wildfire residues assessment and restoration – a … - xavier alcaraz.pdfand restoration a case...

Xavier Alcaraz, MSPH, CIH, CSP Principal Consultant – BSI

March 7, 2019

Copyright © 2019 BSI. All rights reserved.

Wildfire Residues Assessment and Restoration – A Case Study of the 2017 NorCal Fires

Wildfire Trends

Wildfire Smoke – What is it?

AIHA – Technical Guide for Wildfire Impact Assessments

Sonoma County Wildfire Assessment

Restoration Plan

Post-Cleaning Verification

Lessons Learned/Recommendations

Questions/Answers

Overview

Copyright © 2019 BSI. All rights reserved. 2


Wildfire Trends

Potential Impact of Wildfires

• Loss of life• Property, environmental, and public health impacts• Smoke can travel great distances and deposit residues on surfaces• Airborne particulate matter is the primary pollutant of concern• Special concerns for susceptible populations:

― Infants and young children, individuals with chronic or pre-existing respiratory medical conditions, and pregnant women

• Investigations and clean-up can last weeks to months after a fire



Wildfire Smoke

Wildfire Smoke – What is it?• Particulates (ash, soot, char)• VOC (PAH, aldehydes, dioxins)• Corrosives• Metals


• Nitrogen oxides• Hydrocarbons• Carbon monoxide• Others

Wildfire Particulates

What are they comprised of?• Char: large irregular fragments of burned material• Soot: fine carbonaceous material• Ash: mostly decarbonized residue of cellulose material



AIHA – Technical Guide for Wildfire Impact

Assessments

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• Purpose: establish consensus• Spring 2018• Developed by SME

― EHS and IAQ― Analytical labs― Restoration

• Peer reviewed


Major Sections



• Impact of Wildfires• Wildfire Assessment• Sampling Techniques• Analytical Methods• Restoration Methods

Should Include:

Wildfire Assessment


• Relevant history of events• General construction basics of the property • Interior and exterior investigation of spaces

and surfaces― Observations (odor, visible/physical impact)

• Sampling (if necessary)• Knowledge of mechanical building ventilation/HVAC• Detailed documentation, maps indicating sampled areas, and photo/video

documentation

Pre-Entry Safety Considerations– the exterior should be inspected for structural fire damage

Wildfire Assessment


• Fire risk• Falling trees• Electrical hazards• Gas leaks• Animals• Personal safety

• Date(s) of wildfire occurrence• Name• Size of wildfire• Location and proximity of wildfire

relative to the property• Prevalent wind direction(s)• Occupant observations during the

wildfire• Ambient air quality monitoring station

data

Information Gathering/Occupant Interviews – relevant data prior to or during investigation

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Visual Inspection is very important

Wildfire Assessment


• Wildfire residue produces distinct visual cues of impact, which include the following:― Selective deposition/accumulation of

combustion related particles― Electrophoresis― Thermophoresis― Filtration marks/threshold streaks― Smoke webs and smoke chains/smoke tags― Corrosion― Olfactory


Sampling Techniques

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Sampling Strategy

Sampling Techniques


• Establish a hypothesis• Consider size of the subject property, points of entry and layout of the structure• Collect a sufficient number of samples of various types of materials (i.e., hard horizontal

surfaces, porous materials, fabrics, curtains, carpet, HVAC filters)• Factors affecting the sampling design include: collection efficiency, collection efficacy, medium

suitable for analysis, point sources, and representation of exposure

Sampling Techniques


• Particle sampling― Particles of most interest are products of

incomplete combustion of plant matter― Char, ash, and soot

• Sampling for volatile organic compounds (VOCs) and semi-volatiles (SVOCs) can complement particle sampling

• Methods:― Tape Lifts― Wipes― Micro Vacuuming

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Analytical Methods

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Fundamentals

Analytical Methods


• No standards or requirements for wildfire residues• Analyses should support study objectives • Generally includes determining the relative loading and composition of char,

ash, and soot particles• Useful in distinguishing alternative sources of combustion particles, accelerants,

and alternate sources of materials that might cause interferences in the analysis

• Ideally, a process that is both efficient in collection and easily processed for analyses is ideal

