Hazmat Detectives — Food for Thought

Detective work does not normally come to mind when looking at the field of hazardous materials response. Depending on the authority having jurisdiction, training and/or certification to the technician level can be as short as 24 hours (OSHA technician) to more than 160 hours for certification through the North Carolina Fire and Rescue Commission. All training programs follow the basic requirements outlined in OSHA 1910.120 with regards to knowledge, skills and abilities required to be trained to the technician level. Training is not always able to provide clear answers for problems that a trained person has no previous experience. As an example, a hazmat responder who has limited experience with highway emergencies may struggle with managing an incident for which they are well trained. In a training evolution you may create the conditions for an active leak, but rarely are we able to train with a full size tanker truck overturned, damaged and actively leaking. Hazmat events where the products are known or the leak is obvious, present their own direct challenges. Hazmat events where the exact nature is not known require a different approach, one that may mirror that of a detective.


Considered the unknown odor call. A citizen(s) calls 911 and reports a strange odor. Typically a “first due” unit responds and investigates. The investigation may reveal no other clues. Such an event may or may not escalate to a hazmat response. Other factors have to be considered. Is anyone being affected by the odor? Is the odor recognizable? Is a source identifiable? Is there a history of similar events at the location or general area? One approach to consider would be to use the five Ws; Who, What, When, Where and Why. These five simple questions begin the first thread of what may become a complex story. Often two or more of these questions will connect key clues in a hazmat materials incident.


The question of “Who” is very subjective and there could be more than one “Who” to consider. “Who” could be the caller who may or may not be at the location? “Who” could be the party responsible for the spill or the last person to have worked on a system that is leaking? Another important “Who” to be answered revolves around authority. “Who” is in charge? The question of who is in charge is not in relation to the incident commander, but whom at an incident has responsibility for the location, facility or vehicle. Who’s who is an old expression that comes to mind to illustrate that any hazmat investigation requires a knowledge of the players that have to interact.


“What” is usually conveyed in the context of “What happened?” First responders should consider asking any callers, witnesses or bystanders to be very specific on this question. The answer could be very short and simple, such as they were at work when a strange odor was detected. The answer could be very detailed such as two chemicals were incidentally mixed resulting in a vapor cloud. In the context of “What,” no detail can be too trivial.


While the question of “When” might seem straight forward, the answers to this question might be surprising. It is not uncommon to have a caller report that something occurred an hour, a day, a week or a month ago. In some instances a caller might well report that this has been a chronic issue for months or years, but they have not received an answer or a resolution that is satisfactory. This question and the associated answer of when was a key detail on a fuel spill in a creek near a residence. The caller reported that they had seen the fuel in the creek approximately a month earlier, but decided not to notify anyone. A month later the caller smelled fuel in the creek next to their residence and elected to call 911 to report it. At this point in time there was only a residual amount of fuel in the immediate area and a small sheen that could be traced upstream only around 100 yards. Due to the extended time frame, investigation efforts were focused on areas several hundred yards upstream with the assumption that the spill had slowly migrated downstream. At the time of the investigation a confirmed source was never located. This changed a few weeks later following a significant rainfall. The caller resident made notification that the problem had returned. Responders and health department officials were able to see a point where fuel was being discharged into the creek. The source of the leak was an underground tank on an adjoining abandoned property. Nothing about the abandoned property indicated the presence of an underground tank. The area where the tank was located was overgrown with brush making any determination of an underground tank difficult. The fuel would only seep from the adjoining property during rainfall.

The caller had been advised after the previous response to immediately call if they noticed anything similar in the future. In this instance, the indication of a long time frame led the responders to check a larger area than was necessary. In retrospect, the actions taken were appropriate based on the available data, but that incident certainly added to the knowledge base for future responses.


