Dangerous goods are “articles or substances which are capable of posing a risk to health, safety, property or the environment” and which are covered under the IATA regulations. IATA DGR Appendix A.
 
Many everyday items and substances can be dangerous when transported by air.
Due to the variations in temperature and pressure during a flight, some of these items may leak or break, generating toxic fumes or possibly starting a fire.

Employees who may come into contact with dangerous goods need to be aware of the nature of such goods, their potential for causing incidents and accidents and how they should be dealt with.
 
In addition anyone processing Passengers or performing security checks on them need to have a high level of awareness and to be vigilant regarding the potential for passengers to unknowingly carry Dangerous Goods on their person or to place in the personal baggage in the aircraft cargo compartment.