pu 430 unit 6 chapters 4 and 9. chemical disasters chapter four
TRANSCRIPT
PU 430PU 430Unit 6
Chapters 4 and 9
Chemical Disasters
Chapter Four
Background: Recent Chemical Background: Recent Chemical Warfare Agents Terrorist Warfare Agents Terrorist EventsEvents
1993 World Trade Center Bombing
1995 Aum Shinrikyo sect released Sarin vapor into Tokyo Subway
Basic Facts about Chemical Health Threats
Chemical toxicity
Response
Dose
Dose–response relationship
Chemical agentsChemical agents
Range from warfare agents to toxic chemicals commonly used in industry.
Criteria for determining priority chemical agents include◦chemical agents already known to be used as
weaponry◦availability of chemical agents to potential terrorists◦chemical agents likely to cause major morbidity or
mortality◦potential of agents for causing public panic and
social disruption◦agents that require special action for public health
preparedness
Source CDC
Routes of Entry
Inhalation
Skin/mucous membrane absorption
Ingestion
Injection
Chemical Exposure Factors
The route & rate of an exposure determines the dose received. The results can include:◦Acute poisoning - a rapid absorption resulting
in an especially fast & severe response◦Chronic poisonings - result from prolonged
exposures over a longer period of time ranging from days to years
There are a variety of factors that determine poisoning outcomes
Exposure Factors
DoseTime of exposureRoute of ExposurePhysical characteristics of chemical
substancePrevious or simultaneous exposures to
other chemical substancesEnvironmental conditionsPhysiological characteristics of the
exposed
CWA CharacteristicsCWA Characteristics
Volatility◦Tendency to evaporate from liquid to gas form◦Greater volatility= shorter persistence
Vapor Density◦Weight of the vapor or mist relative to air◦All CWA’s (except HCN) heavier than air
Persistence◦Most evaporate > 24 hours◦Present increased risk for skin exposure to
victims and risk to responders
How do we prepare public health How do we prepare public health agencies for chemical attacksagencies for chemical attacks
Globally Harmonized System (GHS) of Human Health Classes
Includes 10 classes of chemical threats to human Health
Is being implemented in the U.S. but requires a tremendous effort
Although the implementation of this system is necessary, it will come with a substantial learning curve for nations that have firmly established practices
Communicating Hazards: NFPA Fire Diamond
NFPA “Fire Diamond”
Nomenclatures: Chemical CategorizationThere continues to be fundamental differences in the
nomenclature of various hazards
CDC lists them by category: http://www.bt.cdc.gov/agent/agentlistchem-category.asp
Chemical Accidents versus Terrorism
Chemical Terrorism The most likely chemical terrorism scenarios are also the
most likely industrial accident scenarios
Chemical Accidents Chemical accidents are preventable & with the knowledge,
tools, & regulations that exist in the U.S., these incidents should be exceptionally rare
Prevention
Community Prevention Activities EPCRA (“List of Lists”) - This document lists the chemicals required to be
reported by industry to local & state officials LEPCs - Carry out preparedness activities at the community level SERC – Maintained by each state to appoint members & establish
jurisdictional areas for each LEPC
Reducing Building Vulnerability High-risk facilities need to complete a comprehensive vulnerability
assessment of their AHU & ensure a detailed risk reduction plan is developed & implemented.
Home Prevention Activities In the home, many household products are accumulated that individually
or combined can pose a risk to residents
Immediate Actions
Individual Response
Healthcare Response
Public Health Response
General Treatment GuidelinesGeneral Treatment Guidelines
Nerve Agents◦ Atropine, pralidoxime chloride (2-PAMCl), or diazepam
Incapacitating Agents◦ Remove to fresh air, decon w/water, 6% bicarbonate solution
Pulmonary Agents◦ Supplemental oxygen, restrict physical activity, medical attention
Vessicants/Blister Agents◦ Remove to fresh air, remove clothing, decontaminate skin,
supplemental oxygen, hospitalization, extensive irrigation of eyes
Blood Agents◦ Amyl nitrate, sodium nitrate, sodiumthiosulfate
Prehospital Care and Prehospital Care and DecontaminationDecontaminationFirst responders: Respirators, goggles,
protective clothingSelf-contained breathing apparatus
(SCBA) is recommended in response to any nerve agent vapor or liquid.
Butyl rubber gloves (most agents are lipophilic)
20% of healthcare workers in Tokyo had mild symptoms after taking care of patients. These symptoms included nausea, eye pain, and headache.
