December 1, 2019 Vol. 2, No. 12

Sifting the Ashes

It has been more than two years since the fire at Grenfell Tower in London claimed 72 lives and injured more than 200 people. The first volume of the report, covering over 900 pages and focusing primarily on the actions of the London Fire Brigade, has drawn harsh criticism as reported in the New York Times. The Times story is here:

https://www.nytimes.com/2019/10/30/world/europe/grenfell-tower.html?smid=fb-nytimes&smtyp=cur&fbclid=IwAR06DnRbzqQV4wr9pOloksFWgl9QsM356PXxKsnwsog98X4YJ68WpYIvBto

The criticism stems from the fact that the real culprits in this tragedy were the authorities who allowed the installation of combustible foam plastic cladding on the exterior of the 24-story apartment building. This turned a relatively fire safe structure into a very large candle. Volume 1 of the report, however, dwells extensively on errors made in fighting the fire. Certainly, the report points out opportunities for improvement in the handling of high-rise fires but hopefully Volume 2 will focus squarely on those actually responsible for the disaster. The Times story contains links to the actual report.

Lithium ion batteries

 (An excerpt from Scientific Protocols for Fire Investigation)

The greatest strength of lithium ion batteries is also their greatest weakness. The chemistry of the Li-ion cell allows a battery to be constructed that has an extremely high energy density, being measured in the range of .93–2.34 MJ/ Liter. By way of comparison, a conventional lead-acid battery has an energy density of .54 MJ/Liter, and a battery of Ni Cd construction has an energy density of .18 to .52 MJ/Liter. In designing battery systems, engineers try to use   a topology that allows the most energy to be packed into either the lowest volume (volumetric energy density) or lowest mass (gravimetric energy density). When the operation of a given cell is well controlled, the battery system is very reliable. However, when a given cell is operated outside its usual parametric envelope (to include external insult or internal manufacturing defect), the uncontrolled discharge of energy can result in extreme temperatures, flame, or both. Li-ion batteries do not respond well to either overcharging or undercharging [1]. Although there are exceptions for large applications (airplanes and automobiles), the phone, computer, and appliance batteries that an investigator is likely to encounter are either a set of “18650” cells or pouch-type batteries. These batteries, examples of which are shown in Figure 1, contain charge controllers and safety devices in addition to the chemical cells that provide the current.

As the use and fielded population of lithium ion batteries increases, even if the battery technology’s failure rate (estimated at 1 in 10 million cells) remains constant, the likelihood of an investigator encountering a lithium ion battery failure and fire statistically increases simply because the population of such battery-powered devices continues to grow over time. Manufacturers know what causes Li-ion batteries to fail

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Figure 1. A single 18650 cell (left) and a lithium ion pouch battery of the type used in tablets, laptops, and cell phones (right). (Courtesy of Richard Vicars, Jensen Hughes, Baltimore, MD.)

(Figure 2) and are taking steps to design safer ones. One new design uses a nonflammable electrolyte, an obvious risk reducer. Solid electrolytes are also on the horizon. Another design incorporates fusible microspheres of polyethylene. When the temperature in the cell reaches the melting point of the polymer, the now-liquid plastic seals the pores in the separator, shutting down flow of electrons. Although there will be safer designs in the future, today’s fire investigators must deal with the ones currently in service.

The failure modes of Li-ion batteries can be seen before a fire, but afterward, the cell where the failure started is likely to be so totally destroyed that not much can be said, other than, hopefully, “This is the cell that failed.” The ensuing fire may damage adjacent cells to the point where all that can be said is “This battery pack failed.” Thus, as with so many issues in fire investigation, the chicken-and-egg question arises. “Was this battery pack the cause of the fire, or did the fire damage the battery pack?” In some cases, both questions may be answered in the affirmative.

Figure 3 shows a hoverboard fire that occurred when the lithium ion cells, while being charged, went into thermal runaway.

Figure 2.  Diagram showing the various failure mechanisms for Li-ion batteries. (Reprinted with permission from Bruning, A., Why Lithium-Ion Batteries Catch Fire, Chem. Eng. News, November, 14, 2016, 94(45), 33. Copyright 2016 American Chemical Society.)

