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3.3 Ship board fumigation


3.3.1. Fumigation at anchor or intransit (with crew on board)
3.3.2. Ship fumigation while ship is evacuated by personnel and crew
3.3.3. Ship board fumigation using phosphine
3.3.4. Application after loading bulk maize without prior installation of tubing
3.3.5. Fumigation of shipping containers
3.3.6. Ship inspection
3.3.7. Fumigation of enclosed metal truck and rail trailers


Fumigation of grain on hoard a ship may sometimes he necessary because of previous infestation in poorly cleaned holds hut is more often required due to an undetected infestation in grain that is being loaded.

Fumigations can be done either on the berth, at anchor, or intransit. The high cost of demurrage when ships are held at anchor or on the berth makes intransit fumigation an attractive option, hut there are safety problems.

3.3.1. Fumigation at anchor or intransit (with crew on board)


3.3.1.1. Suitability of vessels:
3.3.1.2. Testing for leakage
3.3.1.3. Key safety requirements in ship board fumigation (see IMO guidelines)


Small leaks of gas can contaminate crews quarters, paint lockers and other areas and have resulted in previous injuries and deaths. Intransit fumigation should only he done if a competent person has examined and tested the ship and certified that a fumigation can be undertaken without undue risk. Unless a proven hatch test has taken place a trained person then must accompany the ship and take gas readings throughout the fumigation so that any leakage will be discovered and appropriate actions can he taken.

Fumigation of bulk grain in ship's holds is often ineffective because it is difficult to get even and sufficiently deep penetration of the gas. It is almost impossible to get good penetration of bulk grain with methyl bromide without a re-circulation system and penetration with phosphine can taken anything from 8-15 days or more, depending on the depth of the hold. In some tests conducted by the United States Department of Agriculture (USDA) adequate gas penetration was never achieved in the bottom of holds, unless ducts were installed prior to loading.

Fumigation of ships prior to export or intransit is a valuable technique, since the possibility of re-infestation (or cross infestation) from later sources of contamination is largely avoided. Phytosanitary regulations of importing countries, or contractual obligations at export terminals, often stipulate fumigation on board ship or in some instances on feeder barges. This is to ensure absolute freedom from infestation or, if an infestation is discovered on arrival at port of destination, regulations stipulate fumigation prior to unloading. In many instances, this stipulation is neither practicable nor feasible, and often results in less than total control, increased costs for pest control, undue hazards and unwarranted delays. If a quarantine risk does not exist (ie live infestation of P. truncatus or T. granarium or other nominated quarantine pest are not found on compliance inspection) then it is advisable (in most instances) to offload the consignment into a transit shed, segregated from other cargoes, and fumigate under gas-proof sheeting (for bagged consignments) or into fumigable silos for bulk consignments.

Phytosanitary Certificates are of little inherent value unless (he countries issuing the certificates do so in the spirit intended for these documents. The requirement is for the exporting country to carry out a compliance inspection using Governmental Inspection Services to substantiate that the consignment is found to the best of his knowledge to he free of quarantine pests and substantially free of other injurious pests and that the consignment is believed to conform with the current phytosanitary regulations of the importing country. It has been clearly established that standard sampling procedures even when carried out thoroughly are very unlikely to detect low levels of infestation. Therefore it is logical that, where an importing country is not confident that the exporting country will he certain to detect the presence of quarantine pests, the importing country should require a specified disinfestation treatment to be carried out to the grain or other commodity before accepting it. Specific and proven intransit fumigation or fumigation at discharge port can be considered in this context, hut clearly the exporting country should give close attention to all aspects relating to accepted grain management practice within the post harvest system prior to grain reaching export terminals. New and improved inspection techniques and appropriate treatment schedules prior to loading should he introduced to avoid the necessity for in-ship fumigation. However, currently, the use of fumigants is likely to increase and therefore consideration of legal, trade and safety considerations regarding its use is essential (Ref IMO Recommendations, TDS #14)

Ships vary enormously in design, construction and standard of maintenance, and there is established methodology to ensure that any space is gas-tight at the time of inspection and use. The testing of work spaces for freedom from toxic gases is at best an inexact or spatial measurement. Due to the dynamic nature of the fumigation operations, there can be no guarantee that such tested areas will remain fumigant-free for any length of time, particularly when the vessel is in motion, or there is a change in atmospheric conditions. There is, therefore, a potential risk to personnel on-board ship even in the absence of any emergencies. Should there be a need for someone to enter an area under fumigation, there is an increased risk even when good quality protective equipment is available, and is correctly used.

