Hazardous Materials (Hazmat) Incidents – Aspects and Features


Your emergency response effort must consider the health hazards of a hazardous substance release. These hazards impact emergency responders, communities, and you.

In some cases, hazardous substances may irritate the skin or eyes, make it difficult to breathe, cause headaches and nausea, or result in other types of illness. Some hazardous substances can cause far more severe health effects, including:[1]

  • behavioral abnormalities,
  • cancer,
  • genetic mutations,
  • physiological malfunctions (e.g., reproductive impairment, kidney failure, etc.),
  • physical deformations, and
  • birth defects.

Hazardous Materials Exposure Pathways

The exposure pathway of a hazardous substance is an important consideration in determining emergency response actions. An exposure pathway refers to the way a person can come into contact with a hazardous substance.

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There are three basic exposure pathways: inhalation, ingestion, or direct contact. The degree or extent of exposure is determined by measuring the amount of the hazardous substance at the point of contact. Health and ecological hazards can result from such exposures. Common ways in which people can become exposed to hazardous substances include:[2]

Groundwater and Surface Water
Exposure will occur if people drink contaminated groundwater or surface water, accidentally ingest it while swimming, or if it comes into contact with their skin (e.g., in the shower, while swimming, etc.).

Soil, Sediment, Dust
People will be exposed to hazardous substances in soil, sediment, or dust if they accidentally ingest it (e.g., the contaminants land on their food), if they breathe it in (especially dust), or if their skin comes into direct contact. Because of their play habits, children are highly susceptible to exposure through these pathways.

When the hazardous substance takes the form of vapors or is absorbed by particulate matter, the simple act of breathing can expose people. In some cases, a person's skin can absorb a hazardous substance in vapor form, although inhalation is considered the greater threat.

Eating food that has been contaminated is another common exposure route. In some cases, food found on people's plates may be contaminated as a result of direct exposure to the hazardous substance. In other cases, food contamination can occur further down the food chain. For example, hazardous substances can collect in the fatty tissues of animals that ingest contaminated plants. The contamination can then be transferred to the animals' natural predators, and eventually, to people.


Table. Pipeline Hazardous Materials Exposure Hazards and Actions

The following quick reference table from the Emergency Response Guidebook (ERG) outlines pipeline hazardous materials exposure and health hazards:[3]

Product Type Vapors Exposure Health Hazards Actions
Refined Petroleum Products
(Gasoline, Diesel, or Jet Fuel)
Liquid Heavier than air • May release vapors which ARE highly flammable, unstable and can be dangerous if inhaled.

• Exposure may cause moderate irritation

• Vapors may cause dizziness and can displace oxygen in breathing air.

1. Avoid inhalation of any vapors and contact with the liquid, if possible.

2. Move to fresh air and avoid low or confined areas.

3. Seek medical attention if you are concerned about your health.

Crude Oil
Highly Volatile Liquids
[such as Propane, Butane, Propylene, Natural Gas Liquids (NGLs), and Liquefied Petroleum Gases (LPGs)]
Flammable Gases
Nitrogen (Inert) Initially heavier than air – will mix with air and dissipate • May release vapors which ARE NON-flammable.

• Vapors may cause dizziness and can displace oxygen in breathing air.



  1. EPA – Health and Ecological Hazards Caused by Hazardous Substances: http://www2.epa.gov/emergency-response/health-and-ecological-hazards-caused-hazardous-substances
  2. EPA – Possible Exposure Pathways During Emergencies: http://www2.epa.gov/emergency-response/possible-exposure-pathways-during-emergencies
  3. DOT – Pipeline and Hazardous Materials Safety Administration (PHMSA) – 2012 Emergency Response Guidebook (ERG): http://www.phmsa.dot.gov/hazmat/library/erg
  4. Image Source: http://www2.epa.gov/enforcement/waste-chemical-and-cleanup-enforcement#cleanup [Accessed March 30, 2014]