Back To Basics – Part 2

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First responders should become familiar with the U.S. Department of Transportation (DOT) hazard classes for hazardous materials and the placards and labels used to identify those hazards. This information will assist them when they use the Emergency Response Guide (ERG).

The DOT identifies nine hazard classes. Each class has a particular color associated with its placard and label. Placards and labels are diamond shaped. The placard is the largest and is used on the exterior of transportation vehicles and certain large containers. Labels are much smaller and found on the individual packages and small containers of hazardous materials.

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Photo by Robert Burke
The U.S. Department of Transportation (DOT) requires placarding of hazardous materials. The placards on these portable canisters indicate that they contain chlorine.

Also located on each placard and label is the hazard class number. This number is located on the bottom corner of the diamond. A symbol is found in the top corner of the diamond, and on most of the placards and labels a hazard class name is located in the center.

DOT regulations also permit the use of wordless placards, which are used throughout the rest of the world. Wordless placards do not have the hazard class name in the center of the placard, so responders should become familiar with the colors of placards and labels and the hazard class associated with each color.

Many times, the nature of hazmat incidents prevent emergency personnel from getting close enough to read what is written on the placards. However, the color of the placard can be identified from a safe distance or through binoculars. By associating the color of the placard or label with the hazard class, a responder can identify the hazard even if nothing is written on the placard.

Hazardous materials transported by rail, highways and waterways may be found with placards or labels. Usually, air shipments present a limited hazard, are in small packages and will be labeled. Pipelines are also a type of transportation system for shipping hazardous materials. Pipelines aren't placarded or labeled, but locations are marked with aboveground signs that identify the product and the pipeline company and provide emergency contact information.

Orange placards indicate explosives, DOT Class 1. The DOT identifies six subclasses of explosives. While these subclasses are identified by certain explosive characteristics, it is important that response personnel do not relate any of the classes with a lesser hazard than another. Responders may not know if the circumstances are present for an explosive to behave in a certain way. Therefore, all explosive classes should be treated as the worst case, that being detonation, until explosives experts arrive on scene.

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Photo by Robert Burke
NFPA 704 placards at a compressed gas facility.

Red placards indicate flammables and may be found in Class 2 (compressed gases with a flammability hazard) and Class 3 (flammable liquids). Flammable gases include propane, hydrogen and butane. Flammable liquids include gasoline, acetone, alcohols and ketones.

When response personnel recognize that a flammable hazard exists, they should take every precaution to prevent ignition of the material. Ignition sources include open flames, smoking, welding and other hot operations, heat from friction, radiant heat, static electrical charges, electrical sources, mechanical sparks and spontaneous ignition. Fire apparatus can be a source of ignition and should be positioned properly.

Compressed gases are a hazard class because of the pressure in the containers, which presents a hazard in addition to the physical and chemical characteristics of the gases. A green placard also indicates a compressed gas that is considered by DOT to be non-flammable. This can be dangerously deceiving, because anhydrous ammonia is placarded as a non-flammable compressed gas when, in fact, it will burn under certain conditions, usually inside a building or in a confined space. This is because the DOT definition of a flammable gas does not fit the flammable range of anhydrous ammonia. Other non-flammable gases include carbon dioxide, nitrogen, and argon. There is also a white compressed gas placard for poisons. Poison gases include chlorine and phosgene.

Flammable solid materials are Class 4 and have three different placards based on general hazards. The first is flammable solids, with a red and white striped placard. An example is a highway flare. Next are materials that are spontaneously combustible, with a white over red placard. Even though the hazard class is flammable solid, spontaneously combustible liquids are also included because they don't fit anywhere else in the hazard class system. One spontaneously combustible material is phosphorus.

The third flammable solid placard is all blue and indicates a material that is "dangerous when wet." These water-reactive materials include sodium and potassium.

Class 5 materials are oxidizers and have yellow placards. Oxidizers include swimming pool chemicals and oxygen.

Class 6 materials are liquid and solid poisons with white placards. These include liquids that are very volatile, but not gases, and infectious substances. Military and terrorist nerve and mustard agents and biological materials would be included in this category. Poison gases are placed in Class 2.

