From her work with customers, Pratibha already knew quite a bit about DNH cargo. She knew that the term “DNH” referred very specifically to substances that could be dangerous when they were shipped: chemicals, liquids or solids that could easily catch fire, or substances that would react badly with water. Because of a concern for safety — both the safety of the captain and crew carrying the DNH cargo and also the safety of the overall ocean environment — there were very strict rules for shippers who carried DNH cargo from place to place.

Rules about DNH cargo had been created by an organization called the International Maritime Organization (IMO). The IMO helped make sure shippers around the world all followed the same safety rules both at sea and when they were in port. In addition, each country had established its own rules about shipping and DNH cargo. In the United States, for instance, the U.S. Department of Transportation set the rules about dangerous cargo.

Pratibha knew that there were many different kinds or “classes” of DNH cargo. There were different rules for each class of cargo. The rules were based on how dangerous the cargo was, whether it was a liquid, a solid, or a gas, and what harm the cargo could cause. For instance, shippers were required to carry cargo containers of some highly flammable liquids above the deck of the ship; that way, if there was a fire aboard ship, the flammable cargo could be pushed overboard before it exploded. Pratibha knew that everyone wanted to treat DNH cargo safely and avoid accidents. Her job was to help by making sure all the paperwork which described this cargo arrived on time to the people who needed to see it to know how to deal with the cargo.