What indicates a chemical is capable of being infectious?

The ability of a chemical to be infectious primarily relates to how it can be transmitted from one host to another. When a chemical is described as easily transmitted, it suggests that the substance can spread effectively through various means, such as air, water, or direct contact with surfaces or individuals. This transmission capability is a hallmark of infectious agents, as it plays a crucial role in the propagation of diseases. An infectious agent, such as a virus or bacteria, can be passed from an infected host to a healthy individual, leading to potential outbreaks or spread of illness.

In contrast, the other options occupy different areas of concern regarding chemicals but do not specifically address their infectious nature. For instance, a recognizable odor may indicate the presence of a chemical but does not directly relate to its infectious capabilities. Similarly, harmful effects upon contact and respiratory issues can be characteristics of certain chemicals, yet they do not inherently denote that the chemical has the ability to comprise an infectious risk, which is fundamentally associated with the transmission aspect.