Three systems of hazard markings and classification are currently in use. The most common is the ADR (see below). You may also see GHS symbols (link). The third set (link) are now out of date but may still be seen on some packages.1. ADR transport pictograms and hazard classesPictogramClassHazard category 1.1Explosive, subclass 1.1Mass explosion hazard 1.2Explosive, subclass 1.2Projection hazard 1.3Explosive, subclass 1.3Fire hazard or minor projection hazard 1.4Explosive, subclass 1.4No significant hazard 1.5Explosive, subclass 1.5Very insensitive substances with mass explosion hazard 1.6Explosive, subclass 1.6Extremely insensitive articles with no mass explosion hazard 2.1Flammable gases 2.2Non-flammable, non-toxic gases 2.3Toxic gases 3Flammable liquids 4.1Flammable solids, self-reactive substances and solid desensitized explosives 4.2Substances liable to to spontaneous combustion 4.3Substances which, in contact with water, emit flammable gases 5.1Oxidizing substances 5.2Organic Peroxides 6.1Toxic substances 6.1Poison 6.2Infectious substances 7Radioactive materialCategory I Category II Category III Criticality safety index label 8Corrosive substances 9Miscellaneous dangerous substances and articles2. GHS pictograms and hazard classes Symbol: exploding bombPictogramHazard class and hazard category Section 2.1 Unstable explosivesExplosives of Divisions 1.1, 1.2, 1.3, 1.4Section 2.8 Self reactive substances and mixtures, Types A, BSection 2.15 Organic peroxides, Types A, B Symbol: flamePictogramHazard class and hazard category Section 2.2 Flammable gases, hazard category 1Section 2.3 Flammable aerosols, hazard categories 1, 2Section 2.6 Flammable liquids, hazard categories 1, 2, 3Section 2.7 Flammable solids, hazard categories 1, 2Section 2.8 Self-reactive substances and mixtures, Types B, C, D, E, FSection 2.9 Pyrophoric liquids, hazard category 1Section 2.10 Pyrophoric solids, hazard category 1Section 2.11 Self-heating substances and mixtures, hazard categories 1, 2Section 2.12 Substances and mixtures, which in contact with water, emit flammable gases, hazard categories 1, 2, 3Section 2.15 Organic peroxides, Types B, C, D, E, F Symbol: flame over circlePictogramHazard class and hazard category Section 2.4 Oxidising gases, hazard category 1Section 2.13 Oxidising liquids, hazard categories 1, 2, 3Section 2.14 Oxidising solids, hazard categories 1, 2, 3 Symbol: gas cylinderPictogramHazard class and hazard category Section 2.5 Gases under pressure: Compressed gases; Liquefied gases; Refrigerated liquefied gases;Dissolved gases Symbol: corrosionPictogramHazard class and hazard category Section 2.16 Corrosive to metals, hazard category 1Section 3.2 Skin corrosion, hazard categories 1A, 1B, 1CSection 3.3 Serious eye damage, hazard category 1 Symbol: skull and crossbonesPictogramHazard class and hazard category Section 3.1 Acute toxicity (oral, dermal, inhalation), hazard categories 1, 2, 3 Symbol: exclamation markPictogramHazard class and hazard category Section 3.1 Acute toxicity (oral, dermal, inhalation), hazard category 4Section 3.2 Skin irritation, hazard category 2Section 3.3 Eye irritation, hazard category 2Section 3.4 Skin sensitisation, hazard category 1Section 3.8 Specific Target Organ Toxicity — Single exposure, hazard category 3Respiratory tract irritationNarcotic effects Symbol: health hazardPictogramHazard class and hazard category Section 3.4 Respiratory sensitisation, hazard category 1Section 3.5 Germ cell mutagenicity, hazard categories 1A, 1B, 2Section 3.6 Carcinogenicity, hazard categories 1A, 1B, 2Section 3.7 Reproductive toxicity, hazard categories 1A, 1B, 2Section 3.8 Specific Target Organ Toxicity — Single exposure, hazard categories 1, 2Section 3.9 Specific Target Organ Toxicity — Repeated exposure, hazard categories 1, 2Section 3.10 Aspiration hazard, hazard category 1 Symbol: environmentPictogramHazard class and hazard category Section 4.1 Hazardous to the aquatic environment Acute hazard category 1 Chronic hazard categories 1, 23. Hazard symbols for chemicalsPictogramHazard class and hazard category O: Oxidizing T: ToxicT+: Very toxic C: Corrosive E: Explosive N: Dangerous for the environment Xn: HarmfulXi: Irritant F: FlammableF+: Extremely flammable The guidance contained in this section intended to serve as a general reminder of the risks that are sometimes encountered during the examination and sampling procedure and of the safety equipment that you should use and precautions that you should take.You must refer to the legislation and the guidance of your national administration for more information.