With safer alternatives in use, why do some companies insist on employing a wall-wash test?
The wall-wash test (WWT) remains a standard requirement in many chartering instructions, despite growing evidence that it serves more as a commercial ritual than a reliable measure of tank cleanliness. While operators such as MOL Chemical Tankers have adopted washing-water analysis to reduce risk and improve cleaning transparency, others continue to mandate procedures that expose crews to unnecessary danger. At the heart of the issue lies a deeper question: are some in the industry simply washing their hands of responsibility by outsourcing liability to shipowners and crew?
WWT involves entering enclosed spaces and manually applying solvents to a section of the tank wall to collect samples for laboratory analysis. It is inherently hazardous. “Confined space entry remains the single most dangerous operation on a chemical tanker,” said owner of L&I Maritime and partner at Spectrovise, Guy Johnson. “There is no training, equipment or process that makes going into an enclosed space completely safe, especially with flammable and toxic solvents involved.”
“If this is not self-certification, I do not know what is”
His concerns, posted on LinkedIn in response to a methanol wall-wash test ahead of an Annex I cargo, sparked a wider discussion across the industry. Surveyors had been instructed not to enter the tank; instead, crew were asked to perform the sampling. “If this is not self-certification, I do not know what is,” Mr Johnson wrote. “Why can the vessel not certify the tank by whatever means available to them, instead of maintaining a charade?”
The frustration was widely shared. “We need to start lobbying the industry to ban wall washing for commercial gains,” Mr Johnson added in a follow-up. “There is no guarantee the wall wash provides anything meaningful, and we are putting human lives at risk for a test that does not include cargo lines and cannot provide full assurance.”
MOL Chemical Tankers, a vocal advocate for reform, has implemented washing-water analysis across its fleet. “Washing-water analysis allows us to sample live during cleaning and assess residue levels in real time,” said MOL Chemical Tankers general manager, operations optimization, Dorte Aaskoven Creaven. “Once we see that the last seawater sample contains less than 100 ppm of the previous cargo, we proceed to rinse, gas-free and visually inspect the tanks. That means just one confined space entry per tank, if needed.”
The company’s experience over more than a decade has demonstrated that tanks prepared this way meet cargo specifications consistently. “Our officers know the vessel and the tank-cleaning process better than anyone,” Ms Creaven said. “They monitor each stage, follow the cleaning guidance, take live samples and make informed decisions. The idea that they need to be second-guessed by a test that is both random and narrow in scope is outdated.”
Washing-water analysis also incorporates the tank’s cargo lines — something the WWT ignores. “We are covering 100% of the system rather than a single patch of steel,” said Ms Creaven. “And we are documenting the entire process. It is not subjective. It is transparent.”
The environmental and commercial advantages are also substantial. “Each hour of hot-water washing equals around 1.9 metric tonnes of CO2,” she added. “By avoiding overcleaning, we reduce emissions, save fuel and arrive at terminals faster. Charterers benefit from shorter port stays, no waiting for surveyors, and better berth rotation.”
Some charterers have accepted the method. “Fortunately, a number of our customers now see the benefits,” said Ms Creaven. “They receive the full data package before the vessel arrives. The tanks are clean, inerted if necessary, and ready for first foot loading. There is no waiting and no cost to them.”
MOL Chemical Tankers was the recipient of the 2023 Chemical & Product Tanker Commitment to Excellence Award, in part for the work it has done in eliminating WWT.
Despite this progress by one of the leading lights in the chemical tanker industry, many others continue to insist on WWT. “After successful meetings and agreement on principle, the very next fixture often reverts to requiring a wall wash,” Mr Johnson noted. “It is a frustrating cycle, and it suggests the issue is not technical — it is cultural and commercial.”
Uniservice Unisafe sales manager, Tony Walton, offerd a commercial perspective on the resistance to change. “At industry events, the public message is always about safety, innovation, and environmental performance,” he said. “But that rhetoric collapses at the operational level. Historic procedures are still dominant, and new ideas, even when demonstrably better, are treated with suspicion.”
Uniservice has promoted washing-water analysis and lower-temperature detergents as part of its sustainability efforts. “We developed new cleaning agents that reduce energy consumption and emissions,” Mr Walton said. “We also support the shift away from wall-wash testing. It is safer and it aligns with what the industry claims to believe in.”
Yet change is slow. “There is a deep-seated inertia onboard,” said Mr Walton. “The phrase we hear most often is: ‘If it ain’t broke, don’t fix it.’ But it is broken. We are ignoring safer, more efficient methods because they are unfamiliar. Worse, some charterers are demanding conditions that have no scientific foundation.”
He described a recent case where a client declined proposed process improvements — even after they were shown potential gains in safety and cost. “They just said they were uncomfortable changing procedures. It was not about evidence. It was about fear of doing something different.”
Mr Walton believes this resistance stems from a combination of outdated power dynamics and a lack of enforcement. “In many cases, charterers are dictating standards that offer no real benefit and increase risk. The ship has little choice but to comply, even when the crew knows it is counterproductive.”
He also sees parallels with other sectors. “In banking, where I worked previously, risk and compliance culture is far more developed. In maritime, the approach is often reactive — change only happens when there is a serious incident or new regulation.”
According to Mr Walton, more rigorous oversight could close the gap. “If we want better outcomes, we need to measure and report the tank cleaning process. How long did it take? What was the fuel consumption? What was the readiness standard? That level of transparency would drive change.”
Mr Johnson, meanwhile, calls on industry organisations to take a firmer stance. “These bodies need to advocate for a ban on wall washing for commercial gain. There is no benefit. It is unsafe, ineffective and inconsistent with our wider goals.”
He questions why major charterers accept such practices, when their own policies would not allow them to instruct their own people to enter a confined space, with a bottle of methanol to take a sample with no control over the medium or the process. “So why are we asking our officers to do it?” he asked.
Commentary on Mr Johnson’s LinkedIn post suggested there one element in the commercial chain that has to take some responsibility for the persistence of WWT. Some commenters pointed to the role of insurers in maintaining the status quo, and the reluctance to engage in change or recognition of the problem.
The sentiment is clear. While technical alternatives exist and are in use, entrenched behaviours and liability avoidance are holding the industry back. “We talk about safety, but we do not always act on it,” said Ms Creaven. “This is an area where we can act — today. There is nothing stopping us from doing the right thing.”
For those shaping the future of chemical tanker operations, the message is becoming increasingly difficult to ignore. “We need to align our policies with our principles,” said Mr Walton. “That means putting safety ahead of habit, and science ahead of superstition.”
As Mr Johnson concluded: “We know what works. We know what is safe. The wall-wash test belongs in the past. It is time we stopped pretending otherwise.”
