Control measure – Signs and symptoms of exposure

Control Measure Knowledge

Symptoms of exposure to hazardous materials can provide important information to responders on the type of hazard and level of risk. Symptoms will also provide responders with key information to determine the priorities in dealing with those who have potentially been exposed. Exposure to chemical hazardous materials will usually lead to the onset of symptoms much quicker than from exposure to biological or radiological materials. At an unknown event, this can be used as an indicator of the type of hazardous material involved.

Important information can be gained from the type of symptoms that are displayed, the number of people exposed and the time from exposure to symptoms becoming apparent.

Four routes of exposure can lead to symptoms developing:

  • Ingestion
  • Contact with skin or eyes
  • Inhalation
  • Injection or through cuts

The route through which exposure occurs can also be a significant factor on the speed and type of symptoms displayed. For example, exposure through a cut may mean that some hazardous substances get absorbed into the blood stream more quickly, enabling symptoms to develop rapidly.

Symptoms from hazardous materials will be either acute or chronic:

  • Acute: Substances whose effects develop quickly (usually within minutes to days) and worsen with increasing levels of exposure. These hazardous materials also have a level or threshold below which no harm is caused although, for example, in cases of highly toxic substance, this level can be very low.
  • Chronic: Substances whose effects develop after significant periods of time and usually following repeated exposure, for example, substances that can cause cancer.

Recognise, assess, react

The initial actions taken following a hazardous substances incident have a significant effect on the outcome for all involved. The following principle will help inform responders:

R – RECOGNISE the indicators of a hazardous substance incident

A – ASSESS the incident to inform an appropriate response strategy

R – REACT appropriately to reduce the risk of further harm

For more information on the appropriate action when visual indicators indicate a CBRN event refer to:

Visual indicators

If casualties are involved, physical symptoms can include:

  • Disorientation
  • Sweating
  • Twitching and convulsions
  • Airway irritation and breathing difficulties
  • Eye and skin irritation
  • Nausea and vomiting

If unprotected emergency responders observe incapacitated casualties without there being an explanation, they should not approach them, otherwise they may also become affected. However, emergency responders should attempt to determine what has occurred or is still happening, and report this to their control room.

For more information on visual indicators and appropriate actions refer to Initial Operational Response (IOR) to Incidents Suspected to Involve Hazardous Substances or CBRN Materials

Some CBRN materials will not lead to any immediate signs or symptoms but this does not preclude the dangers associated with their ongoing dispersal. It should also be borne in mind that some agents may travel considerable distances.

Strategic Actions

Tactical Actions