Which is the best example of secondary contamination?

Secondary contamination refers to the process by which a person or object becomes contaminated as a result of contact with another contaminated source or individual, rather than being contaminated directly by the primary hazardous material itself.

In this context, when considering the scenarios provided, encountering runoff from firefighting operations on an ignited material exemplifies secondary contamination. This situation occurs when hazardous materials are carried away by water or other substances used during firefighting efforts. The runoff can contain harmful contaminants that can adhere to individuals, equipment, or the surrounding environment, leading to additional exposure that is not a direct result of the initial hazardous incident.

Handling an unwashed protective suit might suggest a risk of contamination, but it is primarily about potential exposure from residual chemicals rather than new contamination introduced from an external source. Touching a contaminated surface is a more straightforward case of direct contamination rather than secondary. Interacting with a contaminated patient involves direct contact with a hazardous material, which also does not fit the definition of secondary contamination.

Therefore, the runoff from firefighting serves as a clear illustration of secondary contamination, highlighting the potential for hazardous materials to spread through indirect means, necessitating careful management and decontamination procedures.