Dangerous Goods (DG) or Hazardous Materials (Hazmat) are IMO cargo classified into 9 classes.
Classes 3, 4, 5.1, 6.1 and 8 have been divided into three packaging groups (PG).
The Packaging Group (PG) indicates the degree of risk within the classes and specifies the standard of packaging.
PG I denotes high risk and therefore requires the highest standard of packaging;
PG II denotes medium risk;
PG III denotes low risk.
Important Note: The IMDG code uses the term packaging group rather than packing group.