Contact with a chemical, physical or biological agent is referred to as:

Contact with a chemical, physical, or biological agent is referred to as exposure because it specifically denotes the situation where an individual comes into contact with a potentially harmful substance or agent. This can occur through inhalation, ingestion, or dermal contact. Understanding the concept of exposure is crucial in the context of hazardous waste operations and emergency response because it highlights the potential risks involved in handling hazardous materials.

Threshold Limit Value (TLV) refers to guidelines regarding exposure limits for workplace conditions, which help define safe levels of exposure over a typical workday. Immediately Dangerous to Life or Health (IDLH) describes situations or conditions that pose an immediate threat to life or health, requiring urgent action. Concentration indicates the amount of a substance present in a given volume or mass, but it does not define the act of contact itself. Thus, exposure is the most appropriate term for the contact with harmful agents.