The presence of hazardous materials can always be detected by the sense of smell?

In the framework of the Incident Command System (ICS), the inability to detect hazardous materials through smell underscores the importance of comprehensive hazard assessment and the use of appropriate detection equipment. Incident commanders and emergency responders must rely on more than just sensory perception to identify and manage hazardous materials. For instance, in a chemical spill scenario, HazMat teams use specialized equipment to detect and identify chemicals that are not discernible by smell.

From the perspective of other personnel involved in emergency response, such as firefighters, medical staff, and law enforcement, the unreliability of smell in detecting hazardous materials necessitates strict adherence to safety procedures and the use of personal protective equipment (PPE). These professionals understand that hazardous substances can be present without any sensory indication, making environments potentially more dangerous than they appear.

Source: https://training.fema.gov/is/courseoverview.aspx?code=is-5.a&lang=en