While searching for an effective methodology to use for reference in developing its plans to deal with hazmat and WMD (Weapons of Mass Destruction) threats, the Virginia Department of Emergency Management’s Technological Hazards Division found a program that was both reputable and backed by science. That program, Chemical Profiling of Known Chemicals, came from the U.S. Coast Guard Environmental Response Division in Yorktown, Virginia, and has been used now for almost ten years by operations-level responders and technicians in the Commonwealth with considerable success. The chemical profiling included in the program is a relatively simple process that looks at and identifies the physical behaviors and hazards of the materials listed in the profiling document.
Five key evaluation points are considered in the process: (1) The ability of a specific product to release energy; (2) the “physical state” (solid, liquid, gas, or liquid with a gas component) of a specific material; (3) its potential flammability hazards; (4) its potential health and/or toxicity hazards; and (5) its potential corrosivity hazards.
To start working toward the development of ways to counter or at least mitigate the chemical hazards of the product it is first necessary to identify the chemical itself. There are several identification clues that can be used, including the following:
- the product’s UN/NA (United Nations/North American) identification number – this four-digit number usually can be found on placards, shipping labels, subsidiary placards, shipping papers, and/or other product labels;
- the product’s CAS (Chemical Abstract Service) number – which includes up to nine digits, separated into three groups by hyphens; the first part of the CAS number, starting from the left, has up to six digits; the second part has two digits; the third part is a single check digit;
- the product’s STCC (Standard Transportation Commodity Code), a seven-digit numeric code representing 38 commodity groupings. Assignment of an STCC code is linked to a commodity description developed to conform to the exact descriptions included in freight transportation classifications of rail and motor carriers.
Names and “Marks” of Materials
When a responder knows the name of a product there usually is no need to conduct a time-consuming search for all of its identification numbers. It is important to remember, though, that the numbers are used to find the name. Knowing the hazard also is important in understanding the primary hazard posed by a particular material (but it should be emphasized that many materials may pose multiple hazards).
The National Fire Protection Association (NFPA) has developed a helpful “704” marking system that can be used to determine potential dangers. The NFPA704, which is used for fixed facilities, gives the first responder a quick overview of the product’s potential health (blue), fire (red), and reactivity (yellow) hazards posed by the product.
A fourth section of the marking system gives a special warning (white) of additional chemical hazards. The potential hazards also are assigned numbers ranging from zero (0) to four (4), with zero meaning the hazard is minimal and four used to designate the highest hazard.
The next step in developing a profile is to determine whether the material is what is called a high-energy releaser and, therefore, both designed and intended to explode. There are three types of high-energy releasers that are of particular concern:
Explosive – Does the material fall into any of the Hazard- designations, assigned by the U.S. Department of Transportation, 1.1, 1.2, 1.3, 1.4, 1.5, or 1.6? If so, the material is a high-energy releaser and must be handled with extreme care.
Reactive – Does the material react with other chemicals? Are any of those chemicals present? Is any of the materials air- or water-reactive? If so, it usually is designated 4.2 or 4.3. Another significant question: Does the product react with itself, or does it polymerize?
Radioactive – Do the materials meet the U.S. DOT 7 classification? These are the only materials that qualify as radioactive.
On the right side of the form used by first responders there is a column that is headed with the word “Profile.” The column provides an easy way for the responder to circle or check off the hazard that has been defined by the reference points mentioned previously. The responder now is in position to develop an initial report based on the hazard information already accumulated. Using the information in the first and second sections, the responder can report on the primary hazards and start looking in closer detail at the safety and personnel-protection issues also involved.
The next section helps in classifying the physical state of the materials. The most important factors to be considered here are the material’s ambient temperature, its boiling point, and its melting point. Using those temperatures, the material can be evaluated as a solid, liquid, liquid/gas, or a gas.
As a point of reference it is worth mentioning that a boiling point of 300 degrees F is recommended to be used as a safety break. Here it also should be remembered that the lower the boiling point the higher the vapor pressure – and the more likely it is, therefore, that the product will either volatilize or become a vapor. Once the referencing work has been done, the boiling and melting points have been determined, the physical states have been verified, and other “profiling” work has been completed, a more detailed and more accurate evaluation can be carried out.
Gas Hazards, pH Ratings, and Related Footnotes
When evaluating gas hazards, the following properties are looked at first: flash point; ignition temperature; lower and upper explosive limits (LELs and UELs, respectively); and vapor density. Consideration of these as a group will give the responder the information required to determine the flammability of the material.
Various related information still is required, including whether the material is a carcinogen (cancer-causing agent), for example. Also, its permissible exposure limit (PEL) as well as a short-term exposure limit (STEL); whether it should be considered “immediately dangerous to life and health” (IDLH); and what amount of the product is considered to be a lethal concentration (LC).
This information focuses on health effects and assists in decisions related to protection of the civilian population as well as first responders; it helps considerably, for example, in selection of the personal protective equipment (PPE) needed by each group.
The last piece key piece of information needed is the material’s pH rating – pH is a common chemical term with many roots; in English it stands for “potential of hydrogen.” The pH rating is based on a measurement of the corrosiveness of the vapor/gas.
When evaluating a liquid hazard, its solubility and specific gravity are the properties looked at first (to determine the behavior of the liquid component of the material).
When evaluating a solid hazard, sublimation and combustibility are the most important properties to be determined. Here, a footnote is needed: if a specific solid meets the criteria of sublimation (the term used when a product passes from a solid to a gas), then the gas also must be evaluated.
All of this information will assist in evaluating the primary hazards that responders look for during a hazmat/WMD incident. The determination if the product is flammable, toxic, and/or a corrosive hazard – as well as an energy hazard, as determined earlier – can assist responders and incident commanders in developing safe tactical decisions as part of a solid Incident Action Plan, or IAP.
A final footnote: The skill required to carry out the research discussed above is difficult to acquire. It also is a very perishable skill, so should be refreshed and updated as frequently as possible. Such refreshing and upgrading can be carried out through a number of simple exercises that can be done once a month, on duty nights, in the station or elsewhere.
Glen Rudner retired in 2022 as a manager of environmental operations for the Norfolk Southern (NS) Railway with environmental compliance and operations responsibilities in Tennessee, Alabama, Mississippi, and Louisiana. Previously, he was the hazardous materials compliance officer for NS’s Alabama Division (covering Alabama, Mississippi, Louisiana, and southwestern Tennessee). Prior to NS, he served as one of the general managers at the Security and Emergency Response Training Center in Pueblo, Colorado. He worked as a private consultant and retired as a hazardous materials response officer for the Virginia Department of Emergency Management. He has nearly 42 years of experience in public safety. He spent 12 years as a career firefighter/hazardous materials specialist for the City of Alexandria Fire Department, as well as a former volunteer firefighter, emergency medical technician, and officer. As a subcontractor, he served as a consultant and assisted in developing training programs for local, state, and federal agencies. He serves as secretary for the National Fire Protection Association Technical Committee on Hazardous Materials Response. He is a member of the International Association of Fire Chiefs Hazardous Materials Committee, a member of the American Society of Testing and Materials, and a former co-chairman of the Ethanol Emergency Response Coalition. He served as a member of the FEMA NAC RESPONSE Subcommittee.