The IMDG Code (International Maritime Dangerous Goods Code) is the global standard for shipping hazardous materials by sea, mandatory under SOLAS. It defines 9 hazard classes, each with distinct packaging, labeling, documentation, segregation, and stowage requirements. For exporters shipping from China, understanding which class your cargo falls into is the first step toward a compliant shipment. Misclassification is the single most common cause of DG cargo rejection at Chinese ports.
Class 1 Explosives
Sub-divisions: 1.1 (mass explosion hazard), 1.2 (projection hazard), 1.3 (fire hazard), 1.4 (minor hazard), 1.5 (insensitive), 1.6 (extremely insensitive).
Common UN numbers: UN0012 (cartridges, small arms), UN0161 (smokeless powder), UN0336 (fireworks), UN0082 (blasting explosive, Type B).
Product examples: Fireworks, industrial blasting explosives, ammunition, airbag inflators, detonators, signal flares.
Key requirements: Class 1 is the most tightly controlled DG class. In China, explosive exports require licensing from the Ministry of Public Security and the State Administration of Work Safety, in addition to standard DG export procedures. Only specialized licensed ports handle Class 1 (primarily Beihai and certain designated terminals at Shanghai). At Qingdao, Class 1.4S (fireworks) is handled seasonally. Great Hensen does not currently handle Class 1 shipments due to the specialized licensing and port infrastructure required. We recommend working with a Class 1-specialized forwarder with direct explosives licensing.
Class 2 Gases
Sub-divisions: 2.1 (flammable gases), 2.2 (non-flammable/non-toxic), 2.3 (toxic gases). Aerosols ship under UN1950 with SP63 provisions.
Common UN numbers: UN1978 (propane), UN1011 (butane), UN1001 (acetylene), UN1072 (oxygen), UN1066 (nitrogen), UN1013 (CO2), UN1005 (ammonia, anhydrous), UN1950 (aerosols), UN1078/UN3159 (refrigerant gases).
Product examples: LPG cylinders, welding gases, medical oxygen, helium, aerosol sprays, refrigerant gases (R-134a, R-410A), chlorine for water treatment.
Packaging: UN-certified pressure receptacles (ISO 9809 steel/aluminum cylinders) with valid hydrostatic test certificates (typically 5-10 year validity). Valve protection caps mandatory. Aerosols must withstand 55°C without bursting, inner receptacles max 1,000 mL.
Carrier acceptance: Class 2.1 and 2.2 broadly accepted by MSK, HPL, MSC, COSCO, HMM, OOCL, EMC, YML, CMA CGM with advance booking (5-7 days). Class 2.3 (toxic gases) restricted to MSK, MSC, and COSCO on specific routes. UN1950 aerosols widely accepted.
Great Hensen capability: We handle all Class 2 sub-divisions, including cylinder inspection coordination, DG packaging certificate (危包证), and carrier DG booking for gases. Regular refrigerant gas exports from Qingdao to Middle East and Africa.
Class 3 Flammable Liquids
Packing groups: PG I (flash point < -18°C, bp ≤35°C), PG II (flash point < 23°C), PG III (flash point 23-60°C). PG determines packaging robustness and air freight eligibility.
Common UN numbers: UN1170 (ethanol), UN1090 (acetone), UN1203 (gasoline), UN1219 (isopropanol), UN1263 (paint/paint-related materials — highest-volume UN from China), UN1866 (resin solution), UN1993 (flammable liquid N.O.S.), UN1133 (adhesives), UN1210 (printing ink), UN1266 (perfumery products).
Product examples: Industrial solvents, paints and coatings, printing inks, adhesives, perfumes, essential oils, hand sanitizer, cleaning solvents, resin solutions, nail polish.
Packaging: UN-approved jerricans (1H1/3H1, up to 25L), steel drums (1A1/1A2, up to 220L), IBCs (31HA1, 1,000L+ for PG II/III only), ISO tank containers (T11/T14, 20,000L+). Inner + outer combination packaging with absorbent material for glass/plastic inner containers.
Carrier acceptance: PG II and PG III accepted by all 9 major carriers for sea freight. PG I restricted: MSK and MSC accept, HPL/OOCL/EMC case-by-case, HMM/EMC do not accept PG I. Air freight: PG II/III on cargo-only aircraft with quantity limits (5L PG II, 60L PG III per inner packaging).