• Make sure to establish background/baseline levels to compare results

General Approach

Analytical Methods


1. Analysis of char, soot, ash and other fire indicator signature particles― Assemblage Analysis

2. pH and Conductivity Analysis3. VOC and SVOC Analysis

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Options may vary…

Analytical Methods


• Analytical Techniques:― Polarized light microscopy (PLM)― Transmission Electron Microscopy (TEM)― Scanning electron microscope (SEM) and electron dispersive X-

ray analysis (DEX or DES)― Fourier Transform Infrared Spectroscopy (FTIR)― Raman Spectroscopy― Gas chromatography/mass spectrometry (GC/MS) ― High-performance liquid chromatography (HPLC)

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Restoration

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The goal of wildfire residue clean-up/restoration is to return the property to a pre-fire condition

Restoration


• There are general clean-up guidelines from FEMA, CAL-EPA, OEHHA, Cal-OSHA, etc.

• Initial inspection should focus on surroundings for downed power lines and affected trees that may present a danger

• Walk around the perimeter of the structure, look for burned areas, charring, and warped/leaning exterior walls

• Inspect the roof for evidence of fire/heat damage• Ensure exit/entry doors function properly before

entering the structure― Signs of related structural damage include wood

charring, steel warping, spilling/cracking of concrete/masonry materials

Wildfire residue restoration involves a step-wise approach that includes all or some of the following:

Restoration


• Inspection of the property for structural heat/fire damages, accumulations of wildfire residue, and other fire-related damages

• Development of a cleaning and/or restoration scope and work plan based on inspection findings

• Removal and replacement of building components impacted by the fire

• Basic cleaning of wildfire residue impacted interior surfaces and contents

• Professional restoration of building materials and/or contents using specialized equipment and processes beyond basic cleaning

• A verification inspection by a qualified OEHS professional to assure that cleaning and/or restoration activities have resulted in successful removal of fire damages and odors

There is no single approach to cleaning that fits all wildfire impact situations

Restoration


• Conduct cleaning in a systematic manner to prevent cross-contamination

• Replace filters in heating/air conditioning system with higher efficiency filters to reduce recirculation of airborne wildfire particles

• Dry-sponge cleaning technique for smooth, non-porous finishes• Vacuuming with a High Efficiency Particulate Aire (HEPA) filter• Wet cleaning (indoor damp wiping or outdoor wet cleaning)

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Actions should include:

Post-Restoration Verification


• Review restoration scope and verify it was completed

• Perform visual inspection to verify cleaning was effective― White glove test

• Perform surface sampling• Reclean and repeat inspections/testing

where there are deficiencies


County of SonomaWildfire Residues Assessment

Background

• Northern California wildfires (North Bay Fires or Wine Country Fires) in October 2017

• Series of 17 fires across various counties (Napa, Lake, Sonoma, Mendocino, Butte, Solano)

• October 7-14• 245,000 acres burned• 90,000 persons evacuated• 44 killed, 192 hospitalized


Background

• The largest of the wildfires (Tubbs) and smaller fires (Nunns, Patrick, Atlas) were within close proximity to many Sonoma County properties

• November 7, 2017: County of Sonoma (County) Risk Management Division contacted BSI to request assistance with assessing the impact of their facilities from Northern California wildfires in October 2017

• BSI developed a wildfire residues assessment strategy for the County • November 9, 2017: BSI mobilized a field team to initiate assessments of

potentially impacted buildings


Project Purpose and Objectives• Purpose: Assess for wildfire-related residues on representative building

surfaces in County buildings to provide the County with data to support their facility-interior cleaning decision-making process

• Objective(s):1. Adopt a wildfire-related residues sampling and assessment strategy2. Test and inspect for signs of wildfire-related impact in representative County

buildings3. Determine if specialized cleaning (restoration) was necessary4. Develop restoration plans for each building requiring cleaning5. Verify cleaning was effective

Note: assessment was NOT designed to evaluate potential health impact or risk.Instead, it was designed to evaluate for abnormal levels of fire residues



Methods

Assessment Strategy – Visual Inspections

Visual inspections of occupied work areas for signs of wildfire-related impact including the presence of smoke-related odors, staining, and visible debris:• Tops of cubicle partitions, file cabinets, computer monitors• Tile flooring (corners of rooms where dust accumulates)• Select closets with HVAC ventilation (flooring and horizontal surfaces)• Rooms/offices with windows (horizontal surfaces and window sills)• HVAC diffusers (air supplies)• Ceilings around HVAC diffusers• HVAC Air handlers


