Chapter 7

Fire Smoke: Responder Health and Safety

Objectives: Awareness Level Personnel and

Operations Level Responders (1 of 3)

• Discuss the hazards of fire smoke. • Identify different classifications of fire

gases generated during the typical combustion process encountered in various types of fires.

• Discuss the need for wearing respiratory protection during and after active firefighting.

Objectives: Awareness Level Personnel and

Operations Level Responders (2 of 3)

• Discuss the various technologies available for fire-ground detection and monitoring.

• Discuss general fire-ground monitoring principles and practices.

• Understand the need for prompt recognition and treatment of smoke inhalation.

Objectives: Awareness Level Personnel and

Operations Level Responders (3 of 3)

• Identify NFPA 473, Chapter 6.4, Mission-Specific Competencies Advanced Life Support (ALS) Responder Assigned to Treatment of Smoke Inhalation Victim, as a reference source for treating smoke-related illness and injury.

• Identify appropriate clinical interventions for treating smoke inhalation.

Introduction

• Anytime something burns, the combustion process liberates fire gases and particulates.

• Headache, nausea, dizziness, and fatigue are common signs and symptoms that can be traced back to breathing smoke from all types of fire.

Harmful Components of Fire Smoke (1 of 2)

• Carbon monoxide• Ammonia• Hydrogen chloride• Sulfur dioxide• Hydrogen cyanide• Carbon monoxide

Courtesy of Rob Schnepp

Harmful Components of Fire Smoke (2 of 2)

• The oxides of nitrogen• Formaldehyde• Acrolein• Polycylic aromatic hydrocarbons• Soot

Smoke Production

• Chemical makeup of the burning material• Temperature of the combustion process• Influence of ventilation (oxygenation)• Smoke is a collection of particulates,

superheated air, and gaseous chemical compounds.

Synthetic Manufacturing and Construction Materials (1 of 3)

• Extensive use affects fire behavior and smoke production.

• Synthetic substances ignite and burn fast, causing rapidly developing fires and toxic smoke.

Synthetic Manufacturing and Construction Materials (2 of 3)

• Polyurethane foam: most prominent substance in mattresses– When exposed to heat, parent substances

break down and bond with each other, creating new compounds.

– Some new compounds are irritants, including hydrogen chloride and ammonia.

– Other compounds, such as carbon monoxide and cyanide compounds, are acutely toxic when inhaled.

Synthetic Manufacturing and Construction Materials (3 of 3)

• The visible part of combustion: particulates or soot– Known human carcinogen

Polycyclic Aromatic Hydrocarbons (1 of 2)

• Commonly found in fire smoke• Probable or possible human carcinogen• Over 100 identified and categorized• Found in vehicle exhaust, tobacco smoke,

and smoke generated from structure fires, vehicle fires, wildland fires, and any other type of fire

Polycyclic Aromatic Hydrocarbons (2 of 2)

• Can exist as particle or gas• When generated during structure fire, may

bond with soot, resulting in dermal and inhalation exposures

• Contaminants to fire fighter bunk gear

Carbon Monoxide and Hydrogen Cyanide (1 of 3)

• Acutely toxic • Present to some degree in nearly all fires• Clinical interventions available to reverse

the adverse health effects of the exposure

Carbon Monoxide and Hydrogen Cyanide (2 of 3)

• Important determinants of smoke inhalation-related morbidity and mortality

• Cyanide concentrations directly related to probability of death

• Cyanide poisoning may be more predominant than carbon monoxide poisoning as cause of death in fire victims.

• May potentiate the harmful effects of one another

Carbon Monoxide and Hydrogen Cyanide (3 of 3)

• Hydrogen cyanide can incapacitate a victim, preventing escape from fire environment, thus increasing exposure to more cyanide, carbon monoxide, and other toxic byproducts of combustion.

Hydrogen Cyanide (1 of 2)

• Cyanide affects aerobic metabolism.– Red blood cells carry oxygen to and from cells.– Oxygen enters the mitochondria of each cell

where nutrients are converted into ATP molecules.

– Cyanide compounds absorbed in the body prevent oxygen from entering mitochondria, shutting down aerobic metabolism.

– Without oxygen, the cells switch to anaerobic metabolism, producing toxic byproducts, such as lactic acid, which destroys the cell.

Hydrogen Cyanide (2 of 2)

• Elevated lactic acid level is a key indicator of cyanide toxicity.

