HAZMAT Class 4 Flammable Solids

Class 4 dangerous goods are solids that, under conditions encountered in transport, are readily combustible or may cause or contribute to fire through friction.

Primary Hazards

Class 4 substances may present fire or explosion hazards due to the following risks:

• May be ignited by heat, friction, sparks, or flames.
• May burn rapidly with flare burning effects.
• Powders, dusts, shavings, or cuttings may explode or burn with explosive violence.
• May reignite after fire is extinguished.
• May produce irritating, corrosive, and toxic gases.
• May ignite with contact with air or moisture.

In addition, contact with these substances may also cause severe burns to skin and eyes, and inhalation or ingestion of these substances may be toxic.

Divisions

Class 4 dangerous goods are subdivided into one of three divisions:

• Division 4.1 - Flammable Solids; Self-reactive Substances; Polymerizing Substances; and Desensitized Explosives
• Division 4.2 - Substances Liable to Spontaneous Combustion
• Division 4.3 - Substances Which, in Contact with Water, Emit Flammable Gases

Packing

Many Class 4 substances must be segregated during shipping. Specific packing instructions are listed in Section 4.2 - List of Dangerous Goods and can be found in Section 5.4. The packing instruction numbers are in the 400 range.

To learn more about IATA DGR visit our IATA DGR Refresher Online Training web page.