Chapter 31: Hazardous Materials: Scene Safety and Control 12
Pre-Lecture
I. You Are the Fire Fighter
Time: 5 Minutes
Small Group Activity/Discussion
Use this activity to motivate students to learn the knowledge and skills needed to ensure rescuer and civilian safety at a hazardous materials incident through scene safety practices and procedures and by access control procedures, including the establishment of operating zones.
Purpose
To allow students an opportunity to explore the significance and concerns associated with maintaining scene safety and control of a hazardous materials incident.
Instructor Directions
1. Direct students to read the “You Are the Fire Fighter” scenario found in the beginning of Chapter 31.
2. You may assign students to a partner or a group. Direct them to review the discussion questions at the end of the scenario and prepare a response to each question. Facilitate a class dialogue centered on the discussion questions.
3. You may also assign this as an individual activity and ask students to turn in their comments on a separate piece of paper.
Lecture
I. Introduction
Time: 5 Minutes
Slides: 1-6
Lecture/Discussion
A. Scene control, site management, and personal accountability are critical.
B. Safe handling of hazardous materials incident determined in the first five minutes.
II. Levels of Damage
Time: 30 Minutes
Slides: 7-16
Lecture/Discussion
A. There are different ways to classify the point at which a hazardous material begins to affect an average, healthy person.
1. This point is called the threshold limit value.
2. Threshold Limit Value/Short-Term Exposure Limit (TLV-STEL)
a. Maximum concentration that a person can be exposed to in 15-minute intervals, up to four times a day, without experiencing chronic or irreversible tissue damage
b. Implies a minimum one-hour rest period between exposures.
c. The lower the TLV-STEL, the more toxic the substance.
3. Threshold Limit Value/Time Weighted Average (TLV-TWA)
a. Maximum concentration that a person could be exposed to eight hours a day, 40 hours a week, with no ill effects
b. The lower the TLV-TWA, the more toxic the substance.
4. Threshold Limit Value/Ceiling (TLV-C)
a. Maximum concentration that a person could be exposed to, even for an instant
b. The lower the TLV-C, the more toxic the substance.
5. Threshold Limit Value/Skin (TLV-S)
a. Indicates that direct or airborne contact could result in a possible and significant exposure by absorption through the skin, mucous membranes, and eyes.
b. Intended to suggest that appropriate measures be taken to minimize skin absorption so that the TLV/TWA is not exceeded
6. Permissible Exposure Limit (PEL)
a. Also called the Recommended Exposure Level (REL)
b. Comparable to the TLV/TWA
c. Maximum, time-weighed concentration to which 95% of healthy adults can be exposed over a 40-hour workweek without suffering adverse effects
7. Immediately Dangerous to Life and Health (IDLH)
a. An atmospheric concentration of any toxic, corrosive, or asphyxiant that poses an immediate threat to life or could cause irreversible or delayed adverse health effects
b. Three types of IDLH atmospheres:
i. Toxic
ii. Flammable
iii. Oxygen-deficient
c. Individuals exposed to atmosphere concentrations at or above IDLH levels must use SCBA or equivalent protection.
d. Below IDLH levels, most healthy individuals could escape the atmosphere without respiratory protection without irreversible damage to their health.
B. Determining Atmospheric Safety
1. Measuring atmospheric concentrations of chemicals requires specific training and equipment.
2. Exposure guidelines help minimize the possibility that responders and the public will be exposed to hazardous materials or atmospheres.
3. Three types of atmospheres at a hazardous materials emergency:
a. Safe atmosphere: No hazardous materials effects exist; no specialized PPE is needed.
b. Unsafe atmosphere: A hazardous material is present and creates an unsafe condition or atmosphere; exposure could result in acute or chronic injury.
c. Dangerous atmosphere: Exposure to the atmosphere will result in serious, irreversible injury, or death.
III. Personal Protective Equipment
Time: 30 Minutes
Slides: 17-34
Lecture/Discussion
A. Selection of Proper PPE
1. Standard structural firefighting PPE will not protect the fire fighter against many hazardous materials.
2. Adequate PPE should protect the fire fighter’s respiratory system as well as all the other parts of the body.
3. PPE for hazardous materials incidents must be selected based on the specific properties of the hazardous materials involved and on the properties of the product-specific suits.
4. The fire fighter must know what protection is offered by turnout gear when product-specific chemical suits are unavailable.
5. The incident commander should approve the level of PPE to be used on an incident.
6. Fire fighters should not use PPE that they have not been trained to use.
B. Types of personal protective equipment include:
1. Clothing and work uniforms
2. Structural firefighting protective clothing
3. High temperature-protective clothing
4. Chemical-protective clothing and equipment
C. Clothing and Work Uniforms
1. Offers no protection from hazardous materials
D. Structural Firefighting Protective Clothing
1. Offers almost no chemical protection
2. Easily absorbs materials, breaks down when exposed to chemicals, and does not provide protection from harmful gases, vapors, liquid, or dusts that may be encountered
E. High-Temperature Protective Clothing
1. Offers protection from high temperatures only and is not designed to protect against hazardous materials
F. Chemical Protective Clothing and Equipment
1. Designed to prevent chemicals from coming in contact with the body and may have varying degrees of resistance
2. Chemical-resistant materials
a. Designed to inhibit or resist the passage of chemicals into and through the material by the process of penetration, permeation, or degradation
3. Important Concepts
a. Penetration
i. The flow or movement of a hazardous chemical through closures, seams, porous materials, pinholes, or other imperfections
ii. Liquids are most likely to penetrate material.
iii. Some solids (e.g., asbestos) can penetrate some protective clothing materials.
b. Permeation
i. The process by which a hazardous chemical moves through a material at the molecular level.
ii. Permeation implies the chemical going through the material itself, rather than through an opening in the material.
c. Degradation
i. The physical destruction or decomposition of a material due to chemical exposure, general use, or ambient conditions (e.g., sunlight).
ii. Usually evidenced by signs such as charring, shrinking, swelling, color changes, or dissolving
iii. Materials can also be tested for weight changes, loss of tensile strength, etc.
4. Garment Construction
a. Single-piece
i. Completely encloses wearer
ii. Known as an encapsulated suit or acid suit
b. Multi-piece
i. Works with the wearer’s respiratory protection, an attached or detachable hood, gloves, and boots to protect against a specific hazard
5. Materials used in construction
i. Butyl rubber
ii. Tyvek
iii. Saranex
iv. Polyvinyl chloride (PVC)
v. Vitron
6. Liquid splash-protective clothing
a. Protects skin and eyes from chemical splashes
b. Does not provide total body protection from gases or vapors
c. Should not be used for incidents involving liquids that emit vapors
d. May be worn over or under structural firefighting clothing
7. Vapor-protective clothing
a. Must be used when hazardous vapors are present
b. Traps heat and perspiration so users and support personnel must be aware of possible heat-related emergencies
c. Must be used in conjunction with respiratory protection
G. Respiratory protection
1. Positive-pressure self-contained breathing apparatus
a. SCBA
i. Prevents exposure through inhalation or ingestion
ii. Should be mandatory for fire service personnel
iii. Fire fighters should know the limitations of SCBA
2. Supplied-air respirators (SAR)
a. User is connected to an external air source by a hoseline that connects to the facepiece
b. May be useful during extended operations
i. Decontamination
ii. Clean-up
iii. Remedial work
c. Hoseline may restrict movement
3. Air-purifying respirators (APRs)
a. Filter particulates and contaminants from the air
b. Should only be used in atmospheres where the type and quantity of contaminants is known and where there is sufficient oxygen for breathing
c. APRs do not have a separate source of air
i. APRs filter and purify ambient air before it is inhaled.
ii. Ambient atmosphere must contain a minimum of 19.5% oxygen.
d. Limitations:
i. Filtering cartridges are contaminant-specific.
ii. Continuous atmospheric monitoring is essential for safety.
IV. Chemical-Protective Clothing Ratings
Time: 20 Minutes
Slides: 35-38
Lecture/Discussion
A. Level A Protection
1. Fully encapsulating suit envelops both wearer and SCBA
2. Highest level of protection
a. Effective against vapors, gases, mists, even dusts
3. Requires respiratory protection using SCBA or SAR
4. Recommended PPE includes:
a. SCBA or SAR
b. Fully encapsulating chemical-resistant suit
c. Inner chemical-resistant gloves
d. Chemical-resistant safety boots/shoes
e. Two-way radio
5. Optional PPE includes:
a. Coveralls
b. Long cotton underwear
c. Hard hat
d. Disposable gloves and boot covers
B. Level B Protection
1. Consists of chemical-protective clothing, boots, gloves, and SCBA
2. Used when the type and atmospheric concentration of identified substances require a high level of respiratory protection but less skin protection