During any fumigation, every attempt is made to retain the gas and restrict gaseous interchange. For ventilation, the reverse must occur. A cargo hold meeting a satisfactory standard of gas tightness and dosed at, for example, 1.5 g phosphine per cubic metre, will retain a phosphine concentration level above the TLV for several weeks, unless specific steps are taken to ventilate it.

The most efficient ventilation of a conventional cargo hold is obtained by providing a through draught. This allows air to enter at the bottom of the hulk and displace the gas through the top of the hold. Provision of a single opening does not give a through draught and ventilation under these conditions will he restricted. Under these conditions a dangerous level of phosphine could he maintained in a grain bulk for many days, although this will not he apparent if only the region close to the ventilation opening is tested with gas monitoring equipment.

Most grain-importing countries require inspection of holds and cargoes prior to commencement of discharge for plant health reasons. Inspectors carrying out this task would be at risk if they entered space that had been fumigated.

It is necessary, on all grain vessels, for personnel to enter holds before and during discharge. Port labour and others would, therefore, have to be trained and equipped to carry out such operations safely. It is easy to imagine the situation where people could, and would, unwittingly enter treated holds and thereby become exposed to potentially lethal amounts of fumigants.

In general practice, the aeration procedure for ships requires the opening of the main hatch covers and all man hatch covers. Gas concentrations should he monitored at approximately 1 m above the grain surface (waist height) every 30 minutes until the fumigant gas concentration is at or below the legal limit. At this time, it is safe to start the discharge of grain using pneumatic1 or grab-type equipment. If the grain is to he unloaded by bagging in the hold or the cargo is shipped in bags, ship-hoard fumigation is not recommended unless the hold is force ventilated.

1 Pneumatic discharge requires continous presence of people in the ship hold, this necessitates continous minitoring of gas concentrations as this may change as the gram is being removed,

During the operation of pneumatic equipment it is generally considered safe for workers to be on the grain surface, but sleeping, lying or sitting on the grain surface must he avoided. If it is necessary to enter a treated hold which is being unloaded by non-pneumatic methods, monitoring of fumigant gas levels should he carried out routinely to ensure that gas concentrations do not exceed the 0.3 ppm TLV level for phosphine, or 5 ppm for methyl bromide.

The minimum procedure for aerating the holds of a bulk cargo type ship requires the opening of the two most widely separated hatches in each hold and installing fans to blow air into the hold to "wash" the grain surface of the fumigant gas, except where fully effective forced ventilation systems are used. Air must not he pulled out of the hold unless using a forced ventilation system as it will also pull the gas out of the grain mass and will significantly prolong the aeration period. When the headspace of the hold has a fumigant concentration of the TLV or less, it is safe to enter the hold while pneumatic discharge equipment and/or fans are in operation. In the event that grain discharge is stopped, gas monitoring should be done at regular intervals and entrance to the fumigated holds should be prohibited until gas concentrations are at or below the TLV level. Reduction of gas concentrations can he accomplished either by turning on the pneumatic off-loading equipment or using tans as described above.

Methyl bromide is the only option for fumigations where short voyage times would not permit adequate penetration and distribution of phosphine. The techniques used for methyl bromide fumigations generally do not give adequate distribution of the fumigant without the use of a re-circulation system. (See Section 3.3.3.2)

3.3.1.1. Suitability of vessels:

Many vessels cannot he effectively or safely fumigated while intransit or at anchor. These vessels should only he fumigated while berthed and with the crew removed.

It is recommended that only the following types of vessel should he fumigated intransit or at anchor.

1. Bulk dry-cargo vessels including ocean-going barges.
2. Tanker-type vessels.
3. Liquefied natural gas carriers converted to bulk carriers.