• Signs and symptoms of cyanide toxicity include headache, dizziness, stupor, anxiety, rapid breathing, and increased heart rate.

Carbon Monoxide• Carbon monoxide is one

of the most common industrial hazards.

• Colorless, odorless, and produced during incomplete combustion

• Affects oxygen-carrying capacity of red blood cells, causing hypoxia

Smoke Inhalation Treatment (1 of 2)

• Smoke inhalation is one of the most complex and challenging patient presentations faced by medical care providers.

• Patient outcomes influenced by:– Extent and duration of smoke exposure– Amount and nature of toxicants in smoke– Degree of thermal burns to skin and lungs– Quantity/size of inhaled particulates (soot)– Patient’s age – Underlying medical conditions

Smoke Inhalation Treatment (2 of 2)

• Until the underlying cause of asphyxia is reversed at the cellular level, normal oxygenation is not possible.

• Requires administering antidote (oxygen) to restore body’s ability to use oxygen

• High-flow oxygen should be administered for all cases of smoke inhalation.

Treating Cyanide Poisoning

• Lilly kit (also called Taylor or Pasadena kit) – Contains amyl nitrate, sodium nitrate, and

sodium thiosulfate– Can have adverse effects

• Cyanokit– Contains hydroxocobalamin– Benign, minimal adverse effects

Resource

• Consult NFPA 473, Chapter 6.4, Mission-Specific Competencies Advanced Life Support (ALS) Responder Assigned to Treatment of Smoke Inhalation Victim, as a reference source for treating smoke-related illness and injury.

Postfire Detection and Monitoring (1 of 2)

• There is no best practice for detection and monitoring in the fire environment.

• Atmospheric monitoring on the fire scene is important.

• Technology and devices should be user-friendly, durable, cost-effective, and easy to maintain.

Postfire Detection and Monitoring (2 of 2)

• Wearing SCBA is still the gold standard of respiratory protection and the best way to reduce possibility of inhalation exposures.

• Three primary uses for detection devices– Rescue response– Building collapse– CO detector responses

Initial Detection

• No single device can detect all the fire gases and particulates in fire smoke.

• Initial detection seeks to determine what substances you want to detect and/or monitor and at what concentrations these substances pose a risk of exposure.

Safe Levels for Chemicals in the Workplace (1 of 2)

• Immediately dangerous to life and health (IDLH)– Atmospheric concentration of any toxic,

corrosive, or asphyxiant substance that poses immediate threat to life or would interfere with an individual’s ability to escape from a dangerous atmosphere

– Levels at or above IDLH require use of breathing apparatus or withdrawal from area if no SCBA is worn.

Safe Levels for Chemicals in the Workplace (2 of 2)

• Short-term exposure limit (STEL)– 15-minute exposure no more than four times

a day• Recommended exposure limit (REL)

– 10-hour exposure

Detecting Fire Gases

• Most common method involves use of single-gas or multi-gas detection devices.

• Because one gas may not be an indicator of the level of airborne concentration across the entire scene, the next step is to widen the focus and evaluate for multiple gases.

Multi-gas Meter

• Configured with variety of sensors to detect:– Carbon monoxide– Hydrogen sulfide

Electrochemical Sensors (1 of 2)

• One of the most common technologies in postfire detection and monitoring

• Filled with chemical reactant that reacts with a target gas and results in a meter reading

• Toxic sensors react to other gases so you cannot be sure whether you’re reading a level of the intended gas or the interfering gas.

Electrochemical Sensors (2 of 2)

• Can be easily overwhelmed and will max out with regard to their readings

• Fail to the zero point• Responders should ensure devices are

calibrated properly and should be bump tested before use.

• Reaction time varies

Photoionization (PID) Sensor(1 of 2)

• Stand-alone unit or multi-gas meter• Uses ultraviolet light to ionize gases that

move through sensor• Detects organic materials• Ammonia: most common inorganic

chemical detected

Photoionization (PID) Sensor(2 of 2)

• Alerts user of presence of material, but doesn’t identify it

• Won’t detect CO or HCN or compounds such as natural gas

• Water resistant, not waterproof Courtesy of Rob Schnepp

Colorimetric Tubes

• Detect specific substances and/or confirm readings of other technologies

• Identify presence and/or levels of known gas or vapor and unidentified substances

• Air moves through tube by use of piston-style pump or bellows pump.

• Tubes are one-time use only; pump is reusable.

