Guidance and Interpretation Series 4 Fumigation in Freight Containers

Transcription

1 Fumigation in Freight Containers Hazards for Personnel in Ports and the Wider Cargo Handling Industry (first printed April 2005) 1 Introduction 1.1 This Guidance and Interpretation document addresses the hazards to port personnel arising from the practice of fumigating freight containers in transit and, to a lesser extent, arising from containers fumigated in ports. The guidance has been written specifically in relation to the hazards of entering a container in which fumigant is present at ports. However, it may also be relevant to such container entry in other sectors of industry. 1.2 Fumigated cargoes, transported by sea, should be carried in accordance with the International Maritime Organization s (IMO) Recommendations on the Safe Use of Pesticides in Ships which is contained in the Supplement volume of the International Maritime Dangerous Goods (IMDG) Code and is concerned with the fumigation of bulk and containerised cargo. 1.3 It has long been the practice to fumigate bulk cargoes such as cereal and animal feed in transit on board ship. Precautionary control measures are relatively easy to apply on board ship, are more or less standard within the marine industry and crew safety measures are carried out under control of the ship s Master or senior officers. Notification to the port of entry is routine. 1.4 Fumigation of goods in freight containers presents a different set of problems. The same highly toxic chemicals are used in containers as on board bulk ships. However, when a container that contains fumigant chemicals leaves the place at which it was fumigated, no-one can practically supervise the hazard unless they are aware of the presence of the fumigant. Any person who later enters the container can therefore be unknowingly exposed to dangerous levels of highly toxic chemicals. 1.5 Hazard warning measures exist and fumigated containers, shipped by sea, come within the scope of the IMDG Code. Compliance with the IMDG Code by member states has been made mandatory by the IMO. Hazard warning measures required by the IMDG Code include: Warning signs on containers; Transport documents describing the fumigation method and date; and Requirements to declare fumigated containers on ships manifests. It is generally acknowledged, however, that there is widespread noncompliance with these requirements. Personnel may therefore be instructed to identify whether hazardous levels of fumigant are present before entering the container. 1

2 1.6 This document seeks to set out the nature of this hazard and identify practical measures that can be taken to protect personnel who are required to enter containers This document does not consider the hazard of depleted oxygen levels within freight containers. Personnel should be advised that even when no fumigant is detected, oxygen levels within the container may still be insufficient to support human life and should be treated as a confined space under The Confined Spaces Regulations There is no link between oxygen levels and application of fumigant. Why Fumigate Goods in Freight Containers? 2.1 To protect cargo from infestation during transit Grubs and larvae of insects and other species can infest cargo, as well as packaging, dunnage etc. associated with the cargo, at any stage during harvesting, manufacture, processing, storage, packing or transport. These can spoil foodstuffs, textiles, leather goods, furniture, art and antiques, affect electronic equipment, contaminate sterile goods or deface consumer packaging or labelling, making the goods unfit for sale and therefore valueless. Fumigation kills all stages in the life cycle of pests, thus eliminating the risk of devaluing the cargo. 2.2 To protect the importer s premises Importers, particularly those that operate food processing plants, make great efforts to eliminate infestation in order to prevent the invasion of the importer s local storage or processing plant from infestation carried in incoming cargo. Consequently, they regularly fumigate their premises and may insist that goods delivered to their premises are certified free of infestation by means of fumigation. 2.3 To protect the environment Fumigation protects the wider indigenous environment from invasion by alien species carried in cargo or packaging arriving in freight containers. Indigenous species of trees and crops can be seriously affected by the introduction of alien species via imported cargo. Many countries have introduced phytosanitary legislation to prevent the arrival in their country of alien species. Protection is achieved by requiring imported timber in bulk, timber in containers, timber in container floors, goods in containers, timber packing cases in which goods are packed, pallets and timber dunnage to be certified free of infestation. Certification is achieved by 2