“Where” an incident occurred is vital when the location of a hazmat incident is a fixed facility. Fixed facilities, especially chemical manufacturers, will have locations within their facility where raw materials are stored, injected into their process and a finished product emerges. There may also be an area where waste products from the process are directed. In a fixed facility scenario, it is crucial to understand what hazards or potential hazards may emerge in each of the areas of a process. When the incident is not tied to a specific incident location, but is transient in nature, a caller’s statements may be too vague to determine a clear source. I recall an intersection along a busy multi-lane road that often was reported as having an odor of natural gas. The 911 callers would report an odor in the area but never remained on scene. First responders would ride along the same route unable to detect any odor. A natural gas pipeline also passed near this intersection and an above ground pressure relief station for the pipeline was at the same intersection. Obviously these calls were often attributed to the close proximity of the pipeline and relief valve. However, one day a traffic accident forced the closing of the road in the southbound direction near the intersection. While on scene fire personnel were able to detect an odor of gas. Ultimately, with the involvement of the local gas utility, a small underground leak was discovered. This may have been the source of months of random odor calls, but until traffic was stopped no one could have known of an underground leak.


“Why” may be challenging to answer, especially with a hazmat incident that begins as an investigation of an odor or unknown solid or liquid. In some situations the “why” will not be known until all the other questions are answered or may never be known. “Why” could be the result of a mechanical failure, operator error or undetermined. The importance of “why” may not be immediately obvious and the concern with “why” should not prevent any first responder from taking action commensurate with safety of personnel. For example, a storage tank containing a chemical which may polymerize is determined to be increasing in heat and pressure. The reason “why” could be one of several possibilities, but the focus should be on the dangers such a condition pose and taking appropriate life safety actions.

Each of these questions and their importance can be illustrated by an incident I assisted with a few years ago. A rural fire district was dispatched to a hotel on a Sunday afternoon. The callers reported a vapor cloud in the pool area. The presence of a visible vapor cloud was confirmed on arrival by the first due company who requested additional units and the county’s hazmat team. At first glance, much of the initial details might lead one to wonder if some type of chemical reaction had occurred in the pool area. Indeed, the presence of a vapor cloud would suggest some type of chemical reaction. Given that chlorine is a key chemical added to water for sanitary reasons, the possibility of a chlorine release was present. Employees (the Who) reported that a smoke detector had activated (the When) and when they reached the pool area (the Where) a vapor cloud was visible (the What) at which point they evacuated the hotel. The missing element at this point is the “Why.” I was unable to respond to the scene, but in consulting with personnel en route and on scene, I recommended more information and details be obtained. The best avenue for that was to increase the “Who.” The building engineer was contacted who advised the chlorination system had been changed a few days prior and would not have been of sufficient content — using solid chlorination sticks — to charge a pool area with chlorine. This key detail matched with the one missing report by witnesses; no one had reported the odor of chlorine. HazMat and fire responders on scene were still left with no clear answer to the “Why.” The key detail was found when the manager was contacted by telephone. Having occurred on a Sunday, the weekday manager was not on site. The weekday manager (the Who) recalled that three days prior a contractor had repaired and recharged the dehumidifying system for the pool area. This detail fit with all other reports and provided a plausible cause for a vapor cloud without the odor of chlorine. This was the missing “Why.”

Air monitoring was performed with standard four gas meters and PIDs as well as colorimetric tubes specific for chlorine to rule out any possible presence of chlorine. The readings confirmed the absence of chlorine and a decrease in oxygen due to displacement from the Freon lost from the dehumidifying system. The area was ventilated and rechecked with air monitoring equipment and turned back over to the property representative.

Whether the event is an active hazmat leak with clear markings and labels or an unknown problem, a series of interrogatory questions are necessary to bring a solution into focus.

Alan B. Cagle is a Battalion Chief with the Greensboro Fire Department assigned Battalion 4. He is also a Team Leader and on-call member of the Guilford County Hazardous Materials Response Team. He started his career in the fire service in March of 1986 and has served on the County’s HazMat Team since July of 1988. He holds a B. S. degree from Guilford College and a Masters of Public Affairs from UNC Greensboro. He is an EMT – I with Guilford County EMS and a North Carolina certified fire service instructor. He can be reached via email at abcagle@gmail.com.

Contact Us

"*" indicates required fields

This field is for validation purposes and should be left unchanged.