Hazmat and Habitat
The primary concern of first responders to hazardous materials incidents is, justifiably, prevention of personal and property loss. However, increasing responsibility is being placed on hazardous incident response teams (HIRTs) to identify and control environmental hazards from accidental chemical releases. Although few firefighters have had training regarding these hazards, failure to identify and prevent them will diminish the HIRTs’ overall response effectiveness, and could even cause further, inadvertent damage.
Preventing the long-term consequences of a haz-mat release isn’t a typical function of public and industrial HIRTs. However, if a response team understands the environmental impact of the release, it may modify its tactics and, in doing so, prevent further damage to the environment.
Spills can have three major effects on local ecosystems (local habitats with all their living organisms): They may destroy part or all of the natural organisms; they may impair ecosystem functioning by altering habitat, organisms, or chemical interactions; and they may throw the local ecosystem out of balance, an effect that can last a long time if the spill involves persistent toxic compounds, such as polychlorinated biphenyls (PCBs).
But not all releases will hurt the environment. They fall into four categories:
- Spills of nonpersistent materials—substances that rapidly degrade in the environment for a variety of reasons—into areas from which rapid dispersal of the chemical is likely;
- Spills of nonpersistent materials into places where rapid dispersal is unlikely;
- Spills of highly persistent materials—which remain relatively unchanged—into systems in w’hich rapid dispersal is probable; and
- spills of persistent materials into systems where dispersal isn’t likely. Substances typically encountered during leaks or spills will fall into one or two of these categories, depending on the chemical and where the spill occurs.
Spills in the first category, of nonpersistent and rapidly degrading chemicals that disperse rapidly from the site, aren’t likely to cause major environmental damage. Examples include spills of compounds such as sodium hydroxide or hydrochloric acid into a stream or river that disperses the substance. Organisms, such as birds, fish, and mammals, will probably avoid the spill area. And although these chemicals can kill off bacteria that play major roles in biological processes, if adequate dilution occurs, these nonpersistent and rapidly degrading chemicals create the least environmentally damaging type of spill.
Spills of a nonpersistent substance that aren’t suitably dispersed or degraded will pose more of a hazard than the first category because the chemical will remain at adverse concentrations longer than if it had been dispersed. Marshes, ponds, and land ecosystems are especially susceptible.
Incidents involving persistent chemicals in which rapid dispersal from the scene is probable are, as a rule, the most dangerous to the environment. Substances in this group include chlorinated hydrocarbons such as PCBs and heavy metals such as mercury and cadmium. They can become lodged in soil or sediments and, in doing so, are more likely to undergo biomagnification, a process in which the concentration of the substance in food sources increases. The ultimate consumers of these food sources are often humans. Rapid chemical containment or spill control is, therefore, extremely important when dealing with substances in this category.
Fortunately for first responders, large, in-transit spills of these materials aren’t common; however, if encounterd, spills should usually be contained, not diluted, until the manufacturer of the product is consulted. Since the compound might not decompose for some time, large amounts of soil or stream sediment may eventually have to be removed to eliminate the substance from the area. This, of course, isn’t considered to be a HIRT function.
Situations involving persistent materials that don’t rapidly disperse also require rapid action to control and then contain the spill. Pits to control runoff are useful, especially if they’re clay-lined. Preventing dilution of the substance in water from hose lines or rainfall will reduce the clean-up time required of the manufacturer or shipper later. Because the majority of incidents involve only relatively small quantities of material, absorption is often the preferred method of disposal.
Factors to be considered when determining potential environmental impact include:
- What chemicals are involved;
- The characteristics of the substances, including:
- Solubility in water;
- Upper and lower flammability and explosive limits;
- Combustion products, if the substance is flammable;
- Boiling and melting points;
- Soil and water chemistry;
- Physical characteristics (color, odor, pH, and the like); and
- Chemical reactivity;
Photo by Gregg Noll
A poorly chosen response to a hazardous-materials incident can have effects that last for years.
Detection and Identification Equipment For Haz-Mat Incident Response Teams
Detector tubes for 30 of the top 50 common substances*
Additional tubes for localized needs, 10 tubes
Aqueous test kits for:
Organophosphonate Dissolved oxygen* pH*
Temperature and pH meter wand* Combustible-gas detector*
Combustibleand toxic-gas tracer Oxygen monitor*
Estimated Cost $ 300
1,050 (at $35 to $40 each) 400
650 (at $40 each)
Total cost: $3,670
Total cost of minimum items: $2,700
‘Should be possessed by all HIRTs for personnel safety and common hazard detection.
While not all of this information will be necessary in all incidents, using pertinent data will simplify the task of determining potential problems, the need for and extent of evacuation, and what additional resources are required to manage the situation.
There are a number of resources that are useful for determining the physical, chemical, and biological properties of hazardous materials, including the Chemical Manufacturers Association’s Chemical Transportation Emergency Center (Chemtrec), at 2501 M St. N.W., Washington, DC 20037. Others are the National Fire Protection Association’s Fire Protection Guide to Hazardous Materials; the Merck Index of Chemicals (Rahway, N.J.: Merck, Sharp, & Dohme); the U.S. Coast Guard’s Chemical Hazards Response Information System Manual; the Chemical Rubber Co.’s Handbook of Chemistry and Physics (Cleveland, Ohio: CRC Press); L. Bretherick’s Handbook of Reactive Chemical Hazards (Stoneham, Mass.: Butterworth); and N. Irving Sax’s Dangerous Properties of Industrial Materials (New York: Van Nostrand, Reinhold).
Computerized reference systems are also available, such as the U.S. Environmental Protection Agency’s Oil and Hazardous Materials Technical Assistance Data System (OHM-TADS and microOHM-TADS); microCHRIS, developed with the Coast Guard and available from Firstsystem in Great Neck, N.Y.; and Lab-Link, from Mallinckrodt Inc. of St. Louis. Such systems allow’ excellent data retrieval and even direct computer connection, which eliminates mistakes in verbal transmission. While many teams spend a lot of money on equipment, few have, or properly use, an on-scene computer for data acquisition, storage, preplanning, personnel management, and resource allocation. However, even an excellent computer system won’t replace a reference library, since computers have been known to “go down” when their power supply is interrupted.
Monitoring equipment is useful for ascertaining the extent of the spill, ensuring personnel safety, and determining potential impact. The equipment can range from pH paper to specific indicators (see table). Although detection equipment is expensive, it’s a worthwhile investment for active HIRTs because it allows tracking of substances after large spills, and this increases the level of protection available to on-scene firefighters. Spreading the cost over several HIRTs or departments may make the items affordable, especially in volunteer units with limited resources. [For descriptions of additional monitoring equipment, see “Organizing a Hazardous Materials Response Team,” by Warren Isman, in the May 1983 issue of Fire Engineering.]
If feasible, HIRTs should carry specific test kits for both gases and liquids that are likely to be encountered during incidents in the firstdue area; the former could be a multigas detector or an electronic device, and the latter could be a colormetric or titration kit. As an alternative, reliable plastic strips with reagent pads that are useful for several tests (ammonium, chlorine, and hardness, for example) have become available at reasonable prices (15 to 35 cents per test).
Chemical tests do have limitations, regardless of whether they’re used in the laboratory or the field, and firefighters must be adequately trained before using tests in emergency situations. To take one example, tests designed for gases may be useless if the gas has diffused well. It’s important to measure the substance at a safe distance from the incident site and then repeat the measurements at decreasing distances while observing safety precautions.
When a spill involves a waterway, pH, temperature, and dissolved oxygen (DO) concentration should be monitored frequently. These parameters can be easily checked by HIRT personnel and can provide useful information, especially regarding movement of the spill, to the scores of industrial and regulatory officials who respond to a major haz-mat spill.
Firefighters can use electrochemical devices (pH meters) or sensitive pH test papers. The values obtained will range from 0 to 14, with 7 being neutral; values less than 7 are acidic, while those greater than 7 are basic. As a rule, the pH should fall between 5.5 and 8.0 in soil and between 6.0 and 9.0 in water, but it may vary widely depending on the composition of the material being measured. However, monitoring of pH after aquatic—or terrestrial—spills is useful in all types of incidents and not just those involving acids and bases. The pH of the water may affect toxicants that ionize, or become electrically charged; these may be able to enter aquatic animals, including fish, more easily.
Monitoring temperature and dissolved oxygen in a waterway will also provide information to industrial and regulatory officials who may not arrive on scene for quite some time. Temperature is an important factor when evaluating the fate of the spilled chemical, while DO is important when determining the effects of the spill on natural organisms; both function as factors that act to modify the toxicity of the spill. Water hardness, a measure of calcium and magnesium molecules in water, is also important, because some chemicals are less toxic in hard water than in soft. If dead organisms are seen in the spill area, collecting a few will be useful for determining the movement and impact of the spill.
If possible, HIRTs should conduct basic chemical tests of major waterways and potential industrial spill areas in the first-due area as part of the preplanning and training process. This will heighten industry’s awareness of HIRT activities and provide baseline information to regulatory and industrial officials. The process will also reveal to HIRT members the amount of the expertise that will be available during an incident, as well as whether industrial personnel have collected environmental data about their site and its surroundings before there’s a spill.
Conversely, industrial specialists should enlist the resources of the HIRT team prior to any incidents so personal, property, and environmental losses can be kept to a minimum. Prompt evaluation of the type, amount, and direction of the spill will also assist in potential evacuation planning.
When a spill does occur, many initial tactical decisions are made without directly considering the environment; but follow-up actions must take the environmental ramifications into account. The officer in charge of haz-mat incidents must be aware that certain actions or inactions could actually worsen the situation. By understanding how specific approaches may, in themselves, increase the hazard to the environment, the officer can choose alternative methods after consulting with regulatory and industrial officials.
Initial control of the spill, in a way that ensures personnel safety, is of paramount importance. The less product that’s spilled, the less damage that will be incurred. Applying a rubber stopper, neoprene ladder, or hardening foam agent or placing spill-containing materials around the haz mat during initial operations may at least slow major leaks and reduce further damage.
Under no circumstances should first responders flush materials into sewers or waterways. That action has affected aquatic life, produced explosions, and altered biological treatment processes at municipal facilities. Fire departments have been fined for purposely flushing haz mats into sewers or storm drains. Any accidental spillage should immediately be reported to the local wastewater treatment facility so countermeasures can be taken.
Colormetric procedure—A chemical test that determines the amount of a substance based on a color reaction.
Ecosystem—A living community plus its habitat. An example is a field and the organisms that live in it.
Lethal concentration 50 (LC50)—The amount of a substance that will kill 50 percent of the animals in a test during a given period, usually 96 hours.
Nonpersistent substance— One that rapidly degrades in the environment because of biological, chemical, or physical factors.
Persistent substance—One that remains in the environment despite dilution and other basic steps intended to remove it; examples include PCBs and methyl mercury.
Dilution has commonly been used to resolve hazardous substance spills. If dilution is deemed suitable, the runoff must be adequately contained, preferably by diking into plastic containers or plastic-lined pits. But unless the situation is life-threatening, dilution shouldn’t be used at major chemical spills, because large amounts of water—up to 100 times the spilled volume for some liquids—may be required to dilute the substance adequately; this volume may prove impossible to control. Few teams have the resources to calculate the amount of diluent to add without an on-site regulatory or industrial official, and containment and absorption of the substance will probably provide better environmental protection.
Neutralization of the spill, which is useful for acids and bases as well as other substances, also requires the administration of calculated amounts of the appropriate agent. Crushed lime, sodium carbonate, and sodium bicarbonate have been used for acid spills, while hydrochloric and sulfuric acids have been used to neutralize alkaline spills. Overuse of these agents may, in itself, produce a hazard, so they should be used only if other methods, such as absorption, aren’t suitable and only after consulting with the industrial and regulatory officials.
Putting these principles to work for the sake of the environment takes extensive training in haz-mat chemistry and risk assessment, as well as practical experience. Because ecosystems are as diverse as the chemicals that are placed into them, there will be exceptions to which the generalities described here don’t apply. Individuals responsible for emergency response should consult with a local ecotoxicologist regarding unique characteristics of their response area.
Finally, the potential of an incident should never be underestimated, and team members should be constantly aware that human safety is the most important aspect of a haz-mat incident, even at the expense of the environment.