These are substances or articles that pose an explosive hazard.  There are six sub groups:

​

1.1 - Mass explosion hazard

1.2 - Projectile hazard

1.3 - Fire hazard, minor explosion or minor projection hazard

1.4 - Minimal hazard

1.5 - Blasting agents

1.6 - Very insensitive detonating articles

​

When carrying explosives, the NEQ (Net Explosive Quantity) is included in the transport document, separate to the gross weight. 

A compatibility group is also included, designated by a letter to each item.  This details which items can be transported together.

​

Examples of Class 1 substances include:

​

UN0014 - Cartridges for weapons, blank or cartridges, small arms, blank or cartridges for tools - 1.4S (tunnel code E)

UN0048 - Charges, demolition - 1.1D (tunnel code B1000C)

UN0222 - Ammonium Nitrate - 1.1D (tunnel code B1000C)