Great Hensen capability: Class 3 is our highest-volume DG class. We handle everything from single drums of paint to ISO tanks of solvents, with flash point verification, UN packaging procurement, and carrier booking across all three ports.
Class 4 Flammable Solids
Sub-divisions: 4.1 (flammable solids, self-reactive, desensitized explosives), 4.2 (spontaneous combustion), 4.3 (dangerous when wet — emits flammable gas on water contact).
Common UN numbers: UN1350 (sulfur), UN1944/UN1945 (matches), UN1334 (naphthalene), UN1361/UN1362 (charcoal/activated carbon), UN1402 (calcium carbide), UN1428 (sodium), UN1396 (aluminum powder, uncoated), UN1436 (zinc powder/dust), UN3175 (solids containing flammable liquid).
Product examples: Sulfur (China is the world's largest producer/exporter), calcium carbide (major Chinese export, ~1M tons/year), metal powders (aluminum, magnesium, zinc), matches, celluloid, mothballs, sodium/potassium metal, fish meal (unstabilized).
Packaging: 4.1: UN-approved fiberboard boxes, steel/plastic drums. 4.2: hermetically sealed packaging with nitrogen/inert gas blanket. 4.3: hermetically sealed steel drums with desiccant packs, nitrogen purge for calcium carbide; container must be absolutely dry; on-deck stowage mandatory.
Carrier acceptance: 4.1 broadly accepted by all carriers. 4.2 accepted by MSK, MSC, COSCO, CMA CGM; HPL/YML case-by-case; HMM/OOCL/EMC generally do not accept. 4.3 most restricted: only MSK, MSC, COSCO accept, and only on specific routes.
Great Hensen capability: We handle all Class 4 sub-divisions, including moisture-sensitive 4.3 shipments. Regular calcium carbide exports from Shandong to Europe on MSK/MSC. On-site container inspection for water ingress before loading 4.3 cargo.
Class 5 Oxidizing Substances & Organic Peroxides
Sub-divisions: 5.1 (oxidizing substances that release oxygen and intensify fire), 5.2 (organic peroxides — thermally unstable, many require temperature-controlled transport).
Common UN numbers: UN2014/UN2015/UN2984 (hydrogen peroxide, concentration-dependent), UN1942 (ammonium nitrate), UN1486 (potassium nitrate), UN1495 (sodium chlorate), UN1748/UN2208 (calcium hypochlorite / pool chlorine), UN3104/UN3105 (organic peroxides, benzoyl peroxide, MEKP).
Product examples: Hydrogen peroxide (China major producer), ammonium nitrate fertilizer, pool chlorine/bleaching powder, potassium/sodium nitrate for glass and fireworks, MEKP for composite curing.
Packaging: 5.1: UN-approved drums or IBCs with material compatibility verification (stainless steel or HDPE for peroxide; never carbon steel or copper). 5.2: temperature-controlled containers (reefers) if SADT ≤50°C; dual-redundant reefer units with remote monitoring.
Segregation: Class 5.1 must be "separated from" (min 3m) Class 3, 4.1, and 8. Class 5.2 must be in dedicated containers, no co-loading with any other DG class. Never mix oxidizers with combustibles in the same container.
Carrier acceptance: 5.1 PG II/III broadly accepted by all carriers. 5.1 PG I restricted to MSK and MSC. 5.2 organic peroxides: only MSK, MSC, COSCO, and CMA CGM accept on a case-by-case basis; other carriers do not accept. Air freight heavily restricted for both sub-divisions.
Great Hensen capability: We handle both 5.1 and 5.2 shipments, including temperature-controlled organic peroxide transport from Qingdao with GPS-tracked reefers. Regular calcium hypochlorite exports from Shandong chemical plants.
Class 6 Toxic & Infectious Substances
Sub-divisions: 6.1 (toxic substances, graded by acute toxicity LD50/LC50 into PG I, II, III), 6.2 (infectious substances — Category A UN2814/UN2900, Category B UN3373).
Common UN numbers: UN2783/UN3017 (organophosphorus pesticides), UN2757 (carbamate pesticides), UN1689 (sodium cyanide), UN1561 (arsenic trioxide), UN2809 (mercury), UN1671 (phenol), UN2814 (infectious substance, affecting humans), UN3373 (biological substance, Category B), UN3291 (clinical waste).
