What defines a material as ocean shipping hazardous material?

A material is defined as an ocean shipping hazardous material primarily by its classification as hazardous according to the SOLAS (Safety of Life at Sea) standards. These standards serve to ensure the safety of maritime transport and protect the environment while at sea. The classification involves identifying certain properties of materials that could pose risks during shipping, such as flammability, toxicity, or reactivity.

While the IMDG (International Maritime Dangerous Goods) Code indeed classifies hazardous materials for sea transport and is closely related to SOLAS, referencing SOLAS standards highlights the broader regulatory context within which these materials are managed. This regulatory framework helps ensure that any material suspected of posing a danger in maritime environments is appropriately handled, marked, stowed, and declared, thus reinforcing maritime safety.

The other choices, such as requiring special markings or exceeding certain weights, are aspects that may relate to the handling and identification of hazardous materials but do not fundamentally define them under the required regulations for ocean shipping. In essence, the definition aligns most directly with the classification under SOLAS standards, making it a cornerstone of maritime safety regulations.