamic elements to the economy and voter intentions, but one feature that will always crop up in the US is the gasoline price. This has risen from $3/gallon before the war to over $4/gallon for the past four months. 

Jul 2026 Graph 03 1024x570 1

If it comes to it, will Republican voters want to see a resolution to the war and a return to $3 gasoline prices ahead of the elections? 

We have a change of heart on how low bunker prices can go

We don’t know exact timings, but in any planning, we must look at what happens when the war does finally end and prices fall, whenever that may be. In past reports we have highlighted the view that Brent crude prices are unlikely to fall back to pre-war levels in the $60s, and Singapore VLSFO unlikely to go back in to the $400s. This may be the point at which these views change.

Previous thinking was based on a relatively short war, where there would be a large loss of oil supply and a massive stock-draw. In this case, tighter stock levels would be sufficient to keep prices higher than their pre-war levels once we returned to ‘normality’. This would mean Brent futures in the $70s (and not in the $60s), and Singapore VLSFO in the $500s, and not the $400s.

A number of mainstream analysts also held this view, although there were some that were lower and some higher.

Given the war has already gone on for much longer than almost everyone expected, this thinking must change. Yes, global stocks have been drawn down at a rapid rate, but this is slowing. Higher pricing and inflationary blows have had a major impact on global oil demand, with current indications that total oil demand in the second quarter of this year was some 4 million b/d lower than year earlier levels.

The graph below shows this sharp drop in demand and even if the war comes to an end relatively soon, and demand gets back towards some normality, a structural loss of more than 1 million b/d in global oil demand is still expected to have taken place because of the extended period of conflict.

If the war goes on for even longer, structural losses in global oil demand are likely to be even greater.

Jul 2026 Graph 04 1024x579 1

Source: US EIA

It’s a hard road, but we can get there

This means that once the war does end, market psychology will be looking at a rapid increase in oil supplies going into a global market which is much lower in demand.  This opens the way for prices to easily return to their pre-war levels of Brent in the $60s and Singapore VLSFO in the $400s. 

Now we just need those at the centre of negotiations to get us there.

 

Photo credit and source: Integr8 Fuels
Published: 30 July, 2026

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Bunker Fuel Quality

FOBAS report warns of growing operational risks from ISO-compliant bunker fuels

LR’s latest FOBAS Fuel Quality Report reveals that the biggest fuel quality risks are no longer confined to off-specification fuels, with some compliant fuels creating operational challenges.

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New FOBAS report warns growing operational risks from ISO-compliant bunker fuels

Classification society Lloyd’s Register (LR) on Tuesday (14 July) warned that ship operators are facing a growing risk from fuels that appear compliant under routine ISO 8217 testing but still present operational risks once onboard.

According to LR’s latest Fuel Oil Bunker Analysis and Advisory Service (FOBAS) Fuel Quality Report, covering the first half of 2026, off-specification fuels remain a persistent challenge. 

However, some of the most disruptive cases now involve fuels that pass routine compliance testing but show poor stability or compatibility, or contain non-conventional blend components that are only identified through more detailed investigative analysis.

Several incidents investigated highlighted this trend. In March and April, a number of vessels reported operational difficulties after bunkering fuel in a major bunkering hub. Further forensic analysis found that many of the fuels contained elevated concentrations of Estonian shale oil, in some cases estimated to be around 10-15%.

While shale oil is recognised within ISO 8217 as an acceptable blend component, FOBAS investigations found that higher concentrations can be associated with fuel instability and operational issues affecting filters, separators and fuel pumps.

The report also shows that fuel quality variability remains stubbornly high. Off-specification cases remained elevated throughout the first six months of 2026, suggesting that quality issues are no longer isolated events but a more persistent feature of today’s marine fuel supply chain.

The most common recurring issues included sulphur exceedances, excessive water content, sediment and stability problems, elevated catalytic fines, sodium contamination and low flash point distillate fuels.

At the same time, biofuels (especially FAME blends) are continuing to grow without being a primary source of quality issues. Where issues occurred in blended fuels, they were generally associated with the conventional VLSFO component rather than the FAME fraction.

The report concluded that operators will need to adopt a more proactive approach to fuel management as marine fuels become more diverse and fuel quality risks become harder to identify through routine compliance testing alone.

Greater emphasis on fuel stability, compatibility and understanding fuel composition will be critical to reducing operational disruption and maintaining vessel performance.

Murray Kirkwood, Fuel Specialist Consultant, Lloyd’s Register, said: “The findings from our latest report show that fuel quality risk is evolving. The challenge is no longer simply identifying fuels that fail specification. Increasingly, operators are encountering fuels that meet the required limits but still create operational difficulties once they are stored, handled and used onboard.

“As fuel blending becomes more complex, the distinction that matters is increasingly not between on-spec and off-spec fuel, but between fuels that are operationally resilient and fuels that are operationally fragile. Understanding that difference is becoming essential for shipowners and operators.”

The latest findings reinforced FOBAS’ long-standing view that effective fuel management increasingly depends on understanding fuel behaviour rather than relying solely on pass-or-fail specification testing.

By combining routine fuel quality monitoring with forensic investigation of operational incidents, FOBAS provides shipowners with a clearer understanding of emerging fuel quality risks as the industry continues its transition to a more diverse and complex fuel landscape.

Note: The FOBAS Fuel Insight: Fuel Quality Report H1 2026 is available at FOBAS Fuel Insight: Fuel quality reports | LR

 

Photo credit: Lloyd’s Register
Published: 15 July, 2026

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