9-1-1; What Is Your Emergency?

Wednesday, April 1, 2009

Hazardous Materials Incidents

Article taken from Public Safety Communications Magazine December 2005
Written by Bob Smith

Incidents involving hazardous materials (HAZMATs) generate some of the most complex calls today's public safety industry personnel handle. The complexities arise from the logistics involved in a typical response and operation: multiple units from multiple disciplines, functioning on a scene that may expand and contract as the weather changes.

HAZMATs may present a fire hazard, an explosion threat, a chemical-gas threat or other risks to those in the area. With this in mind, it is important during the calltaking phase for telecommunicators to ask specific questions regarding the potential for HAZMATs that may be present. Confinement and containment are the first lines of defense in minimizing risk to both life and the environment during the early stages of a HAZMAT event. Both natural and synthetic methods can be used to limit the release of HAZMATs.

If the incident is taking place in a building, the telecommunicator should attempt to obtain information from the caller about the contents of the building and its surrounding area. If the caller is knowledgeable, the telecommunicator should ask if any materials in or around the building could be considered hazardous.

Asking about the type of business in the building can indicate the presence of HAZMATs. Manufacturing plants typically house flammable liquids, cleaning fluids, oils, fuels and other materials that can pose significant hazards. Even retail stores can have HAZMATs on the premises. All this information must be conveyed to responding units.

The caller should be directed to meet the responders and point out the location and nature of stored hazardous materials, if safe to do so.

Identification Placards

One method to determine the identity of a substance is a placard. Federal law requires that, when hazardous materials (more that a certain quantity) are being transported, identification placards be displayed on the vehicle. These placards have an identification number for the material and are color-coded for easy reference.

If possible, ask the caller what the placard looks like and determine the number on the placard. Make certain the caller is not put in danger in order to read the placard!

The number and color combination on the placard can be looked up in the North American Emergency Response Guidebook (NAERG). The NAERG is published by the United States Department of Transportation and is used as a reference during HAZMAT calls. It contains HAZMAT information categorized by material name and reference number, plus guidelines that explain how to handle the substance, including isolation distances, if necessary. Your agency should have a copy of this guide on hand at each console. Using the NAERG, a telecommunicator can determine the exact substance and the hazards that are present. All this information must be relayed to the responding units as soon as possible.

Classes of Materials

The United States Department of Transportation categorizes HAZMATs into nine classes. They are:
  • Class 1 - Explosives
  • Class 2 - Gases
  • Class 3 - Flammable liquids
  • Class 4 - Flammable solids
  • Class 5 - Oxidizers and organic peroxides
  • Class 6 - Poisonous materials
  • Class 7 - Radioactive materials
  • Class 8 - Corrosive materials
  • Class 9 - Miscellaneous

On the Scene

Similar to the A, B, C or D designation given to the sides of a structure, HAZMAT incidents are also arranged by geographical reference. Called "zones," they are determined by the area and the substance involved. The zones are formed in the shape of concentric circles that spread out from the location of the material involved.

The "hot zone" is the area immediately surrounding a HAZMAT incident and the involved material itself. The hot zone extends far enough from the material to prevent further exposure to and adverse effects on personnel outside the zone.

The "warm zone" begins where the hot zone stops and spreads away from the area immediately surrounding the material itself. This area is where personnel and equipment decontamination take place. Decontamination is the removal of the hazardous material from items or personnel that have come in contact with it. Typically, this involves a simple soap and water rinse to prevent further spread of the contaminant outside the hot zone. The warm zone also includes control points for access to and egress from the hot zone and assists in reducing the spread of contamination.

The "cold zone" begins where the warm zone ends and spreads away from the material. The cold zone typically contains the command post, the staging area for resources and other support functions used to control the incident. It also helps prevent the spread of the material involved.


For HAZMAT incidents, the telecommunicator may be asked to call the Chemical Transportation Emergency Center (CHEMTREC) at (800) 424-9300 for additional information on the substances identified by the placards. Outside the continental United States, call (202) 483-7616. CHEMTREC, established in 1971 by the chemical industry, is a public-service hotline, available 24/7 for emergency responders to obtain information about and assistance with incidents involving hazardous materials.

In addition to providing advice, CHEMTREC will contact the shipper responsible for the material for more detailed information and on-scene assistance when feasible.

When calling CHEMTREC, the telecommunicator will need to provide the following information:

  • Agency name and callback number
  • The location and nature of the problem
  • The name or ID number of the materials involved
  • Any shipper or manufacturer information available
  • The container type (including physical description)
  • Any rail car or vehicle numbers visible
  • The carrier's name, if known
  • The receiver to whom it is being shipped to, if known
  • Local conditions, including the weather, forecasts and the geography of the incident scene

The weather and geographic information will be needed to determine the appropriate response to the incident. Weather effects on the incident include gusting winds that could blow gas clouds into populated areas or rain that could wash the contaminate into water systems. Geographic conditions could include valleys in which dense gases can accumulate, causing a buildup of gas and increasing the potential for explosion, or a densely populated area where risk of injuries to the public is increased.

While HAZMAT events are complex and demand increased attention to detail by all involved, a systematic response both in the communicatioins center and in the field will ensure the safety of the responders and the community. Always follow your agency's policies and procedures for response to these types of calls and refer questions to your supervisor.

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