3 3 proof that timber has been treated on land prior to shipment, or by fumigating the container after the load has been packed. When is a Container Fumigated? 3.1 Fumigation prior to shipment A container may be fumigated in the exporting location, prior to shipment, and then ventilated prior to loading on to a vessel. This still poses a limited hazard to people entering the container at the port of import. Although fumigant gas may be vented from the container, during the voyage, gas trapped in the cargo may subsequently be released (desorbed) 1 and the gas level inside the container may again reach danger levels. The risks are much higher if fumigant residues are not removed prior to shipment, in which case the container should be regarded as being fumigated in transit. 3.2 Fumigation on landing A container may be fumigated in a port on landing from a vessel. During the fumigation process the container should be placed under the control of a competent person whose duty it is to prevent access by port workers to the container during the fumigation process. The port management should work with the fumigation controller to develop a system for labelling any container into which fumigant has been introduced, and for preventing or strictly controlling the further movement of that container until the fumigant has been removed. 3.3 Fumigation in transit Fumigation in transit poses the greatest hazard to port personnel and mariners, because toxic fumigant chemicals are introduced into a container, the vents of which have been sealed and it is loaded onto a ship. Some fumigant chemicals start to work immediately, others work by reacting with moisture in the air over an extended time period during the sea voyage, releasing the fumigant inside the container. In order to be effective the gas needs to be kept within the container, so the vents and doors are frequently sealed with adhesive tape. There may still be fumigant gas inside the container when the container is landed. This gas will be hazardous to any person entering the container. All containers shipped while under fumigation, regardless of the chemical used, should be signed with the following symbol, on the container doors: 1 Desorption means the slow release of gas from cargo containing air pockets such as bagged or bulk cereals, and cardboard and timber cases. 3

4 Fumigation warning sign The marking should be black print on a white background with lettering not less than 25mm high DANGER THIS UNIT IS UNDER FUMIGATION WITH [ fumigant name*] APPLIED ON [ date* ] [ time* ] DO NOT ENTER Not less than 250mm Not less than 300mm 4 Principal Types of Chemical Used in the Fumigation of Containers (in order of frequency) 4.1 Phosphine UN 2199 It is estimated that 95% of fumigation of freight containers in transit is done using phosphine. It can be applied by personnel with little technical training Sachets, tablets or pressed plates containing magnesium phosphide or aluminium phosphide are placed inside the container. They generate phosphine gas when exposed to moisture in the air. The gas has a slight fish and garlic smell. The original material breaks down into a powdery grey residue which resembles cigarette ash The rate of generation of phosphine is affected by airborne moisture, temperature, and the degree to which the phosphine generating material is exposed to air and can take some weeks. The UK sets the Workplace Exposure Limit (WEL) for phosphine at 0.3 parts per million for a maximum of 15 minutes. It is unsafe to enter a container for more than 15 minutes if the gas level is above this. Other countries may set a slightly different threshold level, or call the WEL the Threshold Level Value, but the level will be similar. There is no exposure allowed averaged over an 8 hour period. 4

5 4.1.3 Symptoms of poisoning by inhalation of phosphine include nausea, vomiting, headache, weakness, faintness, pain in chest, cough, chest tightness and difficulty breathing. Pulmonary oedema (the presence of excess fluid in the lungs usually due to heart failure) can follow, usually within 24 hours, but sometimes this is delayed for some days. 4.2 Methyl bromide (bromomethane) UN 1062 Fumigation with methyl bromide is a relatively rapid process a 40 ft. container can be fumigated and vented efficiently within a hour period. This makes it a good method of quayside pre or post shipment fumigation. There is no odour so it is suitable for treating foodstuffs. However, this makes it more difficult to detect. Methyl bromide is sometimes used for in-transit fumigation of containers, although it is not recommended by the IMO. The use of methyl bromide is being phased out as an ozone depleter under the terms of the Montreal Protocol. (The Montreal Protocol on Substances that Deplete the Ozone Layer, United Nations Environment Programme (UNEP), was adopted on 16 September 1987.) Methyl bromide is a liquid at ambient temperature, but is vaporised by heat or pressure during application. Application is generally either from a disposable one-use cylinder that is punctured and then shut inside the container or injected through a lance as a measured dose from a large cylinder from outside the container. These operations require some level of expertise to carry out safely. The UK 15 minute Workplace Exposure Limit (WEL) for methyl bromide is 15 parts per million for 15 minutes and it is unsafe to enter a container for more than 15 minutes if the gas level is above this. There is an 8 hour Time Weighted Average WEL of 5 parts per million Symptoms of poisoning by inhalation of methyl bromide include headache, dizziness, eye irritation, cough, nausea, abdominal discomfort, numbness of feet. Higher exposure will bring about unconsciousness, pulmonary oedema up to 30 hours after exposure, and damage to central nervous system, convulsions, loss of vision, balance and hearing. 4.3 Other chemicals used for fumigation Other chemicals occasionally used for fumigation include the following: Sulfuryl fluoride (has trade names such as Vikane and Profume) a potential replacement for methyl bromide. Formaldehyde Hydrogen cyanide 5

