What odor might suggest the presence of a hazardous material?

The presence of a hazardous material can often be indicated by certain distinct odors that are not typical or natural in the environment. The smell of burnt rubber, for example, is commonly associated with hazardous materials, particularly those that may be part of industrial processes or accidents. This odor can signal the combustion of materials that release toxic fumes, which require immediate assessment and caution.

In contrast, the other options such as freshly cut grass, baking bread, and cut onions are benign and typically do not suggest hazardous situations. These odors are associated with normal, everyday activities and do not indicate the presence of any harmful substances. Understanding these associations helps individuals accurately identify potential risks related to hazardous materials in various environments.