Vessels being considered for intransit fumigation should only be fumigated if the Fumigator-in-charge or another qualified person has examined and tested the ship and determined that the holds can be safely fumigated. This should he done before the vessel is loaded so that all of the hold space can he examined and tested. If the cargo holds have not been correctly tested to the satisfaction of the ship's master or the harbour authorities the vessel should remain in port for gastightness checks (1-4 days for phosphine if a re-circulation system, Phyto Explo, or other fan powered injection systems are used, or 3 - 5 days if a passive distribution system is used) or alternatively the ship can sail with a qualified fumigator on board to check the safety and advise accordingly during the voyage (Ref IMO 3.4.3.9.1. and 2, TDS #14).

The fumigator should he accompanied by a ship's officer. Inspections should include:

3.3.1.1.1. Access areas to holds:

· Hatch covers (particularly the gaskets)
· Vents or forced draft systems
· Manhatches
· Other openings

3.3.1.1.2. Structural and other systems:

· coffer dams
· pumping systems
· all weather tunnels
· keel ducts
· electrical conduit
· bilges and bilge pumps
· smoke detector systems
· deck lockers
· bulkheads and decks
· refrigeration drain lines from galley
· antenna wires from crews quarters

3.3.1.1.3. Areas near crews quarters or other occupied areas:

The holds should be examined for obvious points of leakage but unusual conditions must be considered. There may be cross connections from the bilge to drains in the galley or other areas. Gas has been known to follow this path.

Smoke detectors draw air from the hold to a sampling point at the bridge in some ships. This could bring gas from the hold to the bridge and at least one fatality may have occurred by this means. It may not be sate to discontinue the use of the smoke detector but additional safeguards would he indicated.

3.3.1.2. Testing for leakage

A suitable method of testing for leakages (eg pressure or similar) will provide information regarding gas tightness and allow remedial sealing operations to he carried out prior to fumigation. Some crews like to operate radios in their quarters and will rig elaborate antennas. They have been known to drill through a common wall between a hold and their quarters in order to get the antenna wire to a distant point. This can permit gas leakage into the crews quarters.

Doorways to the crews quarters are often left open even when they are next to a fumigated hold. Again leakage can occur as a result.

Other areas are occasionally occupied by the crew and have been known to have high gas concentrations. Paint lockers and rope lockers may have hatches to the holds that are fumigated.

Crews will sometimes sit on the hatch covers or even sleep on them and can he overcome by very small amounts of gas leakage. All holds have vents and even though these may he well sealed at the time of sailing, the seals may later deteriorate.

A trained person must he on hoard the ship to measure the concentration and watch for unusual problems. He may he a ship's officer or may he part of the fumigation crew. Sufficient training and equipment are absolutely essential.

3.3.1.3. Key safety requirements in ship board fumigation (see IMO guidelines)

1. Never assume that ship's holds are gas-tight. The vessel must he examined and tested before loading to establish its condition.

2. Do not ignore the smoke detection system. Many of these systems bring air samples from each hold to the bridge. Under certain weather conditions, ventilation will not be complete and the air and gas can fill the bridge. Even running the smokedetection system for an hour or so can cause gas leakage.

3. Gas can travel through electrical conduit from a hold and this possibility should not be ignored. Check for every possible route of gas leakage.

4. If using gas-proof sheeting he sure that all tears are sealed before covering the gas-proof sheet with the weather proof tarpaulin. The weather proof tarpaulin is not gas-proof.

5. Dragging the weather-proof tarpaulin over the edge of the gas-proof sheets can pull the gas-proof sheet loose. Care is needed in this operation.

6. Do not use phosphine on grain that was loaded during rain.

7. Explain the safety rules to the crew before every fumigation so they will realise the importance of avoiding exposure to the gas.

8. Aeration must be checked at the bottom of the hold by instruments to assure safe worker re-entry. Do not depend on merely uncovering the hold and sampling from the top of bagged commodities.

9. If power ventilation is available for the holds, it should be run during the aeration. Do not depend merely opening the hatch to aerate methyl bromide from a ship's hold. If the ship is not equipped for power ventilation of the hold it is necessary to have a portable forced ventilation system.