6 5 As these chemicals are rarely used for fumigation in transit, little is known about them in relation to shipping, which makes them difficult to identify in practice. However, their use may increase in future and relevant parties should be encouraged to record evidence of their undeclared use. Practical Hazard Problems 5.1 Freight containers can be safely fumigated in transit if the fumigant is applied in the proper way, and all parties follow the requirements of the IMDG Code, particularly the requirement to fix the fumigation warning sign on the container door and to declare the fumigation in the approved way. Hazards are created when this requirement is NOT followed and the danger is NOT recognised. 5.2 Special hazards associated with phosphine The method of application is simple and cheap, requiring virtually no knowledge of fumigation chemistry, and can be done anywhere, by anyone, during or after loading the freight container. This prompts application by unskilled and unsupervised persons, which can lead to Uncontrolled dose rate Fumigant manufacturers provide recommended dose rates for particular cargoes in 20 ft. and 40 ft. containers. The quantity of chemicals found in containers can vary greatly, even between identical loads, producing under and over-fumigated containers Unsuitable positioning If phosphine tablets or plates of phosphine are applied during loading, it is possible that they can be buried under bags or cartons. This will prevent air from coming into contact with the phosphine generator, inhibiting the chemical reaction until the cargo is removed, at which time the reaction will begin again, placing the unloaders at risk. The practice of burying fumigant also prevents residues being removed before unloading commences Variable temperature The chemical reaction is speeded up by higher temperature, slowed by lower temperature Dependence on moisture Airborne moisture is needed for the reaction to take place. Reaction will be inhibited if moisture content within the container is low, or if, as sometimes happens, the cargo loaders place desiccant inside the container to remove moisture. Therefore when the container is opened, allowing moisture to enter, the reaction can recommence. 6

7 5.2.5 Human contact with phosphine powder residue The residue left after magnesium or aluminium phosphide reacts with moisture to generate phosphine is magnesium or aluminium hydroxide. This is a light powdery grey substance like ash, which can remain toxic. If applied correctly, this should be positioned within an envelope or package of some kind, where it is readily obvious to unloaders when the container doors are opened, allowing suitably aware and trained personnel to easily remove the residue and dispose of it safely before commencing unloading (devanning). However, the original material is frequently introduced in tablet form, thrown randomly over and amongst the cargo. This leaves residue all over the cargo. Unloaders must avoid breathing in the residue, or getting it into their eyes or mouth. If they do not, unloaders are at risk of being poisoned by the residue, which may still be able to generate some phosphine. 5.3 Special hazards associated with methyl bromide Methyl bromide can only be applied as a vapour. The gas has no odour unless a stanching agent is added. So there will be no visual indication and often no odour to indicate that the gas is present. 5.4 Lack of control in application all fumigants When containers are loaded at remote locations, facilities for supervision and control of fumigation may be extremely limited. The persons applying the fumigant may not be suitably trained or experienced and may be totally unaware of how fumigant chemicals work and the hazards associated with them. In these circumstances, the quantity applied and the method of application can be very random. 5.5 Non compliance with the IMDG Code Freight containers are often packed and shipped by personnel with no understanding of the requirements of the IMDG Code. Accordingly, details concerning fumigation are often not passed along the transport chain to the shipping line. Indeed, shipping lines are often unaware that they have been carrying containers under fumigation. Some shipping lines may make a freight surcharge for carrying fumigated containers, so there is a disincentive for shippers to inform the shipping line of the fumigation. 5.6 Standard of notification Many fumigated containers are found, in transit, without warning signs on the doors as required by the IMDG Code. Of the containers that have signs, many are written in local languages that are not widely understood beyond a limited geographical area. The warning sign required by the IMDG Code has to be in English. 7