Any time a lithium ion–powered device is the suspected cause of a fire, a fire investigator

must work diligently to harvest all of the components. This includes finding all of the constituent pieces of the battery cells—cans, end  caps, straps, copper jelly roll, and so on, or pouches, chargers, and the battery management circuit boards. To avoid spoliation, special attention must be given to the harvesting and storage of the steel cans of 18650 cells as the cans quickly rust, corrode and ultimately disintegrate in evidence containers not properly prepared. As such, the optimum method of harvesting and storing these cans for long-term storage prior to a laboratory evidence exam is in a sealed container   with a desiccant package (Figure 4).

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Figure 3.    Remains of a hover board that ignited while being charged. (Courtesy of Richard Vicars, Jensen Hughes, Baltimore, MD.)

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Figure 4.    Proper method for harvest/storage of lithium ion cells. (Courtesy of Richard Vicars, Jensen Hughes, Baltimore, MD.)

Reference

[1] 1. Jordan, J. (2012) Batteries under fire, Fire and Arson Investigator 63(2):12.

Podcast on Lithium Ion Batteries

Jason Sutula, principal fire protection engineer at Jensen Hughes, and Bob Hafner, partner in Goldberg Segalla’s Product Liability practice, discuss fire investigations involving lithium ion and lithium polymer batteries. The pair detail what causes these products to fail, as well as innovative developments to mitigate the propensity and effects of failure. Additionally, Jason and Bob delve into the evidence collection process, tips for mitigating exposure to liability following a fire, and how a quick response can be dispositive for insurance industry professionals and product liability practitioners. Here is a link to a 24-minute podcast on the subject.

http://timelynotice.libsyn.com/lithium-ion-battery-fires

American Fire: Love, Arson and Life in a Vanishing Land

American Fire by Monica Hesse (Liveright 2017) describes the investigation and ultimate capture of two frustrated lovers who committed more than 80 arsons in 2012 and 2013 on Virginia’s Eastern Shore. It does not contain a lot of technical details about fire investigation, but instead describes the dogged determination of the fire investigators and other law enforcement officers who came to Accomack County to make the arsons stop.

One interesting aspect is the role of profilers brought in to help with the case. It turns out they were just as helpful as they were in the Washington sniper case where the perpetrator was described as “most likely a white male in his 30s.” Each of the fires were determined to be arson based on the fact that there was no power to any of the structures. Is it still a “negative corpus” determination if there are 80 of them?

The book is carefully researched and richly annotated, and reminds us of what good journalism looks like. Once I picked it up, I found it hard to put down.

https://www.amazon.com/American-Fire-Love-Arson-Vanishing/dp/1631494511/ref=sr_1_1?crid=3CYDKRX8PB680&keywords=american+fire&qid=1574696724&s=books&sprefix=American+Fire%2Caps%2C154&sr=1-1

Case Study of the Month

Domingue v. Imperial Fire & Casualty

and

Domingue v. Louisiana State Police Crime Lab

A perfect storm of errors almost leads to a horrible miscarriage.

Over the years, I have categorized the kinds of errors that can take place in fire investigation. This ability to categorize errors is the result of having seen quite a few botched cases. This month’s case study involves overlooking critical data, and faulty chemistry.

The Domingues headed off to church on Sunday morning between 10:15 and 10:30 and returned home to find the fire department at their house. A neighbor had seen smoke coming out the front door at 11:05, so there were 35 to 50 minutes available for the fire to burn. Fire investigators were on the scene while the fire was still smoking.


																				
Fire damage in the closet

Figure 1. Origin of the fire in the front hall closet.

The fire damage was all confined to a single closet in the front hall (Figure 1), so origin determination was not all that difficult. The closet door was closed, resulting in underventilation and in the production of a pungent smelling smoke, so the first investigators, from St. Tammany Fire Protection District #1, used an electronic sniffing device, which alerted them to the possible presence of ignitable liquid in the closet.

