It might seem odd that two inspectors visiting the same sitewould come to opposite conclusions. However, that is exactly whathas been happening in southern California after the Station forestfire. Both inspectors take samples. Inspector A identifies"significant smoke particles," whereas Inspector B finds "carbon< 1%, which is not significant." This article is an attempt toexplain how such differences could occur.

Both inspectors performed scientifically respectable tests, yettheir results are polar opposites. Conditions after California'sStation forest fire were often misleading, but before getting intothat we should review a few basic concepts for testing.

The Purpose Should Be Clearly Defined

If the objective of a test is not clearly defined, then thesampling media, procedure, and tests performed on those sampleswill lead to conclusions that may prove irrelevant to the questionat hand.

For example, testing after a typical residential kitchen fireconsists of finding smoke particles by simple observation. Whereobservation is not conclusive, the adjuster, contractor, orproperty owner may take wipe samples with a cellular sponge,absorbent paper, or a similar medium. The contrast visible on thewipe or the target surface indicates whether that area requireswork. This is not high technology, yet the results of wipe testingare almost universally accepted after building fires.

In another situation, black particles appear with no apparentcause. Are they bacteria, candle smoke, or perhaps tobacco? In thiscase, the testing must identify the composition of the particles inorder to characterize their source. The targets of both tests areparticles, but the tests are distinctly different. If the samplingand tests for the two situations were reversed, then neither wouldprovide the answer needed.

All Evidence Should Be Considered

Even though the test of choice may be regarded as precise anddefinitive, other evidence can affect the result. Visual evidence,other procedures, testimony of observers, and site conditions maymodify the original test rationale. Good science requires that allrelevant information be considered. Therefore, test results shouldrelate to the real world, not to a narrow slice of information.

The Station Fire

With these considerations out of the way, let's consider thesituation in southern California. The Station fire burned out ofcontrol for several weeks in the autumn of 2009, consuming tons oftrees and vegetation. It was one of the largest fires in Californiahistory. Individuals who experienced the forest fire smokedescribed an atmosphere darkened by smoke, with particlespermeating building interiors. To resume normal life, residentsbegan to clean the smoke particles, in some cases enlistingprofessional help.

Large particles continued to appear long after the fire wasextinguished. It became clear that in many homes a single cleaningwould not resolve the problem. Some cases report smoke particlesare still appearing months after the fire, carried by prevailingwinds.

Smoke damage is a covered peril in most homeowners' policies. Amultitude of insurers responded to smoke damage claims from theStation fire by covering the cost of remediation, usuallycalculated as the cost of professionally cleaning the building andcontents. However, in some cases the insurer has required testingby a Certified Industrial Hygienist (CIH) to confirm that smokedamage occurred. The sampling and test procedures of some CIHs haveconsistently found that the percentage of carbon in their sampleswas below a 1-percent threshold and thus did not qualify assignificant damage. The origin of the 1-percent threshold isunclear. Even so, the insurer denies coverage by that evidence.

Does Incursion of Forest Fire Particles Constitute aLoss?

There exists no scientific definition of loss as itrelates to buildings or personal property. An assessmentof loss requires human interpretation. The loss may be inappearance, utility, value, life expectancy, or similarquality.

In the case of smoke, there is general agreement that combustionparticles are usually present in all buildings. This "normal"concentration will vary with the building's location, maintenance,and the activities of its occupants; however, it can usually beestablished within an order of magnitude by comparison withunaffected sites.

When a claim is filed, the insurer must determine whether acovered loss has occurred. When the claim is one of thousands froma forest fire, the cause is easily established. Determining theextent of the loss may require inspection of the site. Weeks ormonths may have passed since the fire, and cleaning of the buildingand contents has probably been performed repeatedly. Under thesecircumstances, what tests are appropriate? For our purposes, wewill refer to these as Tests A through D, as outlined below:

A. One that establishes the current particle level at thesite?

B. One that determines the chemical composition of particles insamples taken at the site?

C. A test that relates the quantity of carbon to the quantity ofother substances present in the sample?

D. A test that portrays the actual level of combustion particlespresent at the time of the loss?

Returning to the opening paragraphs, testing should answerrelevant questions. In this case, the question is whether aninsurable loss occurred and if so, the extent of that loss. Withthe Station fire, black particles continued to appear afterward, socontinual cleaning was performed. Therefore, conditions at the timeof the inspection (Test A) are irrelevant. Insurance relates to theconditions immediately following the loss, not weeks or monthslater.

Most people would agree that a sudden appearance of blackparticles is not normal and departs unmistakably from theconditions present a day earlier. The particles are clearlyvisible, they darken impacted surfaces and transfer to hands andclothing. Ingestion of the particles is detrimental to health.Furthermore, smoke particles are potentially corrosive toelectronic components, wiring, and decorative metals. So labor andmaterials must be expended to restore a livable, non-destructiveenvironment.