8 5.7 Standard of documentation The provision of documentation can also be generally inadequate. The reasons indicated in section 5.5 may help explain this. 6 Venting and Desorption 6.1 It is important to ensure that freight containers are properly vented by opening the doors and allowing the gas to escape. This can be a natural process, or can be accelerated by mechanical means such as blowers or extractors. The ventilation process can take many hours. 6.2 Care should be taken even after a container has been ventilated. Gas can be held in packages of cargo, then desorbed over a long period of time, even over many days, raising the level of gas inside the container to above the safe exposure level. Bagged cereals and cartons with large air spaces are likely to produce this effect. Alternatively, gas and the fumigant sachets or tablets can become trapped at the far end of a container by tightly packed cargo. 7 Origin of Fumigated Containers The majority of undeclared fumigated containers appear to originate in Far Eastern and Asian countries, with others from Africa and South America. However, this is only a reflection of world trade, and undeclared fumigated containers can and do originate in Europe and North America. All containers should be regarded as potentially containing fumigant. 8 What Can be Done to Protect Port Personnel? There are measures that can be taken to protect port personnel: 8.1 Educate and train Raise awareness among both employers and employees that any container can hold the potential hazard of undeclared fumigant Educate personnel in the hazards of fumigant gases and train them to: Look for warning signs on doors Look for taped doors and vents Look inside for packets or heaps of powdery residue Be alert for the fishy garlic smell of phosphine Advise employees not to tunnel into containerised cargo to retrieve packages. If tunnelling must take place, the atmosphere must be gas tested and safe to enter. 8

9 Instruct employees that it is preferable to unload containers progressively inwards, working across the face of the cargo, so that breathing of trapped or enclosed air inside the container is kept to a minimum. Supply dust masks and eye protection if cargo is heavily contaminated with powdery residue to prevent inhalation/eye contact. (Note: Dust masks provide no protection against gas). Provide personal gas detection monitors (see section 8.3 below). It is possible to protect unloaders from gas by providing them with appropriate respirator filter masks while working inside the container. These can provide full protection but must be selected, used and maintained carefully. They are difficult and uncomfortable to work in and are not a practical option for most situations. 8.2 Gas tests The most effective method of protection is to carry out gas tests when the container doors are opened for at least phosphine and methyl bromide, the two most common fumigants used (see below). If gas is found the container should be put aside for ventilation. Stain tube gas test equipment Glass stain tube equipment is simple in design and use, robust and reliable. A test for phosphine and methyl bromide can be carried out by a person standing outside the container using a lance inserted into the container doorway. In practice air is drawn by small hand-held bellows through a glass tube containing impregnated crystals which react with the gas for which the test is being done. If the air is contaminated by the gas in question, the crystals change colour. The function is not affected by moisture, but care has to be taken to warm the tubes to above 0ºC in sub zero temperatures. Also a reasonable degree of light is required to detect the colour change of the crystals. The tubes should be used in accordance with the manufacturer s instructions. In particular, they must not be used after their expiry date. Electronic (photo-ionisation) gas testing equipment Gas tests can be carried out that detect the presence of gases and their concentration levels. Similarly, equipment can confirm that there is a safe level of oxygen within the container. At the present time the technology is such that both the quantification and discrimination are poor. There are frequent false positives due to cross sensitivities and readings are not accurate enough for determining safe exposure levels. Therefore the use of these instruments at the present time is not recommended 9