Radioactive placards are Class 7 and are yellow over white. Three radioactive labels are placed on packages according to the amount of radiation emitted by the materials.

Class 8 materials are corrosive with a white over black placard. Corrosive materials are acids or bases and include sulfuric acid and potassium hydroxide.

Class 9 materials are miscellaneous hazardous materials with black and white stripes over white. Miscellaneous materials include sulfur and hazardous waste.

DOT regulations, including the hazard classes, placards and labels, and others, undergo periodic review and revision. Response personnel need to watch for changes in transportation regulations.

Fixed facilities may also use the DOT placarding and labeling system for storage and use of hazardous materials. The Occu-pational Safety & Health Administration (OSHA) requires that all placards and labels in place during transportation remain in place during storage and use. The markings can be removed legally only after a container has been purged of the hazardous materials and has been disposed of properly.

The National Fire Protection Association (NFPA) also has a marking system used for fixed facilities storing or using hazardous materials. Unlike the DOT and OSHA regulations, NFPA 704 is an optional standard and does not carry any legal weight unless adopted by a local jurisdiction. Placards of varying sizes are used in the NFPA system to identify the major hazards of chemicals in a facility. It does not identify specific chemicals, but rather generic hazard classes. The hazard classes by color are not all the same as the DOT hazard class colors.

Each NFPA 704 placard includes four colored sections indicating particular hazards: blue for health, red for flammability, yellow for reactive and white for miscellaneous information such as water reactivity, corrosiveness and radioactivity. Within the colored sections of the placard are placed numbers 0, 1, 2, 3 or 4 to indicate the level of severity of the hazard that the material in the hazard area presents. A 0 indicates no hazard and a 4 indicates the most severe hazard.

The military also has a placarding system for explosive materials, chemical agents and biological materials. That system uses orange placards of various shapes to indicate levels of fire and explosion hazards. If your jurisdiction is near a military facility or has mutual aid with one, you should be familiar with the military marking system.

Additional sources of information about hazardous materials include shipping papers and Material Safety Data Sheets (MSDS). Shipping papers can be found with four of the five DOT transportation systems.

Railroad shipping papers, called a "way bill" or "consist," are found in the engine.

Highway shipments have shipping papers called the "bill of lading" or "freight bill" and are located in the cab of the truck, usually in a slot in the driver-side door.

Water transportation vessels carry shipping papers called the "dangerous cargo manifest," located in the wheelhouse. If a barge is involved, the shipping papers are also found in a small container on the barge. A barge may also fly a red pennant indicating that it is carrying hazardous materials. Even though the pennant is red, the color doesn't identify a particular hazard class.

Aircraft transporting hazardous materials carry shipping papers called the "air bill," located in the cockpit with the pilot.

A simulation of shipping papers can be found inside the front cover of the ERG, with an example of the type of information the papers contain. Typical shipping papers provide an emergency contact number for the manufacturer of the hazardous material, number and type of packages, chemical name, hazard class, quantity of product and UN identification number. Quantities will be listed using the metric system of weight, so response personnel should have a working knowledge of the metric system. The shipping papers may also identify a quantity of material, which must be reported to the National Response Center (NRC) if released, and will be marked "RQ," indicating a reportable quantity. Materials marked RQ are on the U.S. Environmental Protection Agency (EPA) list of materials that must be reported if released into the environment. The emergency contact telephone number at the top of the first page of a shipping paper should be called for response information, rather than CHEMTREC. If the shipping papers are not available, then CHEMTREC should be called.

MSDS are found at fixed facilities storing or using hazardous materials. Facilities with extremely hazardous materials identified by the EPA and Local Emergency Planning Committee (LEPC) are required to submit MSDS to the local fire department. The LEPC is created as a result of the Emergency Planning and Community Right to Know Act of 1986 (EPCRA). This act allows the local fire department to access any facility in the community that stores or uses hazardous materials for the purpose of pre-planning a hazmat release. MSDS contain chemical names, synonyms, hazards, protective equipment, and spill cleanup and decontamination information.