3. Type of gloves and boots worn depends on the chemical involved
4. Wrists and ankles must be properly sealed to prevent splashed liquids from contacting the skin.
5. Recommended PPE includes:
a. SCBA or SAR
b. Chemical-resistant clothing
c. Inner and outer chemical-resistant gloves
d. Chemical-resistant safety boots/shoes
e. Hard hat
f. Two-way radio
6. Optional PPE includes:
a. Coveralls
b. Disposable boot covers
c. Face shield
d. Long cotton underwear
C. Level C Protection
1. Consists of standard work clothing plus chemical-protective clothing, chemically resistant gloves, and some form of respiratory protection
2. Appropriate when the type of airborne substance is known, its concentration is measured, the criteria for using an APR is met, and skin or eye exposure is unlikely
3. Recommended PPE includes:
a. Full-face APR
b. Chemical-resistant clothing
c. Inner and outer chemical-resistant gloves
d. Chemical-resistant safety boots/shoes
e. Two-way radio
f. Hard hat
4. Optional PPE includes:
a. Coveralls
b. Disposable boot covers
c. Face shield
d. Escape mask
e. Long cotton underwear
D. Level D Protection
1. Level D is the lowest level of protection.
2. Should be used when the atmosphere contains no known hazard and when work functions preclude splashes, immersion, or the potential for unexpected inhalation of or contact with hazardous levels of chemicals
3. Level D PPE should be used for nuisance contamination (like dust) only.
4. Recommended PPE includes:
a. Coveralls
b. Safety boots/shoes
c. Safety glasses or chemical-splash goggles
d. Hard hat
5. Optional PPE includes:
a. Gloves
b. Escape mask
c. Face shield
V. Skin Contact Hazards
Time: 10 Minutes
Slides: 39-42
Lecture/Discussion
A. Principal dangers of hazardous materials are toxicity, flammability, and reactivity.
B. Hazardous materials can also harm the inadequately protected human body.
C. Assume the worst and leave the largest possible safety margin, especially when dealing with unknown chemicals.
D. The skin can absorb harmful toxins without any sensation to the skin itself.
1. Do not rely on pain or irritation as a warning sign of absorption.
2. Some hazardous materials are lethal if only a few drops contact the skin.
E. Skin absorption is enhanced by abrasions, cuts, heat, and moisture.
F. The rate of absorption depends on the part of the body contacted.
1. For example, chemicals can be absorbed through the skin on the scalp much faster then through the forearm
2. High absorbency rate of eyes make them one of the fastest means of exposure.
G. Corrosives do not have to be absorbed to damage the body.
1. Acids have a strong affinity for moisture and can cause significant burns to the respiratory tract
a. Acid burns are often self-limited by the formation of a clot-like barrier that blocks deep skin penetration.
2. Alkalis (bases) turn tissue into a soapy liquid as they burn.
a. Alkali burns are often deeper and more destructive then those of acid.
VI. Safety Precautions
Time: 30 Minutes
Slides: 43-55
Lecture/Discussion
A. General Introduction to Characteristics of Safety Precautions
1. In addition to standard safety precautions for operating at the scene of any emergency (i.e., PPE and respiratory protection), fire fighters must remain vigilant to dangers posed by temperature and stress.
B. Excessive Heat Disorders
1. Fully encapsulating and chemical-protective suits do not “breathe” (i.e., allow heat and perspiration to vent).
a. Fire fighters operating in such suits are at greater risk for heat-related emergencies.
2. Heat Exhaustion
a. A mild form of shock caused by overheating when the body is unable to dissipate heat.
b. Signs and Symptoms:
i. Elevated core temperature
ii. Weakness
iii. Profuse sweating
iv. Dizziness
v. Blurred vision
vi. Rapid, shallow breathing
vii. Weak pulse
viii. Cold, clammy skin
ix. Possible loss of consciousness
c. Emergency Action:
i. Remove the victim from the source of the heat
ii. Rehydrate
iii. Provide cooling
3. Heat Stroke
a. A severe and potentially fatal condition resulting from the total failure of the body’s temperature-regulation capacity
b. Caused by exposure to the sun or high temperatures
c. Signs and Symptoms:
i. Reduction or cessation of sweating
ii. Body temperature at or above 105ºF (40.5°C)
iii. Rapid pulse
iv. Hot skin
v. Headache
vi. Confusion
vii. Unconsciousness
viii. Possible convulsions
d. Emergency Action:
i. This is a true medical emergency requiring immediate transport to a medical facility.
4. Prevention of Heat-Related Emergencies
a. Fire fighters should prehydrate by drinking 8 to 16 ounces of water before donning any chemical-protective clothing.
b. Fire fighters should rehydrate with 16 ounces of water for each SCBA cylinder used.
C. Cold Temperature Exposures
1. Two types of cold exposure: materials-related and weather-related
2. Materials-related
a. Liquified gases and cryogenic materials can expose fire fighters to extreme cold.