10 Mass spectrophotometry Accurate and clear quantification of fumigant levels may be obtained using mass spectrophotometry. The sample process, and interpretation of results, has been considerably simplified in recent months. One sample can be analysed for multiple compounds, and if detection of a full range of gases is required the process is cost effective. However the equipment is not portable, so samples have to be brought to the equipment for testing and the capital outlay for the equipment is high. The equipment is most suited to a laboratory environment. However, further developments may make this a viable option for small scale testing in future. 8.3 Personal monitors Small electronic personal monitors are available for phosphine, but not for methyl bromide. Phosphine monitors can be placed inside the container while unloaders are working, or worn by individuals on outer garments. The location of an independent monitor is important both to ensure that any fumigant is detected and ensure that the reading is not compromised by ventilation at the door or external contaminants. Monitors issue an audible signal if phosphine levels reach the pre-set level and are useful as warning devices. However, they should not be used for the initial fumigation detection and measurement process. Also, electronic monitors have the disadvantage that they can respond to a range of harmless substances giving misleading alarm signals. 9 Personal monitors are also available to show the level of oxygen within the container. This would indicate a deoxygenated atmosphere but would not necessarily indicate that the atmosphere is free from fumigant. Facts and Figures 9.1 How widespread is the problem? In a survey, 300 containers were gas tested at random in Rotterdam. The tests indicated that 3.3% of the sample of containers gas tested were under fumigation, and only 40% of the containers that were under fumigation were marked and declared as being under fumigation. In the Port of Felixstowe 12,000 containers were gas tested in a sample period. The tests indicated that 2.7% of the sample were under fumigation, and only 12% of the containers that were under fumigation were marked and declared as being under fumigation. In this sample, 91% were found to be fumigated with phosphine and 9% with methyl bromide. Gas testing is carried out routinely, at Felixstowe, and the results are consistent. 10

11 9.2 Tolerable toxicity levels set by national agencies Only a low level of exposure to highly toxic materials can be tolerated by the human body. The tolerability levels in parts per million for the most common fumigant chemicals are shown in the following table. Different countries may set slightly different threshold limits for occupational exposure: Occupational Occupational Workplace Fumigant Exposure Limit Exposure Limit Exposure Limit (Netherlands) (Germany) (UK) 8 hr TWA Methyl Bromide 20 mg/ m 3 5 ppm (CH 3 Br) 1mg/m ppm 1mg/m 3 5 ppm 3 60 mg/ m 15 min WEL 15 ppm Phosphine Nil No 8 hr TWA (PH 3 ) 0.4mg/m ppm 0.15mg/m ppm 0.4 mg/ m 15 min WEL ppm Sulfuryl Fluoride - 8 hr TWA 5 ppm (SF 2 O 2 ) 20mg/m 3 5 ppm - 5 ppm - 15 min WEL 10 ppm Formaldehyde - 8 hr TWA (CH 2 ) 1.5mg/m 3 1 ppm 0.6mg/ m ppm 2 ppm - 15 min WEL 2 ppm Hydrogen Cyanide Nil No 8 hr TWA (HCN) 11mg/m 3 10 ppm 11mg/ m 3 10 ppm 11mg/ m 3 15 min WEL 10 ppm TWA Time Weighted Average m 3 - cubic metre ppm parts per million mg milligram WEL is dose related and is calculated as exposure level x time and is either specified as measured over a 15 minute or 8 hour TWA 9.3 Application rates / parts per million (ppm) Typical concentration levels reached inside containers being fumigated with common fumigants methyl bromide and phosphine are shown in the tables below. These should be compared to the tolerability toxicity table above. METHYL BROMIDE PHOSPHINE Fumigation 20 ft. Container 40 ft. Container Fumigation 20 ft. Container 40 ft. Container Rate per Cubic Cubic Capacity Rate per Cubic Cubic Cubic Metre Capacity 67.7m 3 Cubic Metre Capacity Capacity (m 3 ) 33.2m 3 (m 3 ) 33.2m m 3 16 grams 4,000 ppm 4,000 ppm 1 gram 660 ppm 660 ppm 32 grams 8,000 ppm 8,000 ppm 3 gram 1,980 ppm 1,980 ppm 64 grams 16,000 ppm 16,000 ppm 5 gram 3,300 ppm 3,300 ppm 11