Assessment Strategy – Surface SamplingSurface sampling of representative surfaces/areas within the buildings• Tape-lift sampling: clear adhesive tape (2”x1”) • Focus areas for surface sampling:

― Tops of cubicle partitions, file cabinets, computer monitors― Tile flooring (corners of rooms where dust accumulates)― Select closets with HVAC ventilation (flooring and horizontal surfaces)― Rooms/offices with windows (horizontal surfaces and window sills)― HVAC diffusers (air supplies) ― Ceilings around HVAC diffusers― HVAC air-handler surfaces (downstream of the primary filters, such as cooling coils)

• Samples submitted under chain-of-custody to an independent lab for analysis by Polarized Light Microscopy


Assessment Strategy – Site Selection• 800 County buildings considered for evaluation • 250 County buildings occupied either continuously or intermittently• Risk-based approach used to select and evaluate buildings for potential fire/smoke-

related impact• Risk-rank buildings based on the following criteria

― Proximity of the building to the fire and the potential exposure based on occupancy» Buildings within 5 and 10 miles of a fire perimeter» Occupancy duration (continuous, intermittent, occasional)

― Additional factors» Known smoke- or fire-related impact» Reported complaints of smoke- or fire-related odors, illness reports» Building structure risks (built prior to 1990, direct air pathways into the building)» Presence of sensitive populations (children, compromised health)


County Risk Assessment Map

Assessment Strategy – Site Selection


Wildfire Impact Risk Ranking Criteria for County Buildings



Distance From Fire Perimeter

OccupancyWithin 5 miles Within 10 miles Beyond 10 miles,

w/in valley Beyond 10 miles

Continuous High Medium Low Extremely Low

Intermittent Medium Low Extremely Low Extremely LowOccasional or None Low Extremely Low Extremely Low Extremely Low

Sampling Approach Based on Risk Ranking Criteria for County Buildings



Risk RankPercent (%) of Buildings to be Sampled

Sampling Approach

High 100% (80/80)Sample and inspect 100% of buildingSample 100% of air handlers at building

Medium 100% (74/74)

Sample 100% of building, but taking 50% fewer samples than high-risk locationsInspect 100% of buildingSample 75% all air handlers at building

Low20% (33/162)1) Targeted selection2) Random selection

Sample and inspect up to 20% of building, taking 80% fewer samples than high-risk locationsSample 20% all air handlers at building

Extremely Low <1% (6/485) No inspection or sampling required

Results


Regulations and Guidelines (November 2017)

• No regulatory standards or guidelines for testing and/or interpretation of wildfire-related residues

• AIHA publication on testing for wildfire residues not yet published • November 2017 edition of the American Industrial Hygiene Association

Synergist titled “The ABCs of Wildfire Residue Contamination Testing” by Alice Delia, PhD and Dan Baxter stated: ― “Although ‘normal’ proportions of fire to non-fire particles have not been thoroughly

defined or published, levels above approximately 5 percent likely indicate an increasing probability of fire residue contamination”

• Data interpretation table developed based on this publication and County’s risk tolerance


Data Interpretation Table


Percent (%) Area of Combustion Particles/Fire Residues

Interpretation (Likelihood of Fire/Smoke Impact) Proposed Action(s) Risk-Based Post-Cleaning Verification Approach

ND, Trace, 2%Normal Condition: ty pical of recently cleaned surfaces and/or building surfaces w ith minimal or no combustion residues detected.

None: If no obv ious smoke impact has occurred (v isual, reported, or sampling, no action required

None: No action required based on initial inspections, sampling results

3% - 4%

Low: minor presence of combustion residues detected which may be from v arious sources including fires. The presence of a combination of ash, soot and/or char increases the likelihood of fire/smoke impact.

Cleaning and Further Evaluation: action may be warranted based on ev aluation of sampling data and/or risk factors. A ction may consist of further testing, inspections, and/or cleaning. C leaning may be localized or expand to larger areas based on risk factors

Visual Inspection: v isually inspect all representativ e and specific areas/surfaces w ith prev iously identified surfaces warranting cleaning. Surfaces should be clean and free from v isible dust/debris.