10. When chloropicrin is used as a warning agent do not depend on the odour of chloropicrin alone to provide safety. Chloropicrin and methyl bromide may be sorbed and may disperse at different rates.

11. Do not depend on a given amount of time for aeration to be completed. Only tests with instruments can confirm that the gas level is below the TLV.

12. Do not assume that the ship has adequate respiratory protection. Check its presence and condition. Be sure key people on board know how to use this equipment.

13. Be sure that gas monitoring equipment is on hoard and that someone on hoard knows how and when to use it.

3.3.2. Ship fumigation while ship is evacuated by personnel and crew

If there is a possibility that gas can leak from the holds to an occupied or potentially occupied area, fumigations should only be done after the crew and all other persons have left the ship. The only persons remaining on the ship should be fumigation personnel that are equipped with respiratory protection and gas measurement devices.

Before the gas is introduced, the Fumigator-in-Charge should plan how the gas will he aerated to a safe level. This may mean placing fans in some areas if electricity is available or can he made available with portable generators.

3.3.2.1. Methyl bromide:

Where at least a 5-day period for fumigation is not possible only methyl bromide should be used, since phosphine can not guarantee an adequate kill of insect pests in a shorter period. Bulk grain cannot be adequately fumigated with methyl bromide unless a re-circulation system is used. This requires either suitable piping to be fitted prior to loading or the insertion of probes of an adequate diameter to the bottom of the hold after loading. The probes or pipe must be fitted to suitable high pressure fans to ensure re-circulation.

Bagged grain can be effectively fumigated with methyl bromide, hut good insect control still depends on air circulation to ensure that the gas is evenly dispersed and can be adequately ventilated. Fans must he used for at least one hour after gas release. This may necessitate obtaining electrical power through a portable generator, hut is the only way that a successful fumigation can he achieved. Sampling lines should, if at all possible, be installed for gas readings.

After the gas has been released at many points and the fans have run for at least one hour, the fans can be shut off and the seal can he checked for leaks. All leaks should be sealed by persons wearing respiratory equipment. The exposure period should he at least 24 hours. During this exposure period and prior to ventilation it is advisable that gas readings are taken to establish that sufficient gas has been retained to effect good insect control. Hatch covers and fumigation sheets can then he pulled hack and aeration started. Unless fans have been placed near the bottom of the hold during loading pipes must be introduced which will enable fans to ventilate the bottom of the hold adequately. Aeration is complete when the methyl bromide concentration in all areas is less than 5 ppm.

3.3.2.2. Phosphine:

If there is a fear of leakage phosphine should not he used. When hosphine is to he used to disinfest hulk or bagged cargoes on a berthed vessel it is advantageous to use a system which will ensure the most rapid distribution of gas. This again requires the employment of pipes inserted prior to loading or probes inserted after loading, together with the use of suitable fans. This still requires a minimum 5-day exposure period. Ventilation must he carried out as for methyl bromide until the phosphine concentrations are less than 0.3 ppm.

3.3.3. Ship board fumigation using phosphine

Phosphine is the only fumigant to he used for intransit fumigation of bagged or hulk cargoes. It can also he used when the crew have to be evacuated if the vessel is at berth (Refer to 3.3.2). A number of application methods are available to improve gas distribution throughout the cargo.

3.3.3.1. Bulk Cargoes:

Research studies by USDA, CSIRO, NRI, MAFF UK, have shown that, when using phosphine-generating formulations, prolonged exposure periods will normally be required for complete control of insects in bulk cargoes due to the slow and uneven penetration of the gas in this situation. (Refer to TDS #15)

Many different application methods for phosphine fumigation are currently used for intransit fumigation. These can be:

· Surface Application
· Trench Application
· Short probe system
· Long probe system
· Tubing to bottom of hold system

However, research over the past 7 years has demonstrated that, if a positive distribution system for circulating the gas in bulk cargoes is used, a far more effective distribution of gas is achieved while using less fumigant in a shorter time. Therefore, only systems which provide positive distribution of the gas throughout the hulk, such as re-circulation, the Phyto Explo, or other fan powered injection systems should be accepted in bulk shipments. With these systems an exposure period of as little as 5 days is normally acceptable.

