Coconut oil might not seem risky at first glance, but transporting it can release toxic gases and reduce oxygen levels in confined spaces. Manish Nayyar, a Senior Loss Prevention Executive at NorthStandard, highlights t...
Coconut oil might not seem risky at first glance, but transporting it can release toxic gases and reduce oxygen levels in confined spaces. Manish Nayyar, a Senior Loss Prevention Executive at NorthStandard, highlights the need for crew members working inside cargo tanks to be well-informed.
Shipping coconut oil and its byproducts, including Crude Coconut Oil (CCNO), Coconut Oil Fatty Acid Distillate (CFAD), and Refined Coconut Oil, poses a significant and often overlooked risk: the generation of harmful gas in the ship’s cargo tanks.
Unlike what many believe, vegetable oils, especially crude coconut oil (CCNO), can lead to serious atmospheric dangers in enclosed areas. CCNO, with its higher impurity and lower thermal stability than refined coconut oil, can emit carbon monoxide (CO) – a colorless, odorless, and potentially deadly gas – when heated or disturbed.
Likewise, CFAD has medium-chain fatty acids like capric acid (C10) and lauric acid (C12), which can vaporize when heated or agitated. This could create flammable vapor-air mixtures, reduce oxygen levels, and cause skin and eye irritation.
Both of these risks can lead to suffocation and are hard to identify without sensors. Even if gas detectors are used, it doesn’t guarantee ongoing safety throughout the operation. Movements like circulation, heating, or stripping of the cargo can release trapped gases, quickly changing a "safe" tank atmosphere into a hazardous one.
The risk is real
Two recent incidents have served as a wake-up call for the tanker industry. In the first case, two crew members entered a cargo oil tank during a routine CCNO discharge in Rotterdam.
Even though pre-entry tests showed safe levels (20.9% oxygen and nearly zero CO or hydrogen sulfide), cargo circulation caused visible vapors near the bell mouth. The pumpman's gas detector alarm went off, but he lost consciousness before evacuating the tank, leading to both crew members being hospitalized. Follow-up testing showed CO levels in the tank reached a shocking 400ppm.
In the second incident, during a CFAD discharge in Lianyungang, China, five crew members entered a cargo tank without proper atmospheric testing or following necessary entry procedures. All five collapsed due to toxic gas exposure, and tragically, four of them died.
Incident analysis
Looking back, these accidents were predictable due to repeated procedural mishaps. The ship's staff didn’t identify the release of dangerous vapors during cargo handling, and the pre-entry assessments were insufficient. Both events were worsened by communication failures; for example, the Cargo Control Room (CCR) was unaware that personnel were still inside the tank.
The cases also highlighted the crew’s limited knowledge about the toxic vapors associated with coconut oil products, the effects of cargo movement on the tank atmosphere, and the fact that initial "safe" readings do not guarantee ongoing safety.
Moreover, personal gas detectors can only alert users at advanced danger levels. In the CCNO incident in Rotterdam, a single portable ventilation unit was insufficient for a large cargo tank.
Tank entry preparation
Given this knowledge, it is essential for the tanker industry to implement steps to prevent similar incidents.
A key safety measure is prohibiting any cargo movement while personnel are inside the cargo tanks, unless an authorized and documented risk assessment is completed. This rule was ignored in the first incident at Rotterdam, directly contributing to the tragedy.
Other significant checks and procedures must also be in place. Before entering, crew members should perform thorough multi-point testing at the top, middle, and bottom of the tank, from various access points like manholes and butterworth openings. For vegetable oils, at least four hours should be allocated for ventilation, and oxygen levels must be confirmed to be at or above 20.9%, with toxic gases (including CO) at 0ppm.
After entry, crew members inside the tank must regularly monitor the atmosphere every 15 minutes, using extended sampling tubes to assess conditions at multiple levels and set conservative alarm thresholds (e.g., oxygen dropping below 20.5% or CO rising above 25ppm).
Ventilation and communication
Large cargo tanks carrying coconut oil products need multiple ventilation points; relying on a single portable blower is insufficient. The crew must ensure the tank remains well-ventilated throughout the entry period, addressing any areas of poor air circulation.
Communication protocols should be improved. The CCR should have a closed-loop system and secure clear confirmation of “all personnel clear” before any cargo operations begin. While personnel are inside the tank, radio checks should occur every 10-15 minutes with pre-agreed codewords for immediate evacuation, and all communications should be documented by the CCR officer.
Significant defenses
Lastly, managing temperatures is vital for safe operations when dealing with coconut oil products. Heating temperatures in cargo tanks should be kept at necessary minimum levels to maintain fluidity while avoiding hazards, particularly preventing rapid temperature changes.
The risks increase during cleaning and squeezing operations because heating residues to facilitate their removal can release trapped gases, and any bottom residues may contain concentrated impurities that heighten the chances of hazardous atmospheric changes.
Overall, these measures should not be considered optional, but rather essential defenses against crew illness, injury, and fatalities.