The Phases of Contamination

In the event of a chemical incident, contamination has three phases [6]:

Primary Phase

Primary contamination is from the incident and can only be minimised by scene management, for example by safety measures, personal protective equipment (PPE) and handling plans etc.

Secondary Phase

Secondary contamination is from contaminated people leaving the scene and taking the chemical with them, and may occur from the exhalation of patients with certain poisonings, such as cyanide [7].

Tertiary Phase

Tertiary contamination means that it has spread to the environment, including air- and water-borne spread.