Protective Measures

Protection for first responders includes procedures for both the emergency responder and the public who may be in harm's way of hazardous materials. Protection is accomplished by four general methods: identify, establish and deny entry to the hot zone, wear proper protective clothing, and evacuate or protect in place. The hot zone, or exclusionary zone as it is sometimes called, is where the hazardous material or anything that has contacted the hazardous material is located, including victims.

Protection of responders and the public starts with denying entry to the hot zone. Denying entry is simply keeping everyone, including responders, out of the hot zone by placing barrier tape, posting personnel or police, or using public address equipment.

Hazardous materials can cause injury or death to responders and the public in various ways. These hazards are thermal, mechanical, poisonous, corrosiveness, asphyxiation (chemical and simple), radiation and etiological (biological).

Simple asphyxiation means there isn't enough oxygen in the air to breathe. It has likely been displaced by another gas. Chemical asphyxiation involves a material that enters the body and prevents it from using oxygen. A chemical that acts in this manner is cyanide.

People exposed to hazardous materials or terrorist agents can suffer psychological harm from the experience, or believe they were exposed to the materials and even experience symptoms when, in fact, they did not contact the material. There were over 5,000 victims of the sarin terrorist incident in the Tokyo subway; only 1,000 were exposed, the others experienced physiological symptoms.

Victims must be decontaminated before EMS personnel provide treatment. First responders at the hazmat awareness level can perform emergency decontamination to remove hazardous materials. In some cases, however, victims may need to go through technical decontamination before treatment by EMS personnel. If first-responding emergency personnel do not follow proper awareness procedures, they may become victims themselves and have to remain in the hot zone to await decontamination.

Hazardous materials and terrorist agents can enter the human body by four primary routes: inhalation, ingestion, absorption and injection through an opening in the skin. Wearing proper protective clothing or maintaining a safe distance will help reduce the chance of these types of exposure.

Properly approaching an incident scene can also reduce the chance of exposure. Scenes should be approached from upwind, uphill and upstream whenever possible, but always upwind. Responders should make use of protective equipment available to them or withdraw from the area if they have no protection. Respiratory protection is the most important concern when dealing with potential hazardous materials or terrorist incidents.

Materials such as gases and volatile liquids that present respiratory dangers are the most serious of the hazardous materials that could be encountered. Not all airborne hazardous materials are visible or have a taste or an odor, so response personnel should wear respiratory protection even if no hazards appear to be present.

Firefighters generally have the highest level of respiratory protection available with their self-contained breathing apparatus (SCBA). This protection should be worn in conjunction with full firefighter turnouts when it is determined the potential for hazardous materials or terrorist agents is present. This procedure should be followed even if there are no indications of trouble.

Testing conducted at the Aberdeen Proving Ground in Maryland on firefighter protective clothing exposed to military chemical agents have shown that firefighter turnouts provide a significant level of protection should personnel wander unknowingly into a terrorist agent. It should be understood, however, that responders should not knowingly go into a hazardous material or terrorist agent with firefighter protective clothing.

Responders should avoid contact with any hazardous material or terrorist agent, no matter what its form. Usually, liquid and solid hazardous materials and terrorist agents are evident when spilled. Personnel should avoid contact with these materials even if wearing proper protective equipment.

EMS personnel, police officers and other responders may not have respiratory or other protection available. These personnel should stay a safe distance from the potential hazardous material or terrorist agent until personnel in proper protective clothing, using instrumentation, can identify the dangers.


Robert Burke, a Firehouse® contributing editor, is the fire marshal for the University of Maryland. He is a certified Hazardous Materials Specialist, and has served on state and county hazmat response teams. Burke is a veteran of over 18 years in the fire service, in career and volunteer fire departments, having attained the ranks of lieutenant and assistant chief, and served as deputy state fire marshal. He has an associate's degree in fire protection technology and a bachelor's degree in fire science, and is pursuing a master's degree in public administration. Burke is an adjunct instructor at the National Fire Academy. He is the author of the books Hazardous Materials Chemistry For Emergency Responders, published in 1997, and Counter-Terrorism For Emergency Responders, published in 1999. Burke can be reached on the Internet at robert.burke@worldnet.att.net.

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