炭疽事件環境消毒案例

Anthrax Sent By Mail September / October 2001

Anthrax Attacks What Happened

4-5 letters containing anthrax spores sent in mail

4 regions initially affected in USFloridaNew York / New

JerseyWashington MetroConnecticut

Mild contamination of other US postal facilities

Nationwide Effects Threats Concerns

18 human cases in US11 inhalation

(5 deaths)7 cutaneous33,000 + people

prophylaxed

Cleanup

Remediation Alternatives were developed through both existing and new

relationships inside EPA and DOD.

Remediation Methods for Daschle Suite

Evaluation Time Limited by Extreme Pressure to Re-enter BuildingMethods Evaluated Were:

–Chlorine Dioxide - Liquid and Gas–Para-Formaldehyde–Ozone–Hydrogen Peroxide–Sandia Foam–Bleach

Chlorine Dioxide Selected

Chlorine Dioxide breaks down rapidly reducing residual risksNo breakdown products of concern are formedUsed in other areas of commerce effectively and safely

Hart Remediation PlanInitial Concept: Fumigate entire building using ClO2 gasPeer Review: > 20 organizations

* ClO2 appropriate technology* Don't try entire building

Revised Plan* Fumigate Daschle Suite only* Sample all other suites in Hart by following

the mail trail

Cleanup Goal

CDC unable to define a “safe level" for Anthrax* Experts believe that there is a

“safe level"* No health studies * Impacts on sensitive populations unknown

Risk management decision* Cleanup = No detectable growth of Anthrax

spores

Cross-Contamination Cleaning Approach

• Extent of Contamination

• Isolate the Area • Select a Cleanup

Method

• “Sandia” Foam• Liquid Chlorine

Dioxide

Daschle Suite

• Very High Spore count • Fumigation of entire suite with chlorine dioxide• Fumigation of HVAC System• Removal of materials• Cleaning with aqueous chlorine dioxide• Efficacy sampling with spore strips• Post cleanup sampling (PCR & cultures)

Daschle Suite Fumigation

December 1 - 2, 2001Suite Sealed and Spore Strips DistributedSteam Piped in to Provide HumidityClO2 Introduced and MaintainedMonitoring Inside and Outside SuiteClO2 Evacuated and Spore Strips CollectedVerification Sampling Initiated

Chlorine Dioxide Generator

ClO2 Sampling Manifold

9th Floor Negative Air Unit

Negative Air Setup

Negative Air Line

Hart Senate Office BuildingHVAC Chlorine Dioxide

Fumigation - (January 2002)

HVAC Situation

• Bacillus Anthracis contamination of return air duct system of the HVAC

• Supply side of HVAC uncontaminated

• Duct and mechanical system difficult to access by “conventional decontamination methods”

• Vertical and Horizontal surfaces

HVAC Remediation Alternatives

• Conventional Duct Cleaning (vacuum, liquid application)

• UV Oxidation (with or without sonic)• Various Decontaminating Foams• Vapor Hydrogen Peroxide• Gaseous Fumigation (several options)

HVAC Challenges

• Stakeholder interests• Time limitations to accomplish remediation• Isolation of the HVAC system• Design and construction of fumigation equipment• Efficacy, operational, and air quality monitoring• Finite qualified manpower resources• Contractor and agency coordination• Public safety considerations

Major Remediation Equipment• 2 ClO2 generator stations feeding 4 ClO2

stripper columns.• 3 ClO2 stripper column sites feeding 13

injection points.• 2 Steam supply points feeding 13 injection

points.• 10 ClO2 gas sample points feeding

centralized manifold in Hart garage with analytical equipment.

• 14 remote temperature and humidity points with data cables feeding a centralized command center in Hart garage.

• 7 Spore strip sites containing a total of 428 spore strips.

• ERT and TAGA support.• On-site analytical laboratory.

