Understanding the Dangerous Goods Regulations (DGR) can be challenging – though IATA, the International Air Transport Association does a pretty good job of keeping it simple.  Sometimes compliance with the DGR can hinge on just one word.  Sometimes a “should” means something very different than a “Shall”.  The purpose of this brief article is to describe what it means when the IATA DGR uses terms such as:  “shall”, “must”, “should”, & “may”. (more…)