The section of the MSDS that explains what conditions, such as heat or shock, make the hazardous material unstable is

• A. Reactivity data
• B. First aid measures
• C. Exposure controls
• D. Storage and handling

Answer: (A)

Understanding when a hazardous material can become unstable is addressed by the reactivity data section of the MSDS. This part explains how stable the chemical is and what conditions can trigger reactions or decomposition—things like heat, shock, friction, moisture, or contact with incompatible substances. It may also note possible dangerous decomposition products that could form if those conditions occur. This information directly guides safe handling, storage, and emergency response by telling you which situations to avoid. The other sections cover how to treat people exposed to the material, how to control exposure, and general storage and handling procedures, but they do not specify the conditions that cause instability, which is why the reactivity data section is the best answer.