Tips from the Hazardous Material Professionals
HAZARDOUS MATERIALS
Most fire departments have a predetermined plan or a standard operating procedure (SOP) for responding to and handling various types of emergencies.
In some instances, employing SOPs may be all that’s required to confine and extinguish a fire. At more complex incidents, SOPs may be used to provide adequate fire defense while awaiting the arrival of additional or mutual aid units.
SOPs can also serve to reduce confusion and increase efficiency at “unusual” incidents, such as a hazardous material emergency.
Experienced first responders to hazardous material incidents also use a type of SOP, which involves similar basic strategies and practices.
- Experienced first responders tend not to rush in, but rather stop as soon as they see the incident and use binoculars, if necessary, to perform a cautious evaluation and size up. It is generally agreed that hazardous material incidents require a more cautious approach than do structural fire situations.
- Experienced first responders tend to view command post operations as the on-scene manifestation of extensive pre-planning. If operational plans have not been written, problem areas not recognized and addressed, resources and expertise not identified, and personality conflicts not resolved ahead of time, a command post will not solve your problems.
A command post is an operational control device designed to maintain previously made agreements and relationships. Successful command post operations presuppose a written plan. The purpose of a command post should be to provide the incident commander with a means of coordinating field operations in order to resolve a crisis situation in an orderly and expeditious manner. The most often asked ques-tion at a hazardous materials incident is “Who’s in charge here?” Having one central point where all information is processed, decisions made, and tasks assigned, provides a strong indication to the public, to emergency services agencies, and to the media that someone is, in fact, in overall charge of the scene. Without a command post, control, coordination, and communications will tend to be hit or miss.
A command post should be established as soon as possible to facilitate initial decision making and control of the incident. At a major incident, a temporary command post should be set up immediately, then relocated when a more appropriate facility is found. It is not unusual to have to relocate a command post. Shifting winds, new information, desire for better facilities, problems with communications, need for additional space, or an inability to provide security for the command post initially selected, could all be reasons for relocation.
SOPs can serve to reduce confusion and increase efficiency at hazardous material emergencies. Experienced responders use a type of SOP, which involves similar basic strategies and practices.
As the name implies, a command post is where the people having the authority to make decisions and the people necessary to support and direct these decisions are brought together. A command post is normally separate from, but close to, the staging area where responding personnel report with their equipment to await directions. Not everyone reports to the command post. If fire, police, civil defense, federal, state, industrial, commercial, military, medical, and other personnel arrive on the scene, they are directed to the staging area. The person in charge of a support agency will report to the command post to make his presence known, provide information, or stand by for instructions. A command post can easily be overrun with people peripheral to the overall effort if steps are not taken to control access. Only if all information is fed to the command post and all assignments originate there, can an orderly effort be maintained at a major incident.
- Experienced response personnel attempt to immediately and positively identify the hazardous material in order to learn its reactive characteristics and the proper containment and control methods. They try not to commit personnel until they know what they are dealing with, and may contain their activities to evacuation and exposure protection until positive identification of the product has been made.
- Experienced first responders never underestimate an incident. “Just a tire fire” can become a cruel joke if the cargo on a highway vehicle is unknown and forces are committed.
- In making an approach, experienced responders avoid visible concentrations of smoke, fumes, vapors, and liquid. They approach from upwind and upgrade using natural barriers for protection. Unmanned equipment such as monitor nozzles are used when and where possible. They recognize “no fight” situations such as fires involving explosives or flammable gases when no life and minimum property is endangered.
- Experienced responders use the buddy system during containment efforts, and never allow a man to operate alone. They erect a wind directional indicator when vapors, fire, smoke, or dust are present. Recognized and agreed-upon emergency signals (such as hands and arms held directly over the head) are used to indicate serious distress, as would be the case if an
- acid-gas entry suit is ripped or penetrated.
Radio or voice communications will be difficult. Simple hand signals or chalkboards are often used to provide critical information under conditions of extreme noise or limited visibility. Teamwork is essential, as one experienced responder notes: “When the adrenalin starts to flow, teamwork becomes super critical. Working under a tank car in an acid-gas suit with a toxic product cascading, you have to know that your partner will hand you the tool you need without being told.”
Response personnel also tend to have a recognized signal for retreat. They realize that they may find themselves in a situation where a chemical reaction is about to run its course, and no action can be taken that will have any effect on the outcome.
• Experienced responders recognize that with flammable liquids, it’s the vapor, not the liquid that burns. Vapor spreads unseen, and responders are careful to monitor its concentration and identify its perimeter. The first priority is not to extinguish flammable gas fires, but to stop the flow of vapor, lest it spread unseen throughout the area to find a source of reignition.
• Experienced responders have a working knowledge of basic chemistry. In working with closed containers, they are aware of both Boyle’s Law (volume is inversely proportional to pressure) and Charles’ Law (volume is directly proportional to temperature). Nearly all response teams carry inexpensive pH papers to determine if a substance is an acid or a base in order to know how to neutralize the material. The pH scale runs from 0 (strong acid) to 14 (strong base) with 7 being neutral.
Responders understand specific gravity and solubility of materials and how they will react in water; they know the vapor density of gases and vapor.* They also know where to obtain such information for specific chemicals (National Fire Protection Association, CHEMTREC, National Institute for Occupational Safety and Health, Environmental Protection Agency, CHRIS manual, etc.).
• Experienced first responders make every possible effort to contain spilled hazardous materials and limit contamination to the smallest possible area. Containment is necessary to insure health and safety, protect property, avoid unnecessary environmental damage, and minimize potential liability. Containment includes not only the immediate control of the spill, but continuous control of manpower and equipment as well.
* Specific gravity is a measurable quantity assigned to every liquid. Water arbitrarily is given the value of one. A liquid that will float on water has a value of less than one. A value of greater than one indicates that water will float on the liquid.
Vapor density is the weight per unit of volume of a pure gas or vapor. Air is assigned a value of one. A gas with a vapor density of less than one is lighter than air and will rise. Conversely, gas with a vapor density of more than one will pool in lower areas and displace the lighter air.
Appropriate use of water is a prime consideration when attempting to contain a hazardous materials spill. Washing a toxic chemical into a storm drain, sewer, water source, or wildlife habitat can create a secondary emergency far more serious than that posed by the original spill. Water may dilute the chemical, but it will spread it as well. Commonly used containment techniques include dikes, dams, sumps, booms, and diversionary waterways.
- Don’t rush in. Evaluate and size up the situation.
- Treat the command post as the onscene operational control device.
- Identify the product, its reactive characteristics, and proper containment and control methods.
- Don’t commit personnel until positive identification of the product is established.
- Never underestimate an incident.
- Avoid visible concentrations of smoke, fumes, vapors, and liquid.
- Approach from unwind and upgrade, using natural barriers for protection.
- Recognize “no fight” situations.
- Use the buddy system—never send a responder in alone.
- Use recognized and agreed-upon emergency signals to indicate distress.
- Set up careful, continuous monitoring of vapor perimeters and concentrations.
- Have a working knowledge of basic chemistry.
- Contain spilled hazardous materials and limit contamination.
For products that float and are insoluble in water, as are most petroleum products, an inverted siphon dam (sometimes called a pipe skimming dam) is commonly used to separate product from flowing water. A dam of earth or sandbags is constructed over and around pipes that pass through the lower portion of the dam. These pipes are inclined slightly so that the low end accepts the stream flow and the high end discharges it. The pipes are then blocked until the dam has pooled water/contaminant to above the intake level of the pipes. Insoluble contaminants with a specific gravity of less than one will rise to the surface of the pooled water. The pipes can then be unplugged and the uncontaminated water allowed to flow back through the pipes. The contaminated water remains behind and can be picked up with pumps, skimmers, or sorbent materials.
A material that is insoluble in water and has a specific gravity of greater than one will tend to sink in water. If total flow is limited, a dam submerged just slightly below the surface will contain the sunken contaminant while allowing excess surface water to flow over the dam. Dams are of no use with soluble contaminants unless it is feasible to dam the entire water flow.
A spilled hazardous material may also be a powder, granular material, or dust that could be spread by wind or carried away on clothing, footwear, or equipment used by response personnel at the scene. Salvage covers or tarps offer some protection from wind, and personnel and equipment can be controlled.
Site control, zonal delineation, and decontamination are used to prevent unnecessary distribution of contaminants by personnel and equipment. Site control insures that only personnel and equipment absolutely necessary to control the situation are allowed into a contaminated area. Limiting traffic of people, vehicles, and equipment into and out of a contaminated area is both a health and a safety measure and an effort to limit transfer of contamination.
Zonal delineation is a component of site control. A danger area (hot zone) immediately surrounding the spill area is clearly marked, an entry/exit checkpoint is initiated, and all personnel/equipment deemed necessary to enter/exit the central area pass through this checkpoint.
An outer circle around the hot zone contains the decontamination area. All entry/exit is through a control point, and the area is considered to be potentially contaminated. All decontamination is handled within this area, and no person or piece of equipment is allowed to exit until being checked for contamination and decontaminated if necessary. Decontamination can include washing and rinsing of personnel, personal protective equipment, and general equipment and materials. It also includes the proper disposal of clothing/equipment/apparatus that cannot be successfully decontaminated.
A third outer circle is considered the staging area, a non-contaminated area for support activities, operation of a command post, preparation of equipment and personnel needed within the decontamination or hot zones, and provision of briefings to officials or members of the media. Stringent zonal delineation requires extensive planning, personnel, and equipment, and normally applies to situations where the volume or toxicity of a hazardous material warrants extreme care.
