The Building Blocks of Hazmat:

Don’t Throw Away the Basics

CarolinaFireJournal - Glenn Clapp
Glenn Clapp CHMM, CFPS
01/14/2018 -

Although math was never my favorite subject in school, when I progressed to algebra — and we will not state how many years ago that was — a wise teacher said that actually using variables and solving equations was not what usually created the most challenges for students, rather that it was normally the use of basic math that became problematic. When I finally reached the realm of calculus — and what a struggle that sometimes was — another wise teacher stated that it was not the use of calculus that most often frustrated students but rather the use of algebra and basic math. Sounds like a pattern here, doesn’t it? 


The world of hazmat is very similar in that when we become hazmat technicians we tend to forget about the very building blocks of hazmat, those blocks being the concepts learned in operations level training. Those operations level topics are often the most likely to create problems on the hazmat response playing field. That very concept is underscored in teaching hazmat technician class when we tell the students that certain topics are operations level concepts and they should have covered them in their operations certification class, then we wait for the inevitable groans and complaints. As hazmat technicians, we should not toss the basics aside when we become technicians — or at any time in our hazmat careers for that matter — and should strive to maintain competency in those operations level areas that can be easily forgotten.          

Product Recognition and

One of the primary hazmat building blocks learned as an operations level competency is that of product recognition and identification. While hazmat technicians may employ detailed research techniques to identify products, the basic task of determining what we are dealing with at a hazmat incident is definitely within the operations realm. During the hazmat operations class for example, students are introduced to the nine DOT hazard classes that are utilized to group hazardous materials into classes of similar characteristics for shipping purposes. The nine classes can be easily remembered through the memory aid “Every Good Fire Fighter Ought to Practice Reading Current Manuals” in which the first letter of each word corresponds to the first letter of each of the DOT hazard classes:

  • Explosives
  • Gases
  • Flammable Liquids
  • Flammable Solids
  • Oxidizers
  • Poisons (Toxics)
  • Radioactives
  • Corrosives
  • Miscellaneous

The responder only has to remember that the classes are arranged from greatest hazard to lesser hazard. The DOT hazard classes will not only appear in the field, but questions relating to same will be seen in competency testing at every level of hazmat certification.

Another portion of the recognition and identification building block is that of the difference between package labels and markings. While labels on individual packages refer to smaller versions of the placards found externally on modes of conveyance, markings refer to the text identification and hazard information data found on individual packages. In addition, operations level personnel should be able to determine the type and specification of highway and rail transportation trailers and tank cars through visual observation. The keystone of product recognition and identification, however, is that of the use of the Emergency Response Guidebook (ERG). A copy of the ERG should be carried on every emergency response apparatus and allows us to identify products by their UN/NA four-digit number, product name, placard, or trailer/tank car silhouette; and to determine appropriate guidance for use in an incident. ERG training should be conducted at each annual hazardous materials refresher class for all hazmat certification levels.

Properties of Hazardous Materials

A second building block of hazmat is that of the chemical and physical properties of hazardous materials. Hazmat responders need to understand concepts such as flammable range, will the product go whoosh or boom; vapor density, will a gas or vapor rise or sink; specific gravity, will a liquid float or sink on water; and corrosivity, is the product acidic or basic. Although we often speak of such properties in detail in the hazmat realm at the technician level, a basic level of understanding of the concepts is required at the operations level. For instance, we need to know the specific gravity of a liquid product in the context of damming a waterway to curtail the flow of the product. A product with a specific gravity of less than one — less dense than water — will float and necessitate an inverted siphon (underflow) dam to trap the product, while a product with a specific gravity of greater than one — sinks in the water column — will require the construction of an overflow dam.

The theory and practical application of product control in the form of damming, as described above, to stop the migration of liquid product in a stream, creek, or other body of moving water; and the construction of a dike to prevent the extension of a product into a drain are two components of an essential building block of hazmat. While we think that product control lies within the technician realm of hazmat, product control in the context of staying out of the product itself or its harmful qualities while stopping the migration of the product is well within the purview of operations level response. In damming or diking, such actions are performed ahead of the spreading product and therefore are not hazardous to the responder if performed properly.


There are also operations level building blocks of hazmat that were viewed more in the context of technician level response in the past, but are now considered operations level tasks.  One of those areas is decontamination.  As we all know, even the most highly staffed technician level hazmat teams can be severely impacted by the personnel needs of decontamination.  If operations level personnel are properly trained in decontamination techniques, the appropriate use of hazmat personal protective equipment, and are supervised by technician level personnel they can serve as force multipliers to free up technician level team members for other needed duties.

Air Monitoring

A second area formerly viewed as that of a technician level capability but now lying within the operations realm is that of basic air monitoring. Fire service personnel are now performing air monitoring at natural gas leaks and carbon monoxide responses; as well as monitoring the atmosphere following structure fires to determine when responders can safely doff respiratory protection. Such activities are underscored by the fact that operations level personnel can also complete a mission-specific competency in air monitoring. As such, operations level personnel should be knowledgeable in the areas of air monitoring techniques, the type of and operational characteristics of meter sensors; the bump testing and calibration of monitoring equipment; and the concept of relative response when utilizing combustible gas indicator (flammability or lower explosive limit) sensors. If the sensor is being used to monitor for a gas or vapor other than that it is calibrated to, a relative response correction factor supplied by the manufacturer is required to be multiplied by the meter units indicated to obtain the percentage of the lower explosive limit encountered.

As can be seen in our discussion above, hazmat technicians often push aside the fundamental building blocks learned in operations class for technician level competencies. Although such technician level competencies are undeniably important, we should not neglect those building blocks upon which our hazmat foundation is built. Those items are likely to cause major challenges on hazmat response scenes if forgotten. As those wise math teachers who were alluded to at the beginning of our conversation above stated years ago, we should never throw the basics away.

As always, stay safe out there and be sure to visit the North Carolina Association of Hazardous Materials Responders website at

Glenn Clapp is a past president of the North Carolina Association of Hazardous Materials Responders and is a division chief with the Town of Fuquay-Varina, North Carolina Fire Department. He has over 20 years of fire service and emergency management experience and is a Technician-Level Hazmat Instructor, a Certified Hazardous Materials Manager, and a Certified Fire Protection Specialist.
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Issue 32.3 | Winter 2018

Keeping First Responders Safe
Ideas to improve safety on the job, leadership, serving our community and keeping the desire to serve others...