According to the homeowners, there was a rechargeable Electrolux vacuum cleaner in the closet, plugged into the outlet in the closet, but it was so badly damaged that the first investigators could not identify the pieces. The rechargeable vacuum cleaner was under a CPSC recall at the time of the fire. On April 7, the insurance company sent an electrical engineer to the site but he collected no evidence and did not even disassemble the receptacle where the vacuum cleaner had been plugged in. He reported that the fire was undetermined due to removal of evidence but there was “no unusual low burning, accelerant pour patterns or any other evidence of the fire having been incendiary in origin.” He did conclude that examination of the receptacle revealed no electrical arcing or shorting and showed its damage to be the result of an external fire.” The electrical engineer also concluded that the homeowners stated that among the items stored in the closet with a battery-powered portable vacuum cleaner, which was plugged into the receptacle at the time of the fire. The vacuum cleaner represents a reasonable and possible accidental electrical cause of the fire.”

The investigators submitted a single sample to the Louisiana State Police Crime Laboratory, collected on the basis of the “odd odor” and the positive response of the electronic hydrocarbon detector. It was collected the day of the fire but not submitted to the crime laboratory until April 21, about three weeks after the fire. The laboratory issued its report on May 13, which stated, “Analysis of Exhibit 1 revealed the presence of gasoline.”

The fire department investigators concluded on May 18, “Based on the results from the crime lab, this fire is determined to be arson.”

Once the arson determination was made, the investigation was turned over to the St. Tammany Parish Sheriff's Department, who interviewed the Domingues. One of the observations made by the sheriff’s investigator was neither the homeowner nor his wife displayed the emotions expected of them and they for the most part were calm given the loss they had just encountered.

Investigators were also concerned at the time frame of the fire, being 35 to 50 minutes. According to them, this was “too fast” for a fire with an electrical cause.

The receptacle is shown in Figure 2.

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Figure 2. Fire Department image, showing evidence of a flame-shaped pattern directly behind the receptacle.

On December 27, seven months after the fire, the electrical engineer prepared a supplemental report and stated “the findings of the State Police and St. Tammany Parish Sheriff that gasoline was identified and unaccounted for in the closet is consistent with an incendiary fire that was caused by the deliberate actions of an individual or individuals.”

The homeowners did submit to an interview, but when it became clear to them that they were suspects enough in an arson case, they ceased cooperating. The Sheriff's office closed their file because they were unable to determine who had set the fire: the homeowner, his wife, or one of the children. The Domingues thus dodged the criminal bullet, but their insurance company was resisting the claim.

Counsel for the homeowners retained Craig Balliet of Barker and Herbert laboratories to review the chemical analysis conducted by the State Police laboratory and concluded there was something strange about this sample of gasoline. Mr. Balliet concluded in a report dated March 25, 2011, “My opinion is a gasoline or gasoline residue is not present in Exhibit 1.” This was based on the extremely low level of alkanes in the sample. It is known that residues that meet most of the criteria for gasoline but do not contain alkanes may be a residue of an aromatic solvent rather than gasoline.

Confronted with this potential problem in the chemical analysis, the insurance carrier retained Doug Byron of Forensic and Scientific Testing, who reviewed the data and Mr. Balliet's report and concluded in a report dated May 19, 2011, that the low levels of alkanes were not a problem and that the sample met the criteria set forth in ASTM E 1618 for gasoline.

The case proceeded to civil litigation, and the deposition of the state’s chemist was taken on May 26, 2011.

I was not aware of this case until almost two years later when Mrs. Domingue contacted me after doing some Internet research on misidentified gasoline. She had learned about my analysis of the chemistry in the Lime Street fire. http://www.firescientist.com/Documents/NewOrder/1992%20The%20Lime%20Street%20Fire%20Ray%20Powell,%20John%20Lentini,%20John%20DeHaan.pdf

I looked at the chemistry data and decided that, despite the low level of alkanes, it was probably gasoline but saw no other evidence that the fire was incendiary. Specifically:

1. None of the investigators observed fire patterns on the closet floor indicative of a flammable liquid burning there.

2. Had gasoline been poured on the closet floor and ignited, it would be expected that the floor of the closet would have exhibited such patterns.  The floor and the baseboards were generally unburned.

3. Although non motor fuel uses for substances that meet the criteria for gasoline are uncommon, it is known that some household products, notably insecticides, do contain such substances.

        

4. The hinges of the closet door were found in the closed position. Most people know that a fire needs oxygen.

5. There was a 35 to 50-minute interval between when the Domingues left the home and the fire’s discovery.  Gasoline-fueled fires tend to burn rapidly.  That is the whole point of using gasoline.