Product examples: Pesticides (China is world's largest exporter, 1.5M+ tons/year), cyanides for gold mining, arsenic compounds, mercury, phenol/carbolic acid, medical diagnostic specimens, clinical waste.
Packaging: 6.1: double leak-proof packaging with absorbent inner layer; PG I requires metal inner containers. 6.2: triple packaging (P620 for Category A: 9m drop test, puncture test, pressure differential; P650 for Category B: 1.2m drop test). Dry ice refrigerant must allow CO2 venting.
Carrier acceptance: 6.1 PG II/III broadly accepted. 6.1 PG I restricted to MSK, MSC, COSCO case-by-case. 6.2 Category B (UN3373) well accepted. 6.2 Category A (UN2814/UN2900) only MSK, MSC, COSCO, CMA CGM case-by-case.
Special China controls: Sodium/potassium cyanide requires MOFCOM Dangerous Chemicals Export License. Mercury subject to Minamata Convention restrictions. Pesticides may need Ministry of Agriculture Export Notification.
Great Hensen capability: We handle 6.1 PG II/III routinely, especially pesticides from Shandong's agrochemical cluster. 6.1 PG I and 6.2 Category A on a case-by-case basis with additional lead time for regulatory approvals.
Class 7 Radioactive Material
No packing groups: Class 7 uses A1/A2 activity limits, Transport Index (TI), and packaging type (Excepted, Industrial IP-1/2/3, Type A, Type B) instead of the PG system.
Common UN numbers: UN2915 (radioactive material, Type A package, non-special form), UN2916 (Type B package), UN2911 (instruments/articles), UN2912/UN2913 (LSA-I/LSA-II, NORM), UN3332 (radioactive material, Type A, special form).
Product examples: Medical isotopes (I-131, Tc-99m generators, Lu-177), industrial radiography sources (Ir-192, Co-60), density/level gauges (Cs-137, Am-241), smoke detectors (Am-241, exempted), NORM-contaminated oil/gas equipment.
Packaging: Type A must survive normal transport conditions (water spray, drop, stacking, penetration tests). Type B(U)/B(M) must survive severe accident conditions (9m drop, 800°C fire 30min, 15m water immersion). CAEA-certified packaging required in China.
Carrier acceptance: Most restricted of all DG classes. Excepted packages: accepted by all carriers. Type A (LSA/SCO): only MSK, MSC, COSCO, CMA CGM case-by-case. Type B: generally only COSCO with limited acceptance. Most carriers do not accept radioactive materials beyond excepted packages.
China export controls: CAEA (China Atomic Energy Authority) export license required (2-4 weeks for routine shipments, 3-6 months for Type B). Exporter must be CAEA-registered. Destination country import license required before loading. Dual-use controls may apply.
Great Hensen capability: We coordinate Class 7 shipments with CAEA-licensed shippers, handling the regulatory chain from export license through carrier booking. Medical isotope air freight via PEK/PVG on IATA-certified carriers.
Class 8 Corrosives
Packing groups: PG I (full skin destruction within 3 min), PG II (3-60 min), PG III (4-14 days or corrodes steel/aluminum >6.25mm/year at 55°C).
Common UN numbers: UN1830 (sulfuric acid), UN1789 (hydrochloric acid), UN2031 (nitric acid), UN1805 (phosphoric acid), UN1790 (hydrofluoric acid), UN1823/UN1824 (sodium hydroxide solid/solution), UN1813/UN1814 (potassium hydroxide), UN2796 (battery acid), UN1791 (sodium hypochlorite), UN1760 (corrosive liquid N.O.S.).
Product examples: Sulfuric acid (China's single highest-volume DG product, 90M+ tons/year), caustic soda (world's largest producer), phosphoric acid (top exporter), battery electrolyte, bleach, industrial cleaning chemicals, descaling agents.
Packaging: Material compatibility is critical: sulfuric acid corrodes carbon steel, hydrofluoric acid dissolves glass, nitric acid attacks most plastics. UN-approved plastic jerricans (1H1), steel drums with corrosion-resistant linings, IBCs, ISO tanks. Orientation arrows (ISO 780) mandatory on all liquid corrosive packages.
Carrier acceptance: Class 8 has the most carrier-friendly profile. All 9 major carriers accept all three packing groups for sea freight. Air freight: PG II/III accepted on cargo aircraft with quantity limits; PG I generally prohibited on passenger aircraft.
Segregation: Acids and alkalis must never ship in the same container. Separate from Class 5.1 (oxidizers), Class 6.1 (toxic liquids), and foodstuffs.
Great Hensen capability: Class 8 is our second highest-volume DG class. We handle the full range from ISO tanks of sulfuric acid to bags of caustic soda flakes, with material-compatible packaging procurement and triple-port options (Qingdao, Shanghai, Tianjin).
Class 9 Miscellaneous Dangerous Goods
Key sub-categories (no uniform PG system): Lithium batteries (UN3480/UN3481/UN3536), environmentally hazardous substances (UN3077/UN3082), dry ice (UN1845), elevated temperature liquids (UN3257), magnetized material (UN2807, air only), asbestos (UN2212/UN2590), GMOs (UN3245).
Common UN numbers: UN3536 (lithium batteries installed in cargo transport unit — containerized BESS), UN3480 (lithium-ion batteries, standalone), UN3481 (lithium-ion batteries packed with equipment), UN3171 (battery-powered vehicles), UN3077/UN3082 (environmentally hazardous solid/liquid), UN1845 (dry ice).
Product examples: Containerized BESS (our core specialty), EV batteries, power tool batteries, dry ice for cold chain, hot bitumen, rare earth magnets (air freight), consumer smoke detectors, genetically modified microorganisms for research.
UN3536 / SP389: Effective January 2023 under IMDG Amendment 41-22. SP389 provides specific provisions for large-format BESS: batteries must be securely installed, BMS must prevent overcharge/discharge, short-circuit protection integral, ventilation prevents hazardous atmosphere accumulation, QMS-manufactured. Read our full UN3536 guide →
Packaging: UN3480: UN-approved packaging, terminals short-circuit protected, shock-absorbent cushioning, SoC ≤30% (IMDG SP384). UN3536: container IS the packaging, CSC plate must be valid, DC disconnects accessible from outside, DG placards on all four sides, BESS at 30-50% SoC. UN3077/UN3082: standard UN packaging with environmental hazard label.
Carrier acceptance: UN3536 accepted by MSK, MSC, COSCO; HPL and CMA CGM case-by-case; EMC does not accept. UN3480 increasingly restricted in 2025-2026: MSK, HPL, MSC, CMA CGM accept with advance booking; COSCO, HMM, OOCL, EMC, YML restrict. UN3481 and UN3077/UN3082 broadly accepted.
Great Hensen capability: UN3536 is our core DG competency — 1,000+ TEU of containerized BESS shipped from Qingdao to Europe, Middle East, and Africa with zero incidents. Full SP389 compliance audit, DG packaging certificate in 3 working days, and pre-loading BMS/SoC verification. Read our UN3536 case study →
How to Ship DG from China: General 5-Step Process
Every DG shipment from China follows the same five-stage workflow, regardless of class. Lead times vary by class, packing group, and carrier policy, but the process structure is consistent:
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Classification and MSDS Review (1-2 working days)
Obtain a GHS-compliant MSDS from the manufacturer. Confirm the correct UN number, IMDG class, sub-division, packing group, and any special provisions. For dual-hazard substances (e.g., flammable + toxic), determine the primary hazard per IMDG precedence rules. MSDS must be current (typically within 3 years). This step is critical — wrong classification causes cargo rejection, port delays, and potential fines.
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UN-Certified Packaging and DG Packaging Certificate (危包证) (1-3 working days for existing cert; 5-10 for new)
Procure packaging that meets UN performance standards for your class and packing group. The packaging must carry visible UN specification markings. An authorized Chinese inspection body (CIQ/CCIC) issues the DG Packaging Certificate confirming the packaging meets UN standards. For new products or packaging types, allow 5-10 working days for testing and certification. At Great Hensen, we manage this process end to end.
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Carrier DG Booking (5-7 working days before vessel cut-off)
Submit DG cargo details to the carrier: UN number, class, packing group, number/type of packages, total weight, stowage category, and any special requirements. Carrier DG acceptance varies by class, sub-division, and route. We match your cargo to the right carrier based on your destination and transit time requirements. Some classes (2.3, 4.3, 5.2, 7) require longer lead times for carrier approval.
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Maritime DG Declaration and Port Filing (24-48 hours before loading)
File the Maritime Dangerous Goods Declaration with the local Maritime Safety Administration (MSA, 海事局), citing the correct UN number, class, packing group, and vessel/voyage details. Simultaneously register the DG shipment with the port authority. Qingdao Port's DG acceptance process takes 1-2 working days. Shanghai's higher volume means 2-3 working days.
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Container Stuffing and Loading Supervision (1 working day)
Load cargo under DG supervision: verify packaging integrity, apply DG placards on all four sides of the container (250mm x 250mm), check segregation compliance, secure cargo against movement, and document the loading with photos. For temperature-controlled shipments (5.2, certain pharmaceuticals), verify reefer settings and redundancy. Container is then transferred to the DG yard for vessel loading.
Typical end-to-end timeline: 10-14 working days from cargo ready at factory to vessel sailing, assuming existing DG packaging certificates and standard-class DG. Add 1-2 weeks for new packaging certification, 2-4 weeks for CAEA licensing (Class 7), and 3-7 days for restricted sub-division carrier approvals.
Frequently Asked Questions
Do I need a DG Packaging Certificate (危包证) for every DG shipment from China?
Yes. For sea freight from China, a valid DG Packaging Certificate issued by an authorized inspection body (CIQ/CCIC) is mandatory for all dangerous goods shipments. The certificate confirms the packaging meets UN performance standards for the specific class and packing group. The certificate has a validity period (typically 1 year for the packaging design type) and must be current at the time of shipment. Limited Quantity (LQ) shipments have reduced packaging requirements but still need basic UN compliance. We manage the 危包证 process for all our DG clients.
What is the difference between a packing group and a hazard class?
The hazard class (1-9) defines the TYPE of danger (flammability, toxicity, corrosion, etc.). The packing group (PG I, II, or III) defines the DEGREE of danger within that class. PG I = high danger (most stringent packaging and handling), PG II = medium danger, PG III = low danger. For example, sulfuric acid above 51% is Class 8 PG I (causes full skin destruction within 3 minutes), while household bleach may be Class 8 PG III (less aggressive corrosion). The packing group directly determines packaging performance requirements, carrier acceptance, and whether air freight is permitted. Classes 1, 2, 7, and some Class 9 sub-categories do not use the PG system.
Can I ship multiple DG classes in one container?
Only if the IMDG segregation table permits it. The segregation rules are non-negotiable: some classes must never share a container (e.g., Class 8 acids with Class 8 alkalis, Class 5.1 oxidizers with Class 3 flammables). Others require "separated from" stowage (minimum 3 meters or different compartments). Class 5.2 organic peroxides generally must ship in dedicated containers with no co-loading at all. Before booking, we verify segregation using the IMDG segregation table and confirm that all items in the consignment are compatible. Non-compliance can result in container rejection and port blacklisting.
What happens if my DG cargo is misdeclared as non-DG?
Misdeclaration is the most serious violation in container shipping. Consequences include: container rejection at the port of loading (cargo does not sail), fines from the carrier (typically USD 10,000-50,000 per container), vessel delay penalties charged to the shipper, customs investigation and potential export privilege suspension in China, port authority blacklisting, criminal liability if the misdeclaration causes a fire or casualty at sea, and P&I Club insurance voidance. In 2025, several carriers introduced AI-powered cargo screening that cross-references the commodity description against DG databases, making misdeclaration harder to get away with. The cost of proper DG compliance is a fraction of the cost of getting caught.
Which classes can Great Hensen ship from Qingdao, and which are most common?
We handle Class 2 through Class 9 by sea freight from Qingdao (primary), Shanghai, and Tianjin ports. Our highest-volume classes by TEU: Class 3 (flammable liquids — paints, solvents, chemicals), Class 8 (corrosives — acids, caustic soda), and Class 9 (UN3536 BESS, our core specialty). Class 1 (explosives) we do not handle due to specialized licensing and port infrastructure requirements. Class 7 (radioactive) we handle on a case-by-case basis coordinating with CAEA-licensed shippers. For DG air freight, we focus on Class 9 (UN3481, dry ice) and limited Class 3/8 PG III shipments via IATA-certified carriers from Qingdao Liuting (TAO) and Shanghai Pudong (PVG).