Sustained Combustion of Bodies: Some Observations*

Abstract: Previous tests have explored the fire effects and fuel characteristics of animal carcasses in intense fires of relatively short duration. Here, test fires were conducted involving intact human cadavers and torsos that included nonaccelerated, long‐duration fires involving the bedding and clothing (in the manner of typical accidental deaths). The objective was to observe the fire conditions (size, radiant heat flux, and duration), where a human body represented the major fuel package in a nonaccelerated fire. The pattern of damage to the body was documented and compared with that resulting from a furnished room fire. Two intact, unembalmed human cadavers were exposed to fires of simulated accidental origin. The bedding was ignited by an open flame, and the fires were allowed to burn unaided to self‐extinguishment. It was found that normal human bodies can support a modest‐sized fire for some 6–7 h under these conditions. The presence of a substrate material that can act as a wick for the combustion of the rendered body fat results in extensive destruction of the torso where the greatest amount of subcutaneous fat resides, with less damage to the head and limbs. A third (partial) cadaver was exposed to a recreation of a typical accidental fire in a furnished room that progressed to full room involvement. This fire of some 15 min of total duration inflected only surface‐layer damage to the torso of the victim.     

Combustion of animal fat and its implications for the consumption of human bodies in fires.

This paper describes experiments in which the combustion of animal tissue (pork) was measured under a variety of conditions that may be encountered in fire scenes. Combustion depends on substantial preheating of the tissue by an external heat source and the availability of a porous wick (such as charred cellulosic material). Combustion of moderate-size samples can proceed at a moderate rate of 1-3 g/s (3.6-10.8 kg/hr) if provided with an adequate wick and results in only a small fire of 30-50 kW. In the final test, combustion of 26 kg of fat and skin created a fire of 120-130 kW. Such a fire is more likely to cause fire spread to other combustibles nearby. The presence of other, less efficient fuels (like skin and muscle) and the absence of large fuel masses (such as in the very lean pig carcasses used here) results in significantly smaller fires of 40-50 kW. Such fires are more typical of burning human remains when there are minimal contributions from other fuels.     

Gasoline on hands: preliminary study on collection and persistence

The identification of an arsonist remains one of the most difficult challenges a fire investigation has to face. Seeking and detection of traces of gasoline could provide a valuable information to link a suspect with an arson scene where gasoline was used to set-up the fire. In this perspective, a first study was undertaken to evaluate a simple, fast and efficient method for collecting gasoline from hands, and to assess its persistence over time. Four collection means were tested: PVC, PE and Latex gloves, as well as humidified filter paper. A statistical assessment of the results indicates that Latex and PVC gloves worn for about 20 min, as well as paper filter rubbed on hands, allow an efficient collection of gasoline applied to hands. Due to ease of manipulation and to a reduced amount of volatile compounds detected from the matrix, PVC gloves were selected for the second set of experiments. The evaluation of the persistence of gasoline on hands was then carried out using two initial quantities (500 and 1000 microl). Collection was made with PVC gloves after 0, 30 min, 1, 2 and 4h, on different volunteers. The results show a common tendency of massive evaporation of gasoline during the first 30 min: a continued but non-linear decrease was observed along different time intervals. The results of this preliminary study are in agreement with other previous researches conducted on the detection of flammable liquid residues on clothes, shoes and skin.     

Effect of evaporation and matrix interferences on the association of simulated ignitable liquid residues to the corresponding liquid standard

Identification of an ignitable liquid in fire debris evidence can be complicated due to evaporation of the liquid, matrix interferences, and thermal degradation of both the liquid and the matrix. In this research, liquids extracted from simulated fire debris were compared to the original liquid using multivariate statistical procedures. Neat and evaporated gasoline and kerosene standards were spiked onto nylon carpet, which was subsequently burned. The ignitable liquid residues were extracted using a passive headspace procedure and analyzed by gas chromatography-mass spectrometry. Pearson product moment correlation coefficients, hierarchical cluster analysis, and principal components analysis were used to compare the liquids extracted from the carpet to the corresponding neat liquid. For each procedure, association of the extracts according to liquid type was possible, albeit not necessarily to the specific evaporation level. Of the three procedures investigated, principal components analysis offered the most promise since contributions from matrix interferences were essentially eliminated.     

Use of a solid absorbent and an accelerant detection canine for the detection of ignitable liquids burned in a structure fire

ABSTRACT: Ignitable Liquid Absorbent^™ (ILA), a commercial solid absorbent intended to assist fire scene investigators in sample location and collection, has been field tested in three separate room fires. The ability of the ILA to detect and absorb different amounts of gasoline, odorless paint thinner, and camp fuel on two different substrates after a full-scale burn was assessed against results from an accelerant detection canine and laboratory analysis using gas chromatography-mass spectrometry (GC-MS). The canine correctly alerted on most of the panels that contained an ignitable liquid after the fire, while the ILA indicator dye failed to indicate in the presence of gasoline and camp fuel. GC-MS results for ignitable liquid residue from each panel and from the ILA showed that ILA absorbed odorless paint thinner and camp fuel from most of the test panels, but failed to absorb gasoline from the panels on which gasoline was confirmed to be present.     