12 The rates shown in the table above indicate typical values for rates of application, depending on the type of cargo, based on an empty container. The larger the volume of cargo inside the container, the greater the ppm value in the free air space. 10 Conclusion Increasingly, containers are being transported by sea under fumigation and often they are not documented or marked. There is a clear legal duty on shippers to declare fumigated containers to shipping lines and to ensure fumigated containers fully comply with the IMDG Code. Shipping lines can then manifest the units as hazardous and identify them to ports on landing. However, despite this issue being discussed internationally among national organisations responsible for maritime transport safety, the practice of fumigating containers in transit is increasing and there is no evidence that compliance with the IMDG Code or other related safety requirements is improving. Any container can hold the potential hazard of undeclared fumigant. This means that employers and authorities in ports who have responsibility for health and safety of persons entering freight containers should look carefully at the origin and nature of cargo in containers that will be opened by their employees. They should then carry out a risk assessment to determine whether that cargo could be under fumigation, and if so, to take appropriate action. 11 Recommendations for the Protection of Port Employees Entering Containers There are practical measures that employers can take to protect port personnel, if a potential fumigation hazard is identified. Containers should only be opened by a trained gas tester suitably competent to recognise the potential hazard of fumigant gases and to use gas detection equipment. Tests should be made for at least phosphine and methyl bromide in all cases. If traffic is specific to a particular commodity, tests should be carried out for any other fumigant substance associated with that commodity. The role of the gas tester is to detect gas when it is present and, when found, to place a warning sign on the container and prevent personnel from entering until appropriate ventilation has taken place to remove the gas and it is safe to do so. The employer should supply the gas tester with appropriate equipment to check that harmful levels of gas are not present in the container. Equipment should be arranged so that checks are carried out from outside the container so that the gas tester is not put at risk. 12

13 Gas detection equipment used in ports should be simple to use, and robust in nature. Glass stain tubes, as used worldwide by industry, fire brigades and military, are recommended. If no gas is detected, the test date and identity of gases for which tests have been carried out should be recorded with a date and time and a sign attached to the cargo stating that the container has been gas tested and is gas free. If the gas tester detects gas inside the container, it should be resealed, reported by the gas tester and labelled with a NO ENTRY - UNDER FUMIGATION - TOXIC GAS sign. The employer should have a system in place to ensure that any container containing gas is removed to a place where it can be opened and ventilated under the care of a qualified fumigation operator, fully trained to deal with the hazards of fumigant gas. Containers found to hold fumigant gas should be ventilated under controlled conditions by a qualified fumigation operator, until they are found by measuring devices to be free of gas, and therefore safe to enter. At this point a Gas Free certificate may be issued. Only a qualified fumigation operator should be permitted to issue a Gas Free certificate. The container should not be returned to the premises where unloading takes place until such a certificate has been issued. A qualified fumigation operator is an individual or organisation that has been certified as competent to safely apply, transport, handle, store and dispose of fumigant materials, with due regard the safety of himself, his own employees and other persons in the vicinity of the work. Local or national administrations may require individuals or organisations to be registered or licensed to do this work. In the UK, the British Pest Control Association may be able to advise a port authority on relevant fumigation issues. As detailed in Section 6, desorption should be considered. Care should be taken, even after a container has been ventilated, as gas can be held in cargo packages and released slowly over a period of time. Such a system, used in conjunction with the specific precautions listed in Section 8, should provide a robust regime that prevents employees being harmed by coming into contact with dangerous fumigation chemicals. 13

14 12 Useful References and Standards Health & Safety Commission: Safe Work in Confined Spaces The Confined Spaces Regulations 1997, L101. IMDG Code Supplement: Recommendations on the Safe Use of Pesticides in Ships IMDG Code Amendment 31-02: Entry for UN No: 3359, Special Provisions 302 & 910, Paragraph 5.5, Section Supplement: Use of Pesticides in Ships Section 3.5 & Annex 4 IMDG Code Amendment 32-04: Entry for UN No: 3359, Special Provisions 302 & 910 Paragraphs & UK Merchant Shipping Notice MSN 1718 (M) The Safe Use of Pesticides in Ships 13 British Pest Control Association (BPCA): Guidance Notes for the Ventilation & Testing of Imported Containers in the UK Acknowledgments This Guidance and Interpretation document was prepared by the Port of Felixstowe, Dangerous Goods Department of Hutchison Ports UK. The document draws on work done in Rotterdam port by EJ Wijdeveld. Technical fumigation data was provided by Igrox Ltd, Worlingworth, Woodbridge, Suffolk. This Guidance and Interpretation document was developed in consultation with PSSL subscribers and other industry stakeholders, including the Health and Safety Executive 14

15 Notes 15

16 GIS4 This Guidance and Information Series Leaflet has been produced by Ports Skills & Safety Ltd. Further copies are available from: Port Skills & Safety Ltd, Africa House, Kingsway, LONDON WC2B 6AH Tel: ; Fax: