Estimating Potential Harm and Planning a Response Notes

Estimating Potential Harm and Planning a Response

  • Incident response objectives should prioritize protecting and reducing threats to life, property, critical systems, and the environment.
  • After addressing the threat to life, focus shifts to minimizing impact on property and the environment.

Protecting Property and Minimizing Environmental Complications

  • American Conference of Governmental Industrial Hygienists (ACGIH)
    • Publishes toxicological data and sets guidelines (not laws).
    • A source of guidelines and information for over 80 years.
    • Threshold Limit Values for Chemical Substances (TLV-CS) Committee.
  • OSHA
    • Publishes toxicological data and sets standards that are law.
    • Created in 1971 and sets the permissible exposure limit (PEL).

Determining Contamination Levels

  • Common toxicological values related to airborne contaminations:
    • Parts per million (ppm)
    • Parts per billion (ppb)
    • Parts per trillion (ppt)
  • Substances other than gases:
    • Milligrams per cubic meter (mg/m3)(mg/m^3)
  • The lower the toxicological value, the more toxic the product.
  • Threshold limit value/short-term exposure limit (TLV/STEL):
    • Maximum concentration of hazardous material exposure.
    • Requires a minimum 1-hour rest period.
    • The lower the concentration, the more toxic the product.
  • Threshold limit value/time-weighted average (TLV/TWA):
    • Maximum airborne concentration of material exposure.
    • The lower the TLV/TWA, the more toxic the product.
  • Threshold limit value/ceiling (TLV/C):
    • Concentration of a hazardous material that should not be exceeded.
    • The lower the TLV/C, the more toxic the product.
  • Threshold limit value/skin (TLV/skin):
    • Exposure from absorption through the skin, mucous membranes, or eyes should be minimized.
  • Recommended exposure level (REL):
    • A comparable value established by the National Institute for Occupational Safety and Health (NIOSH).
  • PEL, REL, and TLV/TWA:
    • Represent the maximum, time-weighted concentration of material exposure.
  • Immediately dangerous to life and health (IDLH):
    • Atmospheric concentration of a toxic, corrosive, or asphyxiant substance.
    • Three types of IDLH atmospheres:
      • Toxic
      • Flammable
      • Oxygen deficient
    • Risks associated with exposure.
    • Assessing airborne contamination requires specific detection and monitoring instruments, along with training to interpret the results.

Applying Exposure Values

  • Three basic atmospheres or environments:
    • Green
    • Yellow
    • Red
  • These colors are visual representations of risk.
  • Consider the risk of taking no action, the types and levels of protection available, and how to ensure safety and health.

Plan an Initial Response

  • Planning a response involves understanding the nature of the incident, determining a plan of action, being mindful of safety, and identifying the responder role.

Initial Call for Help

  • Factors to consider:
    • Best route to the scene (upwind and uphill from the site).
    • Material involved and its state of matter.
    • Container type, level of activity, and characteristics of the affected area (population, traffic).

Resources for Determining the Size of the Incident

  • Understand the incident as a whole, considering methods used to obtain results and situational factors.

Response Objectives

  • Criteria for response objectives:
    • Measurable, flexible, time-sensitive, based on strategy, and carried out with achievable tactics.
  • Examples:
    • Build dirt berm.
    • Shut down the ventilation system.
  • Several incident objectives may be developed, with initial actions followed by reevaluation.
  • Continuously evaluate the effectiveness of strategies.

Offensive, Defensive, and Nonintervention Interventions

  • Offensive interventions involve taking action to mitigate the issue in the area closest to the release.
  • Defensive interventions involve actions taken in areas free of contamination.
  • Nonintervention is chosen when the hazard is too great, allowing the incident to self-stabilize.

Protective Actions at the Operations Level

  • Evaluate the threat to life, considering the severity of the incident, property or environmental impact, and life-safety actions.
  • Ensure responder safety first, perform search and rescue, and make decisions about evacuation as needed.

Evacuation

  • Evacuation: Removal or relocation of individuals who may be affected by an approaching release of hazardous material.
  • Consult reference sources, perform practice exercises, and imagine various locations or conditions.
  • Utilize the Emergency Response Guide (ERG) and United Nations (UN) identification number to identify emergency actions and PPE, and determine initial isolation distances or other protective actions.
  • Risk-based method involves weighing the severity of the threat.
  • Firefighters and law enforcement personnel should inform residents of evacuation.
  • Considerations for a safe area include large venues and temporary evacuation areas.
  • Initial evacuation distances should consider safety and practicality.
  • Use detection and monitoring devices.
  • Evacuation process involves preplanning, considering the time of day, season, security at shelters, law enforcement, access, media shield, transportation to temporary evacuation areas, special needs populations, pets, and evacuee motivation.
  • Challenging circumstances may include severe weather conditions, requiring provisions for protection and emphasizing safety.

Shelter-in-Place

  • Shelter-in-place involves remaining in an enclosed atmosphere.
  • Suitable locations include schools, churches, hospitals, nursing homes, and apartment complexes.
  • Intervention requirements include remaining indoors, closing windows and doors, and turning off ventilation systems.
  • Evacuation factors to consider include the toxicity of the hazardous material, amount of time available, expected duration of the incident, and the area of safe refuge.

Isolate and Deny Entry

  • Involves setting a perimeter to establish safe work zones at a safe distance from the release.
  • Isolation is accomplished by law enforcement and other public safety personnel, using barrier tape and human presence.
  • Isolation combined with denial of entry is essential for protecting personnel.

Search and Rescue

  • In a hazardous materials incident, identify the released substances.
  • The Incident Commander (IC) performs a risk-based assessment to determine if search and rescue is warranted.
  • Remove victims to the warm zone for decontamination and provide definitive medical care.

Consider Exposures

  • Physical areas adjacent to the fire include property, structures, and the environment.
  • The number of exposures depends on the location of the incident, properties of the substance, the amount of progress, and whether it is an urban area.
  • Determine when more resources are required.

Reporting the Size and Scope of the Incident

  • Information available at the scene includes the maximum capacity of the container and shipping papers.
  • Thermal imagers (TIs) can be used,considering factors like steel drums and wet soil for rough estimates.
  • Units of measurement must be used to express the size of the release, with accurate and clear communication being paramount for the safety of responders.

Personal Protective Equipment

  • Choice of PPE depends on
    • Material involved.
    • Hazards present.
    • State of material.
    • Tasks to be performed.
  • Chemical-protective clothing is required for harmful exposures, including corrosives, solvents, and poisons.
  • Respiratory protection is a high priority and should be determined after hazard identification.

PPE Limits

  • PPE has limits and the types and levels of PPE are detailed in HAZWOPER, NFPA 1990, and emergency response plans for the AHJ.
  • Cleaning, disinfecting, and inspecting PPE should follow manufacturer procedures.
  • Incorrect alterations should be avoided.

Excessive-Heat and Cold-Temperature Disorders Related to PPE

  • Heat Exhaustion

    • Signs and symptoms:
      • Increased core body temperature
      • Dizziness
      • Blurred vision
      • Acute fatigue
      • Headache
      • Muscle cramps
    • Treatment includes immediate removal from the heated environment, rehydration with electrolyte solutions, and cooling efforts; may progress to heat stroke

  • Heat Stroke

    • Signs and symptoms:
      • Reduction or cessation of sweating
      • Increased body temperature
      • Rapid pulse
      • Hot red skin
      • Headache
      • Confusion
      • Unconsciousness
      • Seizures
    • Requires immediate transport to a medical facility

  • Cold-temperature exposures:

    • Operating environment
    • Released materials

  • Body surfaces can sustain severe injury.

  • Environmental influences include temperature and wind speed.

  • Wet clothing contributes to perspiration and hypothermia.

Respiratory Protection

  • Protective ensembles and garments specific to WMD must meet garment performance standards outlined in NFPA 1990.
    Ensemble is only as good as individual components.
  • CBRN performance requirements for SCBA and APRs include performance against sarin and sulfur mustard, developed in response to terrorism.
  • Meet requirements of NFPA 1981 and NFPA 1986, with integrated performance guidelines.

Positive-Pressure Self-Contained Breathing Apparatus (SCBA)

  • Prevents exposure through inhalation and ingestion and is mandatory for fire service personnel.
  • Negatives:
    • Must carry own air supply.
    • Weight and reduced visibility.
  • AHJ training is needed, following manufacturers’ recommendations.

Supplied-Air Respirators (SARs)

  • External air source via hose connection.
  • Positive-pressure air-line respirator is useful during extended operations.
  • May include an escape cylinder of compressed air with 5 minutes of breathing air.
  • SARs weigh less than SCBA, but the air hose may limit movement and can sustain physical damage.

Closed-Circuit SCBA (Rebreathers)

  • Developed in mid-1800s, allowing for long work periods.
  • Exhaled air is scrubbed free of carbon dioxide, supplemented with a small amount of oxygen, and rebreathed by the wearer.
  • No exhaled air is released to the outside environment.