Fire Scene Detection and Monitoring Practices (1 of 3)

• Use of detection devices during active interior structural firefighting is not necessary.– High heat, particulates, and steam or water

detrimental to instruments• Assume environment is IDLH, and wear

firefighting PPE, including SCBA.• Air monitoring during active firefighting

should be limited to exterior operations.

Fire Scene Detection and Monitoring Practices (2 of 3)

• Detection and monitoring should start with general exterior evaluation of footprint of fire.– Work inward toward areas where crews are

operating.– Fire gas production stops only when all

substances involved in fire are cooled below point they decompose and off-gas.

– Initiate interior monitoring when all visible particulate has been ventilated from structure.

Fire Scene Detection and Monitoring Practices (3 of 3)

• Fire investigators should evaluate environment prior to beginning work.

Summary (1 of 13)

• U.S. Fire Administration fire death statistics for the United States report approximately 3000 fire-related deaths annually. That places the United States in the top 15 countries in the world for per capita fire deaths.

Summary (2 of 13)

• Like a scuba diver, a fire fighter initiating an interior attack at a working structure fire is completely enveloped by the operating environment. If a supply of breathable air is lost or interrupted, the environment invades the body, causing harm.

• The AHJ should establish reasonable and safe work practices for those responders working in, and possibly exposed to, fire smoke.

Summary (3 of 13)

• Think about all the places on the fire ground, outside of the interior of the structure, where fire personnel are repeatedly exposed to smoke.

• Cancer is prevalent in the fire service, more so than nearly any other profession. This should be no surprise once the byproducts of combustion are understood. A number of known human carcinogens are liberated as fire gases and particulates.

Summary (4 of 13)

• Smoke is a collection of gaseous products of burning materials—especially organic materials—made visible by the presence of small particles of incomplete combustion.

• Soot is a known human carcinogen, just like benzene and formaldehyde—also common byproducts of combustion.

Summary (5 of 13)

• PAHs are believed to be immunosuppressant, perhaps contributing to the mechanism by which PAHs are suspected to cause cancer.

• NFPA 1851, Standard on Selection, Care, and Maintenance of Protective Ensembles for Structural Fire Fighting and Proximity Fire Fighting, offers guidance on bunker gear cleaning and maintenance.

Summary (6 of 13)

• Carbon monoxide is one of the most common industrial hazards. It is colorless and odorless and produced during incomplete combustion.

• Cyanide compounds, once absorbed into the body, “poison” the cytochrome oxidase, barring oxygen from entering the mitochondria, effectively shutting down the process of aerobic metabolism.

Summary (7 of 13)

• Carbon monoxide reduces the amount of oxygen carried to the cells; cyanide renders the cells incapable of using whatever oxygen is present.

• Oxygen is the natural antidote for CO poisoning. In all cases of smoke inhalation, high-flow oxygen should be administered.

Summary (8 of 13)

• Hydrogen cyanide poisoning should be suspected in smoke inhalation patients with significant hypotension, soot in the nose or mouth, and/or an altered level of consciousness.

• It is important to understand that smoke inhalation is an illness just like congestive heart failure, asthma, or any other medical condition you may encounter in the field, and that aggressive clinical intervention is key to the possibility of a good income.

Summary (9 of 13)

• NFPA 473, Chapter 6.4, Mission-Specific Competencies Advanced Life Support (ALS) Responder Assigned to Treatment of Smoke Inhalation Victim, is a companion document to NFPA 472 that provides background to treating smoke inhalation patients.

Summary (10 of 13)

• Atmospheric monitoring has a place on the fire scene. The technology and devices used should be user-friendly, durable, cost effective, and easy to maintain, and the benefits and limitations of any instrumentation should be understood.

Summary (11 of 13)

• Because no single device will identify all possible toxins on the scene, it is important to know that targeting certain gases (CO and HCN as an example) may be broadly representative of the airborne environment, but not an exact indicator of the presence, absence, or concentration of any other gas or particulate in the air. Wearing SCBA is still the gold standard of respiratory protection and is the best way to reduce the possibility of inhalation exposures.

Summary (12 of 13)

• It is important to understand the limitations of post-fire detection and monitoring when a single gas is being targeted. A common misconception is this: if that single gas is found to be below the REL, the entire airborne environment is safe.

Summary (13 of 13)

• Regardless of the technology selected, responders should develop a strategy for the use of detection devices. There are no hard and fast rules for post-fire detection and monitoring, so the AHJ should develop some broad operational guidance.

• Detection and monitoring at the fire scene should be a highly mobile and continuous process.