What Is Cargo Fumigation?
Fumigation is the controlled release of toxic gases (pesticides) in a confined space – such as a cargo hold or container – to eliminate living insects or other pests that could damage the cargo. This method is widely used in international trade to preserve cargo quality and prevent the spread of invasive species.
Why Is Fumigation Necessary?
Pests like beetles, termites, rats, and even birds can cause serious damage to goods, crops, and packaging materials. Beyond economic losses, they also pose health risks by transmitting diseases. Globally, pest-related damage leads to billions of dollars in losses every year.
Fumigation is often mandatory under import and export regulations to stop the spread of invasive species and quarantine pests.
For practical and economic reasons, fumigation is frequently carried out during transportation.
Phosphine: Properties, Applications, and Risks
The most commonly used gas for in-transit fumigation is phosphine. Methyl bromide is banned in most countries due to its harmful effects on the ozone layer and is not permitted for bulk cargo fumigation anyhow. Its replacement, sulfuryl fluoride, must not be used for in-transit bulk cargo fumigation.
Properties
Phosphine (PH₃) is a colorless, flammable, and highly toxic gas. Although it may emit a garlic or rotten fish smell, pure phosphine is odourless – making it especially dangerous. Heavier than air, it accumulates in low-lying spaces.
Application
Phosphine is generated from aluminum phosphide tablets, which react with ambient moisture to gradually release the gas. Common application methods include:
- Spreading tablets on top of the cargo
- Inserting them via slits or probes
- Using sleeves
Human Health Risks
Even at very low concentrations, inhaling phosphine can cause severe health effects, ranging from headaches and respiratory issues to organ failure and death. There is no antidote. Emergency treatment consists of immediately removing the victim from exposure and providing supportive care – always using protective equipment.
As long as the tablets have not fully decomposed, they continue to emit toxic gas. Before unloading, the cargo must be ventilated and can only be released following professional gas measurement.
Most fatal incidents could have been avoided with basic knowledge of the dangers of phosphine.
Fire and Explosion Hazards
Phosphine is pyrophoric: under certain conditions, it can ignite spontaneously upon contact with air. Additionally, the reaction that produces phosphine gas from aluminum phosphide is exothermic. There have been several explosions in ship holds, often causing structural damage to hatch covers.
Key preventive measures include:
- Avoiding moist cargo
- Ensuring tablets are dispersed evenly, not in large heaps
- Correct dosing
- Properly sealing hatches
- Eliminating ignition sources
Legal Framework and IMO Recommendations
The International Maritime Organization (IMO) has issued guidelines for the safe use of pesticides onboard vessels.
Key requirements include:
- Fumigation may only occur with approval from the competent authorities and the ship’s command
- Application, removal, and gas clearance must be performed by an external certified fumigator
- The ship must carry adequate safety equipment
- A minimum of two trained crew members is required
- Inspections for gas leaks before and after loading
- Regular gas measurements during the voyage
Alternative Treatments
There are alternative methods to phosphine that carry fewer inherent risks, although they are not always feasible:
- Temperature treatments: Used mainly on wood; extreme heat or cold kills all life stages
- Controlled atmospheres: Replacing oxygen with nitrogen or carbon dioxide. This is more difficult and costly, and less effective against eggs and larvae.
Conclusion
Fumigating goods is essential to protect food resources and prevent the global spread of invasive species. For practical and economic reasons, it is often carried out during transport.
However, if not applied and monitored with the necessary expertise and care, fumigation poses serious poisoning and explosion risks.
By complying with international regulations and engaging professional fumigators, the owners, charterers, and captains can ensure that cargo is treated safely, effectively, and in compliance with standards.
Want to learn more about fumigation and maritime risks?
Contact the specialists at Van Ameyde Marine