6. There is no evidence that any items were removed from the home in anticipation of the fire.

7. There is no evidence that anyone had prior knowledge of the fire.

8. The timing of the fire, 11 AM on a Sunday morning, is not at all typical of incendiary fires, which are often set at night in order to delay discovery.

9. No evidence of motive has been developed.  The Domingues were building another home at the time of the fire, but they have continued to pay their notes on both houses.

My report stated that the evidence was consistent with a fire starting at the receptacle based on the following:

1. The Romex cables in the stud space directly above the receptacle leading to the receptacle box are heavily charred, while the cables in the adjacent stud space and elsewhere in the closet still retain their original shape and are light in color.

2. The receptacle box is heavily burned from the top down, suggesting a fire inside the box burning upward.

3. The second layer of drywall, located immediately behind the receptacle box, has begun to char, as shown in Figure 2. There are no similar fire patterns elsewhere.

I was deposed by the insurance company’s lawyer on July 19, 2013. He was unimpressed and decided that this case was going to trial. The Domingue’s lawyers decided that they did not need me as a witness. It was during the preparation for the trial that the truth came to light.

As the state’s chemist was preparing to testify in the trial in early 2014, she reviewed her deposition transcript and realized that she had made an error  (“misspoke”) when she testified in 2011 about the procedure that she used in the laboratory. It seems that the laboratory had recently instituted new procedures that included running negative control samples (blanks) between each questioned sample, a procedure designed to demonstrate a lack of “carryover” or cross-contamination. The new procedure was instituted shortly after she analyzed the Domingue sample, but her testimony indicated she had used it. She also remembered that there was another sample, submitted on the same day by the same fire department, that exhibited the curiously low level of alkanes. Because of this uncertainty, the chemist requested and received samples from both cases, the one sample from the closet, and the other strong sample that exhibited low alkane content. In each can there was a “reserve strip” prepared so that retesting was possible without the necessity of retesting the actual samples.

Much to her surprise, when she retested the reserve strip from the closet sample, it did not test positive for gasoline. The reserve carbon strip from the other strong sample continued to test positive.

The chemist knew that one possible explanation for the discrepancy would be that the samples strips had been mixed up when they were first analyzed. She did not want to admit that, however, and wrote in a February 2014 affidavit that the data from the samples indicated that the initial carbon strips from the sample analysis in 2010 could not have been mixed up because the data from the reserve samples did not match. This is exactly a false conclusion. If the reserve strips don’t match, there has been a mix-up. The chemist, however, speculated that there may have been evaporation from the reserve strip allowing it to change over time.

In my experience, this doesn't happen. In fact, every time I have retested a reserve strip, it has been identical to the original strip. The reserve strip was sealed in a vial which was sealed in a nylon pouch. Here is the paragraph that explains the “logic” behind the chemists reasoning: “However, what was observed in the data cannot be explained by the lab. The data from the sample in this case indicated no ignitable liquids were detected in the reserve carbon strip. The data from the other sample in question indicated that gasoline was detected. This laboratory has no prior experience with the re-examination of sample carbon strips that have been stored under unknown conditions for approximately 3.5 years, thus, we cannot make conclusions as to whether gasoline would have been retained on the strip, or could have evaporated over time.”

Because of the uncertainty about the integrity of the chemical analysis, the insurance company tendered policy limits and the case went to trial in the summer of 2014 on the issue of bad faith. The jury decided that because they had been provided with a positive report by the State Police Laboratory, the insurance company was not acting in bad faith when they denied the claim.

During the trial, the fire investigator testified that he now finds the original results of the fire debris analysis prepared by the crime lab to be unreliable.  He stated that the supplemental report and affidavit of the chemist, provided him “with a level of doubt that he is very uncomfortable with,” and that he considers it “scary” that someone could have been convicted based on faulty evidence.    

I was provided with both the affidavit and a copy of the chemist’s trial testimony in July 2014, after the trial, and I must say that upon reading this chemist’s “explanation” I was incensed. Not only did the explanation have no credible basis, both the sample and the reserve strip were destroyed after the retesting, allegedly based on the chemist’s misunderstanding of the potential for future retesting. I surely did look like a cover-up.

