Preincident Planning for Pesticide Fires
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HAZARDOUS MATERIALS
The best response when pesticides burn may go against a firefighter’s instincts. Know ahead of time how to handle the fire.
The lieutenant on the first-arriving engine company quickly reported a working fire as the rig pulled into the parking lot of the My town Farmers’ Cooperative building. Heavy smoke was pushing from beneath the eaves of the single-story, 75-by-200-foot, wood frame and metal-clad structure.
As the engine company was laying supply lines, the fire flashed over, and the entire north end of the building erupted in flames. A second alarm was requested, to be followed by a third within five minutes. Master stream appliances were set up to halt the progression of the fire through the uninvolved half of the building. Handlines were deployed to attempt extinguishment.
Soon 2,100 gpm of water were being poured into the building, and the fire was contained. There remained pockets of flame within the structure, however, and it promised to be a long night. Much interior extinguishment and overhaul lay ahead for the firefighters.
Several of them began to realize they weren’t feeling well. Headaches, dizziness, and mild nausea were typical complaints. “What’s going on?” they wondered. “We’re all wearing full protective clothing and SCBA!”
About this time, after 45 members had been working this fire for nearly an hour, the facility manager arrived. Seeking out the commanding battalion chief, the manager almost casually mentioned that the portion of the structure that was burning was where the cooperative stored its pesticide supply!
Pesticides! The very thought can chill the blood of the most seasoned fire service veteran if that person has any understanding at all of today’s chemical technology. The threat is clear from the word itself. Pesticide is a generic term that includes any chemical designed, manufactured, or sold to consumers to kill unwanted living organisms. There are many types: Insecticides kill insects, fungicides kill molds and other fungi, rodenticides kill rats and other rodents, herbicides kill weeds and othei^ plants, acaricides kill mites and spiders, and so on. Killing is the purpose they all have in common.
The fact that pesticides were being exposed to fire, coupled with the onset of the firefighters’ illnesses, caused an immediate change in strategy. “Pull all per-., sonnel out and shut down all lines except those being used to protect xposures,” the chief ordered.’ “We’re going to let this fire burn itself out. That will destroy th pesticides, making the situation much safer for everyone.”
But was this fictitious fire chief correct? Can and should a fire involving pesticides be handled passively—that is, should it simply be allowed to burn? Even more basic is this question: Why didn’t the chief and the firefighters know beforehand that this building contained pesticides?
(Photos by John E. Bowen)
The first question the story should raise is this: “Why didn’t these firefighters know from the moment they heard the address from their dispatcher that pesticides were stored there?”
The need for preincident planning has been drummed into our heads for decades, and rightfully so. But sadly, the task is too often neglected.
Do you know every facility in your response area where pesticides are manufactured, stored, sold, or used? You’d better, because your very life could depend on that knowledge. Imagine the direction our fictitious events could have taken had that manager not returned to the scene! Frightening prospect, isn’t it?
But you need to know more than the locations of pesticides—your preincident plan must include listings of the specific chemicals involved, the firefighting compatibilities, and appropriate strategies.
For example, why were the firefighters becoming ill at the scene of this fictional incident? After all, they were wearing full protective gear—high-topped leather shoes, turnout coat, helmet, leather gloves, and self-contained breathing apparatus.
Stop right there. High-topped leather shoes, leather gloves, and SCBA? It’s not so surprising then that they were developing symptoms of pesticide poisoning. Leather absorbs these chemicals and can never be cleaned. And, when the leather gets wet, you’re actually wearing a source of pesticides, because they continually leach from the leather, onto and through your skin, and into your bloodstream and vital organs. Never wear leather when working with pesticides!
But you say you don’t wear leather protective equipment? You always wear rubber boots? Depending on the specific chemicals involved, you may not be much better off than if you were barefooted! The rubber facepieces of some SCBAs pose a similar problem.
Some pesticides, notably the organophosphates and some of the fumigants, penetrate through rubber very quickly, almost as if it weren’t there. And even if your rubber boots are compatible with the pesticides you encounter, don’t forget the leather cuffs on many turnout coats.
So what should you wear at a pesticide incident? To be as safe as today’s technology allows, wear fully encapsulated suits specifically designed for use with the chemicals your preincident planning shows you could encounter. Not every pesticidal chemical will render your standard protective clothing and SCBA as useless as I’ve indicated, of course. Some materials will destroy your protection almost instantly, others will allow you full protection for a limited time. But unless you have absolute, infallible knowledge to the contrary, assume that fully encapsulated suits are mandated.