Prehospital Care and Prehospital Care and Decontamination (continued)Decontamination (continued)
Inhalation exposure
Dermal
Ingestion
Psychological ImpactPsychological Impact
Psychological impact ◦Examples
Post traumatic stress disorder
Fear and depression
Sleep disturbances
Recovery Actions
Once a chemical emergency is over, residents of the affected area should:◦Not reenter the area until local authorities
announce that it is safe to return◦Thoroughly ventilate the structure by
opening all windows & turning the air handling systems on
◦Avoid any potentially contaminated food or water
◦Watch for household hazardous materials◦Never smoke or initiate any open flames
Nuclear & Radiological Disasters
Chapter Nine
Basic Facts about Nuclear & Radiological Threats
A Nuclear Event Distinguished by a nuclear detonation or
fission
A Radiological Event Does not involve a fission reaction or
nuclear explosion
Possible ScenariosPossible Scenarios
Nuclear power plant incidentHidden source“Dirty bomb” Improvised nuclear deviceNuclear weapon
Exposure vs. ContaminationExposure vs. Contamination
Exposure: irradiation of the body absorbed dose (Gray, red)
Contamination: radioactive material on patient (external) or within patient (internal)
Nuclear & Radiological Health Threats
Acute Radiation Syndrome (ARS) It includes four stages:
◦ Prodromal stage - can begin within minutes or days of the exposure & last up to several days & includes gastrointestinal symptoms such as nausea, vomiting, & diarrhea
◦ Latent stage - the patient will feel fine for a period of time ranging from hours to weeks
◦ Manifest stage - includes one or more of three classic syndromes◦ Final stage - either recovery or death
Cutaneous radiation injury (CRI) There is usually a delay between the exposure & the onset of
symptoms & the progression is in stages There is a prodromal, latent, & manifest illness stage,
sometimes followed by a third wave before recovery
Injuries Associated with Injuries Associated with Radiological Incidents Radiological Incidents
Acute Radiation Syndrome (ARS)Localized radiation injuries/ cutaneous
radiation syndromeInternal or external contaminationCombined radiation injuries with - Trauma - Burns Fetal effects
Skin EffectsSkin EffectsSkin EffectsSkin Effects
NUREG / CR-4214, p II-68NUREG / CR-4214, p II-68
EpilationEpilation ErythemaErythema PigmentationPigmentation Dry desquamationDry desquamation Moist desquamation Moist desquamation
that healsthat heals
EpilationEpilation ErythemaErythema PigmentationPigmentation Dry desquamationDry desquamation Moist desquamation Moist desquamation
that healsthat heals
Patient DecontaminationPatient Decontamination• Remove and bag the patient’s
clothing and personal belongings (this typically removes 80 - 90% of contamination)
• Handle foreign objects with care until proven non-radioactive with survey meter
• Survey patient and collect samples- Survey face, hands and feet- Survey rest of body
Nuclear & Radiological Accidents versus Terrorism
There are five distinct differences:◦ Most radiological emergency planning is focused on
accidents that are much smaller events & would not include the same hazards
◦ Due to the alarm systems in place, most accident scenarios will have several hours of warning before a release begins
◦ Most nuclear reactors are located in rural areas where fewer people & less infrastructure will be affected by an accident
◦ The management of an emergency at a nuclear facility is likely to be much better coordinated
◦ The type of radiological material involved in a nuclear facility accident is likely to be different from what would be seen with the IND or RDD attack
Prevention
Nuclear Non-Proliferation Treaty (NPT) ◦Expresses support for nonproliferation of nuclear weapons programs, disarmament, & peaceful use of nuclear technologies for energy & other peaceful applications
◦Has been signed by 189 nations over the past 30 years
Immediate Actions
With radiological events, the principles are well understood &
there are fewer unknowns:◦ The detection instrumentation is ubiquitous, dependable, & quick to use◦ The ability to predict those at risk & offer recommendations is much
more straightforward than other threats There are four broad scenarios that should be considered during
planning so the proper actions are incorporated into preparedness activities:◦ A transportation accident involving radiological materials◦ An accident at a nuclear facility ◦ The RDD or dirty bomb with the explosion of a package or a vehicle
carrying radioactive materials ◦ A small IND that could appear like the September 11, 2001 attacks on
the U.S. with a block or several blocks of buildings as “Ground Zero”
Public Health & Protective Actions
The primary roles of public health agencies in the aftermath of a nuclear or radiological incident
Protective Action Guides (PAGs) include recommendations for the general public & separate recommendations for first responders
There are recommended initial actions for the general public for the time prior to the availability of radiological measurements & associated protective action guidance.
Psychological CasualtiesPsychological Casualties
Terrorist acts perceived as very threatening
Large numbers of concerned with no apparent injuries
Mental health professionals should be included
For more information on radiation exposure and pregnancy
www.bt.cdc.gov/radiation/prenatalphysician.asp
Dealing With Staff StressDealing With Staff Stress
Preplanning
Establish information center
Train staff on radiation basics
Post Event
Debrief immediately after event
Offer Counseling
Medical Response
According to the Centers for Disease Control & Prevention, there are six areas that need to be considered by healthcare organizations as they prepare for nuclear & radiological incidents: ◦Notification & communication◦Triage◦Patient management◦Healthcare worker protection◦Surveillance◦Community planning
Unique Pharmaceutical Issues
The Strategic National Stockpile (SNS) has a variety of critical radiological pharmaceutical resources available to support a radiological incident response
Recovery
The only way to minimize the chronic social impact is to manage it well
from the moment it occurs, including the registration & close monitoring
of those truly at risk