Is the chemical composition of those black particles relevant?In the absence of an alternative source for the sudden incursion ofblack particles during a forest fire, how can the sourcebe reasonably questioned? Under those conditions, any reasonableobserver would acknowledge the forest fire as the source of theblack particles, so the chemical analysis of Test B isirrelevant.

Test C relates the quantity of chemical carbon present in thesample compared to the quantity of other substances contained inthe sample, expressed as a percentage. How can the impact of smokeparticles relate to other materials that may be present? Thequantity, size, and mass of smoke particles present is an absolutequantity, not a dependant variable. If no other materials werepresent, then those smoke particles would comprise 100 percent ofthe sample. So if half were present, the same quantity of particles(or carbon) would become 50 percent of the sample. How can the samequantity of smoke particles constitute different percentages? TestC must therefore be considered both immaterial and misleading.

The final choice, Test D, portrays the actual level ofcombustion particles present at the time of the loss. How can werecreate the smoke particles after repeated cleaning has beenperformed? It is not necessary to create the particles, only tofind them. Every house contains crannies, soffits, and ledges thatescape normal cleaning, especially when the occupants areattempting to contain an ongoing problem. If samples areconsciously taken from those unobtrusive surfaces, then would theynot represent the distribution that occurred at the time of theforest fire?

What Test Methods Are Appropriate?

Thus far, we have avoided naming the various tests to which thesampling techniques are directed because their names are long,complex and intimidating. There is Energy Dispersive X-raySpectrometry, Polarized Light Microscopy, Epi-reflected LightMicroscopy, Transmission Electron Microscopy, and Scanning ElectronMicroscopy, Gas Chromatography/Mass Spectrometry. Despite theirportentous names, these tests can be grouped by function into a fewcategories: chemical analysis, quantitative analysis, and visualanalysis.

With the exception of optical microscopy, these highlysophisticated devices have a single purpose: to identify thecomposition of a sample and quantify its components. We havealready established that combustion particles deposited during anactive forest fire render further identification futile, as thecause is obvious. Nevertheless, these tests share anothercharacteristic: they convert the smoke particles into a differentphysical state, then analyze the modified substance and providesome sort of rating for the various components.

This is analogous to taking a cubic foot of snow, melting it,and analyzing the inch of water that remains. After forest fires,we are concerned with smoke damage, not elemental carbon. Likesnow, smoke particles have bulk, yet are extremely light. Theytravel for miles on air currents. Their significance lies in theirappearance and behavior as smoke particles, not as elementalcarbon. Ignoring the reality of smoke particles in favor of asophisticated carbon analysis is disingenuous, especially when itleads to conclusions that ignore reality.

A method of analysis that is frequently overlooked is simplereflected light microscopy. At appropriate magnification of 100X to200X, a clear image of smoke particles and background materials isimmediately available. Particle size and intensity can be opticallymeasured.

What Sampling Methods Are Appropriate?

There are many ways to sample particles. If airborne pollutantsare the target, then air samples can be taken with calibratedvacuum pumps and collected on a filter. If the chemical compositionof particles is the target, then wipe samples or vacuum samples maybe taken. Wipe samples collect materials by moving a collectionmedium across the target surface. This collection method destroysthe original form of the particles when the medium is flushed witha solvent and made suitable for the testing device.

A lift sample consists of a section of clear sticky tape whichis pressed onto a target surface then lifted and adhered to a glassslide or other medium. The lift sample retains the smoke particlesin their original configuration along with the other materialspresent. This is not a representation, but the actual physicalpresence of the particles, granules, fiber fragments, hair, dander,and other materials.

Tests answer questions. Analysis of smoke particles after theStation fire must answer the question of whether those particlesconstituted a loss. Testing is not required to identify thechemical composition of the particles because there is nodifficulty establishing their source. They appeared suddenly whensmoke from a forest fire inundated the community.

Establishing if a real loss occurred is contingent upon whetherthe quantity of the smoke particles was sufficient to diminish theappearance, utility, or life expectancy of the property. That isthe only question. The answer is available from microscopicexamination of samples representing conditions at the time of theloss.

In my role as damage investigator, I have analyzed hundreds ofsmoke samples over the years with reflected light microscopy. Theresults of these analyses have helped restoration contractors,property owners, and insurers determine whether significant smokeparticles were present in electrical systems, electronic controls,paintings, statuary, and historic objects.

The corrosive effect of untreated smoke particles has been wellestablished. Unfortunately, the misuse of legitimate test methodshas enabled some insurers to deny the significance of potentiallycorrosive combustion particles and other aspects of smoke damage.When knowingly used to avoid payment of smoke damage claims, thispractice is both reprehensible and dangerous.

Martin L. King, ASA, CR, is a technical advisor for theRestoration Industry Association in the area of fire damagerestoration and is principle investigator for Martin ChurchillAssociates. He has testified as an expert witness ininsurance-related litigation and frequently acts as arbitrator ininsurance disputes. In addition, King is the author of the RIAGuidelines for Fire & Smoke Damage Repair and has publishedmore than 300 articles in various trade journals.