Which of the following are major categories of hazardous materials encountered during sampling work?

The selection of corrosive materials, poisonous gases, and toxics as major categories of hazardous materials during sampling work is accurate because these categories encompass a wide range of substances that pose significant health and safety risks. Corrosive materials can damage living tissues or materials upon contact, making them a serious concern for workers handling them during sampling processes. Poisonous gases can be harmful or lethal when inhaled, presenting an immediate danger in confined spaces or during field sampling in various environments.

Toxics encompass a broad category of hazardous substances that can adversely affect health upon exposure, whether through inhalation, skin contact, or ingestion. This combination of hazards reflects the diverse dangers that professionals may face when conducting sampling in industrial, environmental, or laboratory settings.

In contrast, the other options include categories that, while important, do not collectively represent the primary hazards encountered as clearly as option C does. For instance, flammable materials and chemical wastes address specific risks but do not cover the range of health impacts associated with corrosives and toxic substances. Similarly, while biohazardous materials and radiological waste are significant, they focus on narrower areas of hazard compared to the comprehensive nature of the selected categories.