3.3.3.2. Bagged cargoes:

Phosphine will penetrate more readily into bagged than into bulk cargoes and therefore, while it is preferable to use positive gas distribution systems, passive systems can be effective provide the phosphine-generating formulations are distributed evenly through the hold. This will necessitate the introduction of suitable tubing to the bottom of the holds prior to loading to allow even distribution of the phosphine-generating material after loading is complete.

3.3.3.3. Ventilation of cargo following intransit fumigation:

If a vessel arrives having been fumigated intransit, the master should inform the port authorities prior to berthing (Refer IMO Recommendations, TDS #14). If this Notification is received, or if a Plant Quarantine Inspector during inspection finds that intransit fumigation has been carried out, a suitably qualified person must check the holds to determine that any levels of gas remaining are below the sate minimum before the Plant Quarantine Inspection is completed, and prior to discharge commencing.

3.3.4. Application after loading bulk maize without prior installation of tubing

The Phyto ExploR is a new process for grain treatment enabling the automatic installation of a disposable perforated or non-perforated shaft, having an inside diameter of 63 mm, to depths of up to 20 meters and more. It enables fan-assisted injection of phosphine or methyl bromide to he made effectively into deep bulks (Refer to TDS #15).

The shaft is particularly well suited to the fumigation of grain on board ships, in silos or stores where the diffusion of insecticidal gas into the hulk of the grain is required, since the system can be adapted to use phosphine, methyl bromide and a wide range of other formulations. It can he used to re-circulate methyl bromide, or introduce phosphine. deep into hulks to provide rapid and even distribution.

Phyto ExploR is a simple, rational and stand-alone means of fumigating a vessel which has already been loaded for example, or silo cells which have already been filled, without any commodity handling or prior installation required.

The technology meets all the requirements of loaders, stores and transporters alike, who are often constrained by current fumigation processes which can be the cause of costly unloading and lost time. The Phyto ExploR fumigation system can be used with methyl bromide. It consists of a partially-perforated shaft (the bottom 2 metres is perforated) being inserted to near the bottom of the hold (hold depth 18 metres and shaft inserted to 17 metres) and then the hot vaporised methyl bromide can he applied to the surface of the grain. A fan located on deck connected by pipe to the Phyto Explo shaft from the outlet of the fan, and a suction pipe fixed in the free space above the surface of the maize and connected to the suction side of the fan. The fan is running continuously throughout the. fumigation and the ventilation period.

In recent trials, methyl bromide was applied at a dosage of 32g/m3, with the hulk maize temperature in the hold being treated at 28 °C.

The following results were achieved:

· A relatively even distribution of fumigant was rapidly achieved, and maintained throughout the fumigation period.

· Concentration time (C x T) products achieved were in excess of those required to eradicate all specimens of the target species (Tribolium spp.) at the prevailing temperatures.

· There was a limited amount of gas leakage from hatch covers which could not he prevented. Sorption of fumigant by the grain must also have reduced the concentration despite the relatively high temperatures.

· A short and thorough ventilation was achieved after the fumigation was completed, and with the holds open.

· Concentrations of methyl bromide ranged from 14-22 mg/m3 just prior to ventilation (20 hours).

3.3.5. Fumigation of shipping containers

Cereal grains and some other products are fumigated in shipping containers either before shipment or intransit. When containers are fumigated and aerated prior to loading on hoard ship, hazards are minimised. Both exporting and importing countries may have restrictions that need to be checked before a fumigation is undertaken.

· Containers should not be loaded until gas concentrations have reached equilibrium.
· Proper warning signs must be affixed on the container.
· The Master of the ship should he notified that some cargo has been fumigated.
· Shipping documents should show:

· Dale of fumigation
· Type of fumigant
· Amount of fumigant
· Necessary precautions

· Stowage should he above deck and more than 6 meters from:

· Ventilator intakes
· Crews quarters
· Any regularly occupied space

· If fumigated containers are stored in holds below decks, that hold should be considered a fumigated hold and all restrictions for intransit fumigation of holds would apply.