ClO2 Stripper Towers (Emitters)• PVC construction• Received ClO2 liquid from storage

tote• Compressed air stripped ClO2 gas

from liquid• Spent liquid recycled to ClO2

generator and or totes• Supplied ClO2 gas via tubing to

injection points• Pressure, temperature, air flow, and

stripping efficiency monitored• No moving parts

HVAC System Sample Ports

ClO2 Scrubber Tower

• Located on the 9th floor• PVC construction• Received ClO2 fumigation air via

double contained ducting from NAU exhaust

• Utilized alkaline sodium sulfite scrubbing solution misted into air stream

• Treated air vented into building atrium

Onsite Analytical Lab

• Located in the Hart Garage in close proximity to data management and operational monitoring

• Provided real time ClO2concentrations

• Analysis provided by amperometric titration (wet chemistry) methods

Personnel Required• EPA = 6• Capitol Police = 12+• AOC = 8• Sabre Oxidation = 8• Kemron = 8• IT = 7• CDM = 3• Lockheed Martin = 4• Tetra Tech = 12• HMHTTC = 6• EMT = 4• UOC = 1

TOTAL: 80+

HVAC Fumigation Results• Temperature parameter achieved.• Humidity parameter achieved in 5 of 6 critical locations.• ClO2 ppmv concentration parameter inconsistently

achieved.• ClO2 ppmv – hrs CT parameter achieved in 5 of 6 critical

locations.• Spore strip dosimeter array data suggest FDA standard

for pervasive sterilizing sporicidal effects (106 Bs kill and 105 Bs kill) was achieved during the fumigation.

• Post-fumigation environmental and air sampling suggest that the ClO2 fumigation was successful in remediating the spore burden within the HVAC system.

ReoccupancyAssistant Physician For Capitol

* Sought CDC AdviceRoom By Room Review Performed

* EPA & CDC* Evaluated Sampling & Cleanup

Aggressive Air Sampling Req'dResult: Joint Agency Sign-off Recommending Reoccupancy

* Building By Building

Health and Safety

Dealing with a deadly bacterial spore, our health and safety training took on

a new and serious dimension.

Health & Safety Provisions

Aggressive Medical Monitoring• Attending Physician of the Congress

Prophylaxis• Ciprofloxacin• Doxycycline

Health & Safety Provisions (con’t)

Personal ProtectionQuantitative Fit TestsDouble Suiting

Decontamination• Triple Chamber Wet Decon• Stabilized Bleach in Decon

Suiting up in Level A outdoors

Cl O2 Monitoring in Level A

Modified Level C with PAPRs and Duct Taped Seams

Open Decon Line

Door of 3 Chamber Decon

Sampling and Culturing

Sampling Plans

• NIOSH and EPA• Bacterial Indicator Spores• Each sample includes one PCR (polymerase

chain reaction) test and two cultures (morphologic and DNA)

• Data Management

Sampling Methods• Wipe sampling• Swab sampling• Gel samplers• Biotest samplers • Dry Filter Units (DFU)• Aggressive air sampling

technique• High Efficiency Particulate

(HEPA) vacuum sampling

Extensive Sampling Effort

Characterization Samples: 3,402Verification Samples: 1,556Other Samples: 207TOTAL SAMPLES: 5,165

Spore Strips: ~ 4,500

Wipe Sampling

Wipe Kit

HEPA Kit

Swab Kit

HEPA Vacuum

HEPA Vacuum Sampling

Aggressive Air Sampling

DFU Placed in Daschle Suite

Gel Sampler

Bio Test Kit

Post Cleanup Restoration by the AOC (Carpet, Ceiling Tiles, Painting, etc)

Hart Building Reopens1/22/02

Senator Daschle Returns to Hart

Command structure issues–No model for legislative branch role in cleanupWho's in charge?Complex ICS established

–Police incident: Limited public and media interaction

–Fear of perception of unequal treatment versus USPS?

Anthrax Lessons Learned

Anthrax Lessons Learned II

Impossible schedule demands for completing the workThree month project: planned and implemented as a series of two week projectsCredibility lost due to blown schedulesHard to argue with people so powerful

Anthrax Lessons Learned III

Resources stretched to limit2 - 12 hour shifts/day - 7 days/week for 3 months at multiple locationsRequired ~10 OSCs a day & significant support from other regions/organizationsContractor support impacted by other Anthrax events nationally

Anthrax Lessons Learned IV

Unique health & safety issues Contractors weren't properly fit tested - EPA filled roleMedical monitoring effort had to consider antibiotics & vaccinesExtended period before level C was accepted as adequate for worker protection

Anthrax Lessons Learned VEarly coordination with states is criticalDisposal is complicated by perceptions & fears [NIMBY]Off-site treatment can generate similar concernsStates can supplement lab capabilities/capacitiesUnique state resources can be identified (ie. mine rebreathers)

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