Breaking point? An analysis of fatal stab wounds to the torso in Ireland between 2011 and 2018, examining the extent of rib fractures

This study examines the pattern of rib injuries occurring in cases of fatal torso stab wounds in Ireland between 2011 and 2018. It has been suggested by previous studies that rib fractures are not commonly sustained in stab wounds to the torso. We wanted to ascertain whether this was the case, as our data suggested that rib fractures were frequent, and where a rib is fractured there is a higher chance of organ injury and death, making this an important area of study. One hundred and forty seven cases of fatal stab wounds from an eight-year period were retrospectively reviewed. Fatal stab wounds to other body areas, were excluded; leaving a total of 104 cases with stab wounds to the torso. We found that 69.2% of cases had rib injuries, a figure significantly higher than previously reported. Our data suggests that stab wounds to the torso often fracture ribs, putting the underlying organs at increased risk of injury and perhaps contributing to fatality. The amount of force needed to cause a rib fracture can be difficult to quantify and indeed from the high percentage of rib fractures sustained in our data it appears that the ribs may be fractured regardless of the amount of force used; this is borne out by the finding that self-inflicted injuries also caused rib fractures. Our study shows that other factors, such as anatomical positioning and wound depth may have a greater bearing than force in terms of whether a rib fracture is sustained.     

A brush fire forensic case.

In Italy, every summer forest fires attract public attention due to the number of victims, the intensity of the fires, the areas devastated, the environmental damage and the loss of property. Excluding some fires by natural causes, other causes are related to the social, economic, and productive profile of the territory. The erroneous expectation is that wooded areas destroyed by fire can then be used for private interests. Often, a fire, started to clear a small area, can completely change the expected result, producing disaster, loss of property, destruction of entire forests and resident fauna, and kill innocent people. In this case report, the reconstruction of an arson scene, the analytical techniques and the results obtained are illustrated in this paper, with the aim of sharing with other research laboratories the current knowledge on forest fire.     

Extent of burn lesions--an analysis of 68 burned cadavers]

The burned bodies (n = 68) autopsied at the Freiburg Institute of Forensic Medicine in the years 1996-2001 (until the end of February) were examined with regard to the extent of consumption by the fire using the classifications suggested by Eckert et al., Maxeiner, Glassman and Crow, and Gerling et al. Further classification parameters were exposure of the body cavities and amputation of extremities as a result of the fire. Most cases were accidental deaths (approximately 75%). The fires occurred mainly in buildings (57%) or vehicles (34%); in 6 cases the burning took place in the open air. In most cases the degree of consumption by the fire was slight to moderate. Only 15% of the burned bodies showed extensive destruction with severe loss of soft tissue and shrinking or amputation of the extremities. In one case the soft tissue was completely destroyed with fragmentation of the calcined skeletal remains. In bodies recovered from house fired the extent of consumption by the fire was usually less pronounced than in bodies retrieved from burned-out vehicles.     

A study of the effects of a Micelle Encapsulator Fire Suppression Agent on dynamic headspace analysis of fire debris samples

The effects of a Micelle Encapsulator Fire Suppression Agent (F-500, Hazard Control Technologies Inc., Fayetteville, Georgia) on the routine analysis of fire debris samples by Gas Chromatography (GC) were studied. When mixed with water the product can be used in the suppression of Class A and Class B fires. Laboratory tests were performed to determine whether or not the product has any effect on the analysis for ignitable liquids by GC, in particular for gasoline, medium petroleum distillates. and heavy petroleum distillates. Test burns were suppressed using either the micelle encapsulator or water and samples collected from these burns were analyzed. The results of analysis show that use of the micelle encapsulator at a fire scene may affect the chromatographic data obtained from samples collected by the investigator. However, the effect does not prevent the identification of common ignitable liquids in fire debris samples.     

Determining the Method Threshold of Identification via Gas Chromatography–Mass Spectrometry of Weathered Gasoline Extracted from Burnt Nylon Carpet,

The Organization of Scientific Area Committees defines threshold of identification as the minimum concentration of ignitable liquid identifiable from gas chromatographic‐mass spectrometry data using accepted pattern identification criteria. We propose a method for determining this threshold for gasoline based on base peak to qualifier ratios of six compounds. The ion ratios were established for each compound in the neat gasoline. These ratios were then compared to those obtained for gasoline and 98% weathered gasoline both spiked onto burnt nylon carpet at 20 ppt down 0.50 ppt, and recovered from the carpet using headspace extraction (ASTM 1412). