Marking and Labels on Containers for Dangerous Goods

4. 6. 2025

Introduction to Marking and Labeling of Dangerous Goods

Marking and labeling of containers for dangerous goods represents a fundamental pillar of chemical and logistics safety. In global transport, storage and handling of chemicals, gases, explosives and other hazardous materials, proper marking is essential for protecting human health, property and the environment. This system is not random — it is based on detailed international regulations (ADR, IMDG, GHS, CLP) and technical standards.

Purpose of marking and labeling:

  • Immediately and clearly inform about the nature of the container’s contents, its risks and handling requirements.
  • Ensure protection of workers, emergency services and the general public in case of an extraordinary event.
  • Ensure compliance with legal regulations (e.g. ADR, RID, IMDG, CLP), whose non-compliance can have serious legal and financial consequences.

What is marking used for in practice?

  • Hazard identification: Quick recognition of whether the container contents are flammable, toxic, corrosive, explosive or otherwise hazardous.
  • Safe handling: Provides instructions and warnings for proper handling, storage and transport.
  • Crisis management: Enables rapid and effective response by firefighters, rescue workers and environmental agencies in case of leakage, fire or accident.
  • Error prevention: Minimizes the risk of substance confusion, cross-contamination or inappropriate storage.

Legal Framework and Basic Standards

International and European Regulations

AbbreviationNameScope of Application
GHSGlobally Harmonized System of Classification and Labeling of Chemical Substances (UN)Basic framework for classification and marking of substances and mixtures
CLPRegulation (EC) No. 1272/2008 (Classification, Labelling and Packaging)European Union, implementation of GHS into EU law
ADREuropean Agreement concerning the International Carriage of Dangerous Goods by RoadRoad transport in Europe and adjacent countries
RIDRegulations concerning the International Carriage of Dangerous Goods by RailRail transport
IMDG CodeInternational Maritime Dangerous Goods CodeMaritime transport
IATA DGRInternational Air Transport Association Dangerous Goods RegulationsAir transport

Each legal standard determines detailed requirements for:

  • Classification of hazardous substances and mixtures (classes, UN numbers, official names, packing groups)
  • Method of marking and labeling, dimensions and placement of marks
  • Obligations of transport participants, training, documentation

Classification of Dangerous Goods — 9 Classes

All hazardous substances fall into one of the following classes (according to the UN “Orange Book”):

ClassNameExamplesKey Risk
1ExplosivesExplosives, pyrotechnicsExplosion, detonation
2GasesPropane, acetylene, oxygenFlammability, toxicity
3Flammable LiquidsGasoline, ethanol, paintsCombustion, vapors
4Flammable SolidsSulfur, phosphorusSelf-ignition
5Oxidizing SubstancesAmmonium nitrateOxidation, reaction
6Toxic/Infectious SubstancesCyanides, pesticidesPoisoning, infection
7Radioactive MaterialsIsotopes, uraniumRadiation
8CorrosivesSulfuric acidCorrosion, erosion
9Miscellaneous Hazardous SubstancesLithium batteries, asbestosVarious risks

Each class has assigned specific labels, placards and requirements for packaging or handling.

Key Elements of Marking and Labeling

UN Number

  • Four-digit code (e.g. UN 1203 for gasoline)
  • Mandatory on packaging, container and in transport documentation
  • Enables precise identification of the substance in the international database

Official Shipping Name (PSN — Proper Shipping Name)

  • Standardized name of the substance according to UN Model Regulations
  • Must be identical on all documents and markings

Packing Group (PG)

  • Determines the degree of hazard:
  • I – high risk
  • II – medium risk
  • III – lower risk
  • Marking directly on the packaging: e.g. “UN 4G/Y30/S/22/D/BAM1234”

Pictograms and Safety Labels

  • Diamond labels (100×100 mm) on individual items
  • Placards (250×250 mm) on outer walls of containers
  • Orange tables (400×300 mm) with UN number and hazard code on vehicles and containers
SymbolMeaningClass
Explosives1
Gases2
Flammable Liquids3
Corrosives8

Labels must be durable, clearly visible and must not be covered by other objects or soiled.

Difference Between Marking and Labeling

Labeling:

  • Placement of standardized labels containing pictograms, signal words, H- and P-statements
  • Used mainly on consumer and work packaging according to GHS/CLP

Marking:

  • Broader concept: includes labels and other mandatory information (UN number, safety marks — placards, official name, handling instructions)
  • Mandatory on transport containers, tanks, vehicles

Structure of Label According to GHS/CLP

Each label must contain these elements:

  1. Product name / identifiers
  2. Hazard pictograms (see above)
  3. Signal word (“Danger” / “Warning”)
  4. Standard H-statements (for example: H225 – Highly flammable liquid and vapors)
  5. P-statements (recommendations for safe handling, e.g. P210 – Keep away from heat)
  6. Supplier identification (name, address, phone)
  7. UN number and official shipping name (on transport packaging)

Table of Examples:

Label ElementDescriptionExample
Product NameChemical substance / mixtureAcetone
PictogramFlammability symbol
Signal WordDANGERDANGER
H-statementNature of HazardH225: Highly flammable liquid and vapors
P-statementPreventionP210: Keep away from heat and open flame
SupplierIdentificationChemCo Ltd., Prague, tel. 123 456 789

Types of Containers and Marking Requirements

ISO Containers

  • Most commonly 20′ and 40′ feet (ISO 668)
  • Must have fixed safety marks on both longer and shorter sides (min. 250×250 mm)
  • Orange tables with UN number (400×300 mm) on front and rear of vehicle transporting the container

Tank Containers

  • Additionally marked with tank code, maximum operating pressure and volume information
  • Special marking for pressurized gases, explosives, radioactive materials

Smaller Packages Inside Container

  • Each individual package must be labeled according to GHS/CLP and UN number

Specifics of ADR Marking

ADR — European Agreement on Road Transport

  • Marking of containers and vehicles is strictly standardized
  • Mandatory elements (summary):
ElementSizeLocationSpecifics
Orange Table400×300 mmFront and rear of vehicleReflective, fire resistance min. 15 min
Safety Placards250×250 mmBoth sides and both ends of containerCorresponding hazard inside
Identification Numbers100 mmOn orange tableUpper part — hazard code, lower — UN number
  • Exceptions: Some substances have different or supplementary marking (e.g. Class 7 — radioactive materials)

Practical Examples of Container Marking

Example 1: Transport of Gasoline (UN 1203, Class 3, PG II)

ElementLocationText/Symbol
Orange TableFront and rear of vehicle33 / 1203 (33 = highly flammable liquid, 1203 = gasoline)
Safety PlacardBoth side walls and both ends of containerFlame symbol, Class 3
Label on PackageEach canister insideGHS02, H225, P210, supplier identification

Example 2: Transport of Sulfuric Acid (UN 1830, Class 8, PG II)

ElementLocationText/Symbol
Orange TableFront and rear of vehicle80 / 1830
Safety PlacardBoth side walls and both ends of containerCorrosive symbol, Class 8
Label on PackageEach drum insideGHS05, H314, P280, supplier identification

Correct Application of Marking — Common Errors and Consequences

  • Errors in UN number or PSN: Can lead to substance confusion, inappropriate response in case of accident and legal penalties
  • Damaged or illegible labels: Inspection authorities may detain the shipment, impose a fine or stop operations
  • Missing signal word or pictogram: Occupational safety hazard, risk of injury
  • Incorrect label placement: Non-compliance with regulations, fine, possible deterioration of crisis response

Digitalization and Modern Trends

Electronic Safety Data Sheets and QR Codes

  • Modern labels contain QR or barcode that allows immediate access to current Safety Data Sheet (SDS)
  • Digitalization enables efficient chemical management, employee training, error minimization

Centralized Databases

  • SDS management in company databases, automatic updates and compliance monitoring with regulations

Online Training and E-learning

  • Mandatory ADR training, GHS/CLP for all employees handling hazardous substances

Ensuring Safety During Transport and Storage

AreaObligations and Recommendations
TrainingMandatory for drivers (ADR), handlers, warehouse workers
DocumentationADR transport document, written instructions for accidents, safety data sheets
Cargo SecuringPhysical security against shifting, leakage or damage
InspectionsRegular inspections of marking, label and document updates
Crisis PlanInternal procedures for leakage, fire, accident — all employees must be informed

Frequently Asked Questions (FAQ)

How often do labels need to be checked and possibly renewed?

  • At minimum before each transport, with each package handling and whenever the label is damaged.
  • If the substance composition changes or regulations are updated, the label must be updated immediately.

Who is responsible for correct container marking?

  • Both the shipper (manufacturer, distributor) and the carrier. Each link in the logistics chain has clearly defined obligations.

What are the penalties for violating regulations?

  • Fines up to millions of CZK, suspension of operations, criminal liability in case of injury to health or environment.

Related Terms

  • Safety Data Sheet (SDS/MSDS): Detailed document on chemical substance, risks, first aid, fire measures, waste disposal
  • Hazardous Waste: Waste with properties of hazardous substance, requires special marking and disposal
  • Hazard Class: Classification according to main risk (see above)
  • UN Number: International identifier of hazardous substance

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