5% - 10%

Moderate: moderate presence of combustion residues detected bey ond normal conditions. The presence of a combination of ash, soot and/or char increases the likelihood of fire/smoke impact.

Cleaning – Result warrants cleaning. Ty pe and extent of cleaning is based on the areas and surfaces represented by sample(s) and inspections.

Visual Inspection and Testing: v isually inspect all representativ e and specific areas/surfaces w ith prev iously identified surfaces warranting cleaning. Surfaces should be clean and free from v isible dust/debris. Test representativ e surfaces specific areas/surfaces w ith prev iously identified surfaces warranting cleaning.

V erification samples = 2x (# of Moderate-rated samples identified during initial assessment)

>10% High: high presence of combustion residues detected bey ond normal conditions.

Cleaning - Result warrants cleaning. Ty pe and extent of cleaning is based on the areas and surfaces represented by sample(s) and inspections.

Visual Inspection and Testing: v isually inspect all representativ e and specific areas/surfaces w ith prev iously identified surfaces warranting cleaning. Surfaces should be clean and free from v isible dust/debris.

Test representativ e surfaces specific areas/surfaces w ith prev iously identified surfaces warranting cleaning. V erification samples = 3x (# of High-rated samples identified during initial assessment)

General Observations• Initial testing completed in January 2018• No significant visible fire-related ash, soot, char observed within buildings• Of ~100 buildings tested, 17 buildings had sample results with high impact

ratings, 26 had sample results with Medium impact ratings• Above-normal sample results:

― Near windows that open― Near entrances to buildings (floors, door frames)― Top of furnishings and cabinets

• Few buildings tested had HVAC air handlers with above normal impact ratings • Restoration efforts initiated in March and completed in December 2018 (after

recleaning and re-testing)


Sample Lab Report


Results were entered into a database and assigned a “Fire Impact” rating

Sampling of Results


# of Buildings Location ResultTotal % Combustion Residues

Fire Impact Rating

XYZ building, Santa Rosa

Main door entrance next to toolbox top

Ash - 10Char - 2Soot - Trace

12% High

XYZ building, Santa Rosa

Parks office - staff work/break area desk

Ash - 5Char - 3Soot - Trace

8% Moderate

XYZ building, Santa Rosa Paint brush storage cabinet - inside

Ash - 3Soot - TraceChar - Trace

3% Low

XYZ building, Santa Rosa Paint brush storage cabinet - inside

Ash – 1%Soot - TraceChar - Trace

1% Normal

Restoration









3% - 4%




5% - 10%









Sample Restoration Plan









3% - 4%




5% - 10%









Lessons Learned and Recommendations


Recommendations

• Test your response plans (EAP, BCP, DRP, Claims Process, etc….) for feasibility under realistic scenario outcomes― Train and inform your staff so they are prepared

• Develop an IAQ plan before you need it• Get help from experienced professionals before you need it

― Restoration contractors― EHS Consultants― HazMat and HazWaste


Before a wildfire affects your area

Recommendations

• Keep windows and doors tightly closed ― Protect poor seals with wet rags, paper towels, etc.

• Put your HVAC in recirculation mode― Install double filters and/or carbon filters― Change filters when air pollution conditions improve

• Communicate to your key stakeholders• Contact and engage your support network• Engage your insurance carrier ASAP• Document, Document, Document


During and after a wildfire….

Additional Resources

• AIHA “Technical Guide for Wildfire Impact Assessments” Spring 2018• Cal-OSHA Worker Health and Safety in Wildfire Region

https://www.dir.ca.gov/dosh/Worker-Health-and-Safety-in-Wildfire-Regions.html• AIHA Disaster Response Center: https://www.aiha.org/publications-and-

resources/Pages/Disaster-Response-Resource-Center.aspx


https://www.dir.ca.gov/dosh/Worker-Health-and-Safety-in-Wildfire-Regions.html

https://www.aiha.org/publications-and-resources/Pages/Disaster-Response-Resource-Center.aspx

Special Thanks

• Heidi Fowers, MS, CSP – Risk Control Manager• Andrew Leman – Safety Analyst• Carina LaDelle – Safety Analyst



Thank You!

Xavier Alcaraz, CIH, [email protected](408) 790-9216 (office)(408) 835-3127 (mobile)


Questions?

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mailto:[email protected]

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