How do you know if you’ve been exposed to a hazardous chemical? You don’t necessarily have to await symptom development. Several of the most common pesticides—the organophosphate compounds and some of the carbamates—-poison people by interfering with the activity of cholinesterase enzymes, primarily acetyl cholinesterase. The enzymes function in the transmission of nerve impulses, and the extent of exposure to these pesticides can be assessed by measuring activity of the cholinesterases in the body.
But this, too, must be planned for ahead of time. The level of enzyme activity in the human body varies among individuals. Thus, the extent of enzyme inhibition due to pesticide exposure cannot be accurately determined unless your basal enzyme activity level before exposure is known. In effect, your preincident planning must anticipate that you may have contact with these pesticides.
How about our chief’s belated decision to let the structure burn “because that will destroy the pesticides”? Is this true?
The best answer I can give you is “maybe.”
The decision to let a pesticide fire burn under controlled conditions should be made during the preincident planning visit to the site and after discussion with the manager and owner. Many fire departments even include the facility’s insurance carrier in these discussions, finding that insurance companies often endorse such a plan because it simplifies clean-up.
Many factors have to be considered, of course. Exposures or your legal liability to an uncooperative manager or owner may render letting it burn impossible. If you opt to extinguish the fire, every gallon of runoff water has to be contained, neutralized, and then properly disposed of. And the anticipated fire may not burn hot enough or long enough to destroy the chemical anyway.
May not burn hot enough or long enough? You never thought about this, perhaps? The problem is the “three Ts” of chemical destruction by combustion: temperature, time, and turbulence.
Temperature is obvious. The fire has to be hot enough to decompose the pesticide—ideally to decompose it completely to water and carbon dioxide. How hot is hot enough? Very likely in excess of 2,000° F, a temperature not commonly reached or maintained in typical structure fires.
And what happens if the temperature is too low to decompose the material completely? Let’s draw an analogy from PCBs (polychlorinated biphenyls) here. After all, PCBs are chemical “first cousins” to many pesticides. PCBs decompose when heated to approximately 660° F. But they decompose into a group of compounds known as benzofurans, which are many times more toxic than the original PCBs themselves! So there’s no certainty that the decomposition products will become less toxic than the pesticide you’re trying to destroy if the combustion temperature is too low.
If you decide on a let-it-burn strategy, plan to give the facility maximum ventilation that will increase the flow of oxygen to the fire, thus accelerating the combustion. Boy, is this advice ever contrary to a firefighter’s training and instinct!
Letting it burn may mean you have to add fuel and oxygen to the fire.
The time that the pesticide is exposed to the high temperature— chemists call this “residence time”—also governs the extent to which it will be decomposed. Many buildings constructed of today’s most common materials won’t burn long enough to ensure pesticide decomposition. A let-itburn policy may mean that you actually have to add fuel to the fire to maintain the necessary temperature long enough.
The third factor, and the one that’s going to pose the greatest problem for your let-it-burn strategy, is that of turbulence. It’s very difficult to heat a mass of any material to the point at which the center of the mass is at the same high temperature as the surface. It certainly isn’t going to happen in a typical structure fire. Commercial chemical incinerator operators solve this problem by blowing solid materials into the fire as finely divided dusts. You won’t have this option available. So it’s quite probable that letting it burn will result in surface destruction of the pesticide mass with considerable original material remaining beneath.
(Incidently, many commercial incinerator operators won’t accept mixtures of chemicals for treatment, because of the many uncertainties introduced when various chemicals are mixed together. Take this fact as a warning to be especially careful in any fire response because rarely are you going to be confronted with an incident involving just one pesticide.)
Let me make just one more point about letting it burn. You already know, of course, that the smoke can be lethal. You can determine the direction in which the wind will carry it, but you can’t know to what extent unburned particles may be carried in the thermal column. Nor, for that matter, can you be sure to what extent you may have unwittingly produced decomposition products even more toxic than the parent compounds.
After any fire, there’s usually some sort of ash or residue that must be cleaned up. Usually this material is taken to an approved landfill for burial. However, this is a highly technical operation, and the task does not rightfully belong to the fire department. You’ve mitigated the emergency; I strongly urge you not to let the responsibility for clean-up fall upon your shoulders. Firefighters don’t have the training or equipment needed to properly clean up after a chemical release. Neither should firefighters have to face the additional risk of exposure from a nonemergency operation. Private contractors are usually called upon to handle this phase of the operation.
The subject of pesticides and their proper handling fills volumes and, indeed, libraries. Obviously, the subject can’t be fully dealt with in a single article. However, do consider the points presented here as you visit pesticide facilities in your response area and plan your strategy. Careful thought in the comfort of your office, as opposed to instantaneous decisions on the fireground, can save you much expense and grief later.