· It is recommended that fumigants should not he introduced into the container after it is loaded on board the ship.

· Fumigation of containers can be successful because of the long exposure period but attention to proper fumigation techniques can help assure both efficacy and safety.

It is important therefore, to ensure that the most appropriate fumigant is selected, that it is properly introduced, and that the container is sealed well enough to retain the gas for the required period of time at the required concentration.

3.3.5.1. Choose methyl bromide with chloropicrin only if:

· Commodity is raw unprocessed grain and exposure time is short.

· The warning agent is needed for safety reasons and product will not be damaged by either gas.

3.3.5.2. Choose methyl bromide if:

· Product is to be aerated before shipment.

· Exposure time is less than 5 days.

· Phosphine or other evolved gas could harm product.

· Potatoes or other starches can be damaged by ammonia from aluminium phosphine;

· Copper, gold and silver can he corroded by phosphine.

3.3.5.3. Choose Phosphine if:

· Deep penetration is needed.
· Exposure for more than 5 days is scheduled.
· Product could he damaged by methyl bromide.
· Additional methyl bromide fumigations might present residue problems.

3.3.5.4. Methyl bromide application:

· Inspect the container before fumigation. Seal any holes or tears and examine the door gaskets to determine the amount of sealing required.

· Place the injection hose so that methyl bromide is fully volatilised to a gas before contacting the product.

· If enough head room exists, fasten hose to the ceiling pointing towards the rear.

· If only a small amount of space exists, consider covering cargo with a plastic sheet, particularly in cold weather.

· Use an elbow at end of hose- with holes drilled in the sides so that gas will be released in four directions. Fasten to centre of the ceiling.

· Use a heat exchanger to assist with the release of the gas.

· Bring the treating hose out at a door corner and close the door carefully to assure that the hose is not pinched.

· Seal the door with double layers of tape to prevent leakage.

· Determine the volume of the container. This is often painted on the side of the container but if not, the fumigator will have to measure the length, width and height to determine its volume.

· If the gas is to he dispensed from a large cylinder, the cylinder should be placed on a scale so that the exact dosage could be released.

· Small cans containing 454 g of methyl bromide are commonly used since measurement is easy and bulk fumigant containers do not have to he taken to remote areas. These cans should only be opened with a special applicator, which should be regularly and thoroughly checked before each use to be sure that the gasket around the probe is in good condition and that all connections are tight. The hose should also be checked for kinks or damage before use.

· Carefully insert the can so that the probe does not puncture the can at the seam as this would cause leakage.

· To release the gas, tighten the clamp while holding the can away from the body. If there is any leakage, set the can down and immediately remove any contaminated clothing. Do not re-use clothing until it has been washed in hot water and dried. Shoes will hold the gas longer and probably should he discarded.

· Dispensing cans must be held away from the body since there could he leaks that are not visible but could cause burns. The fumigator should be standing, not sitting or kneeling to also prevent burns.

· When the gas is almost exhausted, point the spout down to help drain any remaining liquid methyl bromide.

· When no more gas is seen going through the delivery line and the spout has started to warm, the can may be removed from its applicator but it may still contain some gas under pressure. Set the can on the ground and allow it to ventilate for at least 5 minutes.

· Introduce additional gas, if needed, in a similar manner.

· The hose can now be pulled out and the small gap at the corner of the door sealed. If the hose cannot be removed, push it hack into the container and seal. If it will not move either direction, cut if off at the doorway and seal the end with tape.

· Use a halide leak detector or other device to now check the doors and hatched for leaks and repair if necessary.

· Place warning signs on the container doors and other conspicuous place(s) and lock the doors with a steel, padlock or similar to prevent entry.

· Drain the injection hose and purge with air if possible. Carefully coil this up again. Accidents have occurred when small amounts of liquid methyl bromide were accidentally splashed into a person's eyes from a supposedly empty hose.

· Complete fumigation forms (including data, fumigant type and dosage applied, serial number of container).

3.3.5.5. Phosphine fumigation of shipping containers:

· Inspect the container before fumigation is started. Seal any holes or tears. Examine the doors and hatches and plan the sealing of these.

