Which of the following is a sign of a potential chemical hazard?

• A. Liquid spills
• B. Labeled containers
• C. Unlabeled containers
• D. All containers are sealed

Answer: (C)

The key safety idea here is that you must be able to identify every chemical you work with. An unlabeled container hides the identity and hazards of its contents, making it impossible to know what precautions, handling, or PPE are needed. This lack of information is itself a warning sign of potential chemical hazards because you could be exposed to something dangerous without realizing it, use incompatible substances together, or fail to follow proper spill and emergency procedures. Labels provide essential details like the chemical name, hazards, and instructions, which guide safe storage, use, and response.

Having labeled containers is the opposite of a hazard sign—they communicate what each substance is and what risks it carries. Sealed containers help contain a substance and reduce exposure, which is good practice, but they do not tell you what the substance is or its hazards. A liquid spill clearly shows that a hazard event has occurred, but the core issue for recognizing a potential hazard is whether you can identify the chemical in the first place.