IMDG Dangerous Goods Awareness common mistakes
IMDG Dangerous Goods Awareness · Understand the traps and how to avoid them.
Treating the IMDG Code as if it applied to every dangerous goods movement, including road-only or air-only consignments, instead of identifying when the sea leg brings the Code into play.
Candidates memorise the Code's contents but never learn its legal basis under SOLAS chapter VII and MARPOL Annex III, so they cannot articulate the trigger for application or the relationship with national modal regulations.
What to do instead
Build a one-page map: SOLAS VII/MARPOL III give the Code mandatory force for packaged dangerous goods carried by sea; distinguish port-to-port sea carriage from the road feeder legs governed by ADR/RID; note that the Code applies to all ships regardless of tonnage when carrying goods to which it applies. Practise with short scenarios asking 'does the IMDG Code govern this leg?'
Assigning a class from the substance name alone without checking the Dangerous Goods List entry, packing group and any special provision that reclassifies or excepts the substance.
Names like 'paint' or 'ammonia solution' feel self-explanatory, and candidates skip the alphabetic index and the DGL columns that carry packing group, subsidiary risk and special provisions.
What to do instead
Adopt a fixed lookup drill: find the entry in the alphabetical index, go to the DGL, read columns 1-6 in order (UN number, name, class, subsidiary risk, packing group, special provisions), then read the packing and stowage columns. Practise on ambiguous names such as UN 1263 PAINT (with packing group determined by flashpoint) and UN 2672 AMMONIA SOLUTION.
Ignoring subsidiary risks and the precedence-of-hazard rules, labelling only the primary class on packages and in the transport document.
Candidates learn the nine classes as isolated labels and do not practise the class precedence table, so they miss when a subsidiary risk must be shown or when a substance is assigned to a class other than the one the chemistry first suggests.
What to do instead
Work through the precedence-of-hazard table with worked examples (e.g. a substance that is both toxic and flammable), then apply the rule that subsidiary risks appear on labels and in documentation. Create flashcards pairing a substance with its primary and subsidiary risk and the label set required.
Confusing packing instructions, IBC instructions and large packing instructions, or applying a packing instruction without checking the special packing provisions attached to that UN number.
The packing column contains codes like P, IBC, LP and R with numeric suffixes, and candidates treat them as interchangeable or stop reading once they find the instruction number.
What to do instead
Learn the prefix meanings (P = packagings, IBC = intermediate bulk containers, LP = large packagings, R = special packagings) and always read the special packing provisions column alongside. Practise by taking five UN numbers across different packing groups and writing out the full packing requirement including any PP or B codes.
Marking and labelling packages with the correct hazard class but omitting the UN number, proper shipping name, or marine pollutant mark where required, or placing labels on the wrong face or size.
Candidates focus on the diamond label as the visible symbol of dangerous goods and treat the accompanying text marks and placement rules as detail to skim.
What to do instead
Use a package mock-up checklist: UN number, proper shipping name, labels for primary and subsidiary risks, marine pollutant mark where applicable, orientation arrows for liquids in combination packagings, and label durability and placement on the package surface. Apply the checklist to three different consignments and compare against the marking and labelling chapter.
Completing the dangerous goods transport document with generic descriptions such as 'chemicals, n.o.s.' or 'hazardous goods' rather than the proper shipping name, class, UN number and packing group in the prescribed sequence.
Candidates write declarations as narrative prose and do not memorise the required information order or the additional entries such as marine pollutant designation and flashpoint for certain classes.
What to do instead
Memorise a model declaration line and reproduce it from memory: UN number, proper shipping name, class (and subsidiary risk), packing group, plus marine pollutant and flashpoint where required. Then draft a full multimodal declaration including shipper's declaration, container/vehicle packing certificate and emergency contact information, and self-mark against the documentation chapter.
Applying segregation only between different classes and ignoring the segregation groups, the 'away from', 'separated from' and 'separated by a complete compartment or hold' distance definitions, and the segregation table's 'X' entries.
Candidates memorise class-to-class incompatibility in general terms but never learn that the segregation table must be read together with the segregation groups and that some class pairs are not segregated by the table at all.
What to do instead
Learn the four segregation terms with their physical meanings on a ship, then practise reading the segregation table for specific class pairs and cross-checking the segregation groups column in the DGL. Work through stowage scenarios on a container ship and a general cargo ship, stating the required separation in metres or compartments and justifying it.
Describing emergency response as 'call the emergency services' without referencing the EmS Guide schedule, the MFAG guide, or the shipboard emergency plan and reporting obligations.
Candidates treat emergency response as a soft topic and do not realise the exam expects specific document references and the sequence of notification to the coastal state and flag administration.
What to do instead
Learn the structure of the EmS Guide (fire schedules F, spillage schedules S) and the MFAG, and practise selecting the correct EmS schedule for a given UN number. Then write out an incident timeline: immediate onboard action, reference to the emergency plan, notification to the nearest coastal state and flag state, and the report content required under MARPOL and SOLAS.
Assuming limited quantity or excepted quantity provisions remove all marking, documentation and stowage duties, rather than applying the specific conditions and quantity limits for each regime.
The words 'limited' and 'excepted' suggest exemption from the Code, and candidates do not distinguish the two regimes, their package quantity limits, the reduced marking requirements and the surviving stowage and documentation obligations.
What to do instead
Build a comparison table with three columns: fully regulated, limited quantity, excepted quantity. For each, record the maximum quantity per inner packaging and per package, the marking required (limited quantity mark versus excepted quantity mark), whether a transport document is needed, and which stowage and segregation rules still apply. Test it on UN 1263 PAINT and a Class 9 substance.
Treating training as a one-off induction and being unable to state who is responsible for what, or which personnel need which type of training under the Code.
Candidates prepare for technical questions and skip the human-factors chapter, so they cannot distinguish shore-side functions from shipboard functions or explain the requirement for recorded, repeated training and a safety culture.
What to do instead
Map responsibilities by role: shipper, packer, forwarder, ship's master, designated dangerous goods officer, and the company's designated person ashore. For each, state the training category required, how competence is recorded, when refresher training is due, and give one example of a safety-culture failure such as an undeclared consignment. Practise explaining the consequences of inadequate training in a short written answer.