· Seal all doors or hatches except for the one that will be used to introduce the gas.

· Determine the volume of the container from printed capacity or from measurements and calculate the dosage.

· Bulk grain can he surface treated due to the short depth and long exposure.

· Prepacks, sachets, or sacks with FumiCels should be fastened to strings to facilitate later removal. It is better to suspend these above the product hut they will he effective as long as they do not touch each other.

· Sealing doors and hatches must he done carefully or the gas will leak out quickly. Water-tight hatches do not prevent gas loss. It is better to cover the hatch with a small section of plastic before the lid is clamped down. Some fumigators seal the plastic to the edge by lining the edge with tape that has adhesive on sides.

· Place signs on doors or other conspicuous place.

· Record fumigant use, amount, date, and identification number of container treated.

3.3.5.6. Key safety items in rumination of shipping containers:

· Tablets or pellets of aluminium or magnesium phosphide should not he placed directly on processed foods such as polished rice.

· FumiCel Plates can break open in transit and should never be placed directly on processed foods.

· Methyl bromide should never be released between bags. It should be released into the head space using techniques that will assure even distribution.

· Don't consider watertight hatches to he gas tight. All doors and hatches should he sealed unless they have very tight rubber seals in good condition, and are tight-fitting so the gasket is compressed when the hatch is closed.

If there is a possibility that a container may be stowed below deck, it is essential to fumigate and aerate it before loading to avoid the restriction that any fumigated container in a hold makes the entire hold subject to regulations of a fumigated hold. Alternatively the container must he stowed on deck by prior agreement (Refer IMO 3.5.1, TDS #14).

· Use at least two warning signs securely fastened to the fumigated containers to ensure that ship's crew will be warned that a container has been dosed with fumigant gas.

· Examine methyl bromide applicators before use to ensure that gaskets are in good condition.

· Never hold cans of methyl bromide close to the body while releasing fumigants. Escaping gas can cause burns.

· Never sit or squat while releasing gas as the concentration will be higher closer to the ground.

· Remember that some gas will almost certainly remain in cans when they are unclamped. Hold cans away from the body and throw to the side, leave until the can is totally empty.

· Some gas will he trapped in the hose. Coil carefully to avoid spilling some gas on other workers.

· Do not put hoses or cans into enclosed occupied truck spaces.

· Never crush "empty" cans with the foot. Remaining gas will be forced out of puncture holes and possible on to the toot.

· If methyl bromide is to he used, application lines should be installed at the front and preferably also at the rear of the container and secured near the roof. They should be secured well enough that the whipping motion that occurs when the gas is released will not cause the lines to come loose. It is important that the gas does not contact food directly while it is still in liquid state. If it is necessary the gas can he introduced via large evaporating containers made of steel or glass hut never aluminium or magnesium. Alternatively a vaporiser (heat exchanger) can be used.

· Calculate the volume of the container, and calculate the dosage based on this volume.

· Release the methyl bromide into the container with applicators on cans or from a cylinder.

· Check the entire outside of the container for leaks using an appropriate device (halide lamp detector or detector tubes).

· If phosphine is to be used, it must be placed inside the trailer before the door is finally sealed, hut after all other openings are sealed. Tablets or pellets can be placed on trays and located at several positions in the trailer. FumiCel plates can he used as long as they do not contact processed foods. Overdosing will not compensate for a leaky container.

· After completing the application of fumigant lock the doors with a steel bolt or similar to prevent entry.

3.3.6. Ship inspection

Documents:

1. Examine the Plant Quarantine and Fumigation of Cargo Certificates from the country of origin. There should also he a certificate stating that the empty vessel was cleaned and 'treated With a residual insecticide before loading. Does the Phytosanitary Importation License agree with the vessel's cargo manifest?

Time of Inspection:

2. The cargo should be examined during the cool part of the day because any insect will move deeper into the grain from hot surface areas.

General Inspection:

3. The Plant Quarantine Inspector (PQI) should he present when each hatch is first opened to note any flying insects. Also make a note of any signs of mould or damp on the surface of the grain.

4. If possible examine the girders supporting the deck and any other flat surfaces for any inject infested spillage.

5. Examine the surface of the grain, particularly damp or mouldy areas, for insect activity.

Sample inspection:

6. Take samples from all parts of the surface of the grain, sieve and examine for free living insects and insect damaged grain. Samples should be examined in a shaded place on board the ship. If it is a bagged cargo lift up several of the surface bags and examine exposed areas for signs of insect activity including moth webbing. Where ventilation ducts have been built into the stack shine a torch down them and note any flying insects.

7. Samples may be obtained from deep in the hulk by using; vacuum sample. For this purpose an industrial vacuum cleaner can he modified. Several pieces of water pipe each about 2 m long will he required. One should he fitted with a bullet shape(end and a slot cut into the side of the pipe which should be big enough to accept maize grains. Pipes can be joined one to another with a threaded collar.

8. The open end of the modified pipe sections are attached to the vacuum intake with a flexible pipe, and the machine switched on. As grain is sucked into the vacuum, examine for insect: and then discard. Fit another length of pipe to the first piece and repeat the operation. By this means grain samples can be obtained from any depth. It should be noted that samples obtained this way are not representative of the hulk and should not he used to determine grain quality, because they will contain proportionally more dust than the bulk.

9. Before using the vacuum cleaner make sure that the electricity supply is compatible with the vacuum motor. Several supplier: market vauum probes for sampling grain, hut are relatively expensive.

Reference sample:

10. A reference sample should he stored in the laboratory and examined at intervals to find out if any insects emerge. If any: insects are found this will indicate that the bulk is also infested and that remedial action may be required. Once the cargo has been accepted for distribution by the importer such samples can be discarded.

Interpretation of Sample Inspection:

11. Any insects recovered from samples must be identified; if in doubt take the to the PQ laboratory for identification. Based on insects recovered, a decision must be made as to how the cargo is to be handled. If there are no live insects it can be released for discharge. The cargo must conform to the relevant national Plant Protection and related Plant Quarantine Regulations, with respect to inspection compliance at ports of first import. If the cargo is to be re-exported to another country, a Phytosanitary Certificate (re-export) will be required, otherwise permission for the goods to enter can be given if no live insects have been recovered or following fumigation according to the PQ Regulations.

12. Any disinfestation which takes place on board the vessels is at the expense of the exporter/ship owner. If any pest control operation takes place after the vessel is discharged this will be at the expense of the importer.

3.3.7. Fumigation of enclosed metal truck and rail trailers

These vehicles and containers vary in their condition. Some are used to transport food or grain and small amounts of these materials can lodge in cracks and crevices and permit residual infestations of insects. In some instances it may be illegal to fumigate these units if they are travelling on the road. They can be fumigated after being placed on flat-bed rail cars, as long as they are aerated prior to unloading. This restriction means that most fumigations are carried out whilst the trailer is parked rather than intransit.

The ability of trailers to hold gas varies with the type as well as the condition. Trailers with wooden floors will allow gas loss through and around the wood planks. Reefer or refrigerated meat trailers have metal floors but they usually have two or four drain holes in the corners that can allow gas loss. Reefer trucks normally have good door gaskets when new but these deteriorate rapidly. Reefer trucks may also need additional sealing around the refrigeration unit but this unit can sometimes be run (without the cooling) to circulate gas within the space.

Fumigation failures with these units are so common that quarantine fumigations under for example the USDA Animal and Plant Health Inspection Service (APHIS) regulations, require that trucks be covered with a gas-proof sheet. They also demand fans inside the unit and often require ducts attached to the fans. Therefore every effort should be made to avoid the necessity for this type of fumigation by specifying precisely what is required before products are moved between countries. For example: Specifying that the commodity must be fumigated with a specified product using a specified method and that the Phytosanitary Inspection Services of the exporting country must check the procedures are followed correctly and certify them to the importing country. If a possible source of insect infestation is the trailer itself, it is better to fumigate it whilst it is empty, and then load the disinfested products to he transported. With methyl bromide it is possible to use a high dose and short exposure period in empty trucks without any concern for residue problems. Fans are required in all fumigations with methyl bromide.


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