Having not been made whole by the court, and knowing full well that they did not start the fire, the Domingues sued the Crime Laboratory. The State pleaded sovereign immunity and a host of other defenses, claiming that the lab was merely negligent and could not be held liable for the error. During the pendency of that litigation I prepared an affidavit dated December 14, 2017, describing the chemist’s error and the faulty explanation for the reserve strip not testing positive. I stated that “The most (in fact the only) likely explanation for the discrepancy between the test results obtained from the initial test which show the presence of gasoline, and the results of the retest conducted on the reserve strip which was negative for gasoline, is that the chemist mixed up the strips either by putting the strip from the closet sample in the wrong vial or by putting the vial in the wrong auto sampler spot.” I went on: “The chemist’s failure to openly admit that the most likely cause of the discrepancy between the samples was her own error, particularly where there was a pending criminal investigation and insurance claim, was scientifically unethical and fraudulent. Having discovered such a critical error, and ethical scientist would have recognized a professional obligation not to participate in the trial.” This was at the end of 2017. The crime laboratory had moved for summary judgment, and my affidavit was prepared in support of a motion to deny the motion for summary judgment. The motion was denied.

The litigation continued well into 2018. I was notified that the case had settled on June 1, and that the Domingues had at last, eight years after the fire, been made whole.

Error Analysis

One is tempted to absolve the local fire investigators for believing the laboratory analysis, but that analysis did not fit with the rest of the data. Faced with such a situation, it makes sense to ask for a retest. The investigators knew that they had received similar results from two samples submitted at the same time from different fires.

The fire investigators committed a serious error by not taking the time to identify the remnants of the rechargeable vacuum cleaner. They were told it was in the closet, and they should have sifted the contents of the closet to find the pieces. If they could have shown that it was not present, their case would have been stronger, but simply giving up on looking for it was not the way to go. The electrical engineer clearly identified it as a potential ignition source, and the brand was under recall as a fire hazard.

The recall, which affected 320,000 units was issued in March 2009. A year later, when I filed a FOIA request, Electrolux managed to prevail on the CPSC to withhold much of its investigative data because the CPSC staff did not personally investigate each of the fires. I did find one case of overheating and on case of injury caused by an exploding lithium-ion battery. The fire investigators were unaware of the recall.

The main responsibility for this fiasco, however, lies with the chemist at the State Police Crime Laboratory and her management. There was a question about the gasoline from the beginning, and there is no question that the gasoline had an unusual composition. While the chemist stated in 2014 that she only retested the samples because she was aware of “misspeaking” during her deposition, this is not a highly credible assertion given that she was put on notice immediately that the gasoline had an unusual composition.

We are all human and we all make mistakes. In forensic science, as in just about every field of human endeavor, it is true that the cover-up is worse than the crime. I have made my share of mistakes in the last 45 years, and I have found that the best thing to do is to embrace the error and address it sooner rather than later. By the time the chemist realized her mistake, the Domingues had already endured four years of suspicion with potential criminal liability involved. Her affidavit reads like a denial and she certainly was in denial. What is surprising is that the laboratory management went along with this non-explanation and speculation about evaporation.

Significance

This case has two important lessons.

First if the puzzle doesn't fit together right, try another angle, or to quote NFPA 921, “If the hypothesis is refuted or not supported, it should be discarded and alternate hypotheses should be developed and tested. 

Second when you discover a mistake, own it and own it quickly. NIST has for the last several years sponsored conferences on dealing with errors in forensic science. They are an opportunity for improvement. Take a lesson from the medical profession. Dr. Donald Berwick, one of the pioneers of the modern patient safety movement stated, "Every defect is a treasure." Learn from your mistakes. Don't bury them.


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We have a new vendor for the book, The Fire Fighter’s Bookstore and they are offering a 20% discount off the publisher’s list price. Go to:

https://www.firebooks.com/products/scientific-protocols-for-fire-investigation-3rd-edition?_pos=8&_sid=3b6cfbbf2&_ss=r

For information about setting up a 3-day course at your facility that uses the book as a “handout,” contact me directly at scientific.fire@yahoo.com

Next issue

This is the 18th monthly edition of Sifting the Ashes. Due to increasing commitments over the next few months, I will be changing to a quarterly schedule.  Look for the next edition in April.

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