Air-Purifying Respirators (APRs)

  • Filtering devices or particulate respirators require that the type and quantity of contaminants are known and sufficient oxygen for breathing is available.

  • Operation involves volatile solids and remedial clean-up and recovery operations.

  • Forms include:

    • Full-face piece
    • Dual-cartridge masks
    • Half-mask
    • Face piece–mounted cartridges

  • No separate source of air; material soaks up or reacts with gas.

  • Cartridge selection is based on the expected contaminants.

  • Particle-removing respirators use a mechanical filter.

  • Atmosphere must contain a minimum of 19.5% oxygen.

  • Pros:

    • Easy to wear
    • Contaminant-specific cartridges

  • Cons:

    • Air must be continually monitored.

  • Before using, test ambient atmosphere and determine device safety.

Powered Air-Purifying Respirators (PAPRs)

  • APR with a small, battery-powered fan that draws in outside air via a low-pressure hose.
  • Advantages:
    • Diminished work of breathing
    • Reduced fogging in the mask
    • Constant flow of cool air across the face

Physical Capability Requirements

  • Health and safety management program addresses hazardous materials/WMD incidents and stress on responders.

  • Overview of a health and safety management system, as outlined by HAZWOPER, includes medical surveillance, medical monitoring, thorough recordkeeping, and review of the entire process.

  • Medical surveillance is key to effective health and safety management, with primary goals to determine if an individual can perform their assigned duties and detect changes in body system functions.

  • Medical monitoring and support differ from medical surveillance, identifying problems, preventing severe adverse effects, and maintaining optimal health and safety.

Decontamination

  • A procedure or plan for decontamination must be established.
  • The overall goal is to make personnel, equipment, and supplies safe by reducing or, in some cases, eliminating, the offending substances.
  • Contamination of PPE requires a process-driven activity determined by the nature of the contaminant.

Overview of Decontamination Types

  • Emergency/field decontamination
    • Immediately reducing contamination of people in potentially life-threatening situations.
    • Goals:
      • Reduce the effect of exposure.
      • Get victims clean enough to receive medical care.
    • Considerations
      • Understand contaminant.
      • Water reactives require special decontamination.
  • Mass decontamination
    • Emergency decontamination on large numbers of people.
    • Goal is to remove contaminants quickly to reduce health effects of a chemical exposure.
    • The difference between mass decontamination and emergency/field decontamination is the number of people involved.
  • Technical Decontamination
    • Planned and systematic process of reducing contamination to a level that is as low as reasonably achievable.
    • May involve several stations or steps and takes place in a defined area inaccessible to non- contaminated people.
  • Gross decontamination
    • Takes place as soon as possible within a controlled area.
    • Involves prewash and mechanical removal of the contaminant from tools, equipment, PPE, or vehicles.

Emergency/Field Expedient Decontamination

  • Quickly reducing or removing the bulk of contaminants through immediate action.
  • Separate as much of the contaminant as possible without a formal and detailed decontamination process.
  • Remove clothing, then douse with water.
  • Establish an area to isolate the exposed victims and protect water sources from runoff.
  • A fire engine can be used with a booster line or other small handline.
  • SDS should be located and sent with victim.
  • Ensure responder safety first and avoid touching contaminated victims and/or entering contaminated environments without the proper level of protection.

Summary

  • The first priority for all responders is to ensure their own safety while operating at the scene.
  • Hazardous materials/WMD incident response priorities should be based on the need to protect and/or reduce the threat to life, property, critical systems, and the environment.
  • To have some frame of reference for the degree of harm a substance may pose, responders should have a basic understanding of some commonly used toxicological terms and definitions.
  • Gather information from detection and monitoring devices, bystanders, reference sources, and environmental conditions to obtain a clear picture of the incident.
  • Exposures can include people, animals, property, structures, or the environment—anything that is subject to influence, damage, or injury because of contact with a hazardous material/WMD.
  • Tactical control objectives include preventing further injury and controlling or containing the spread of the hazardous material.
  • Response objectives should be measurable, flexible, and time sensitive; they should also be based on the chosen strategy.
  • The decision to act at a hazardous materials/ WMD incident should be based on the concept of risk versus benefit.
  • The type of PPE required for an incident depends on the material involved, any specific hazards, the physical state of the material, and the tasks to be performed by the operations level responder.
  • The selection and use of chemical-protective clothing may have the greatest direct effect on responder health and safety.
  • Respiratory protection is so important that it can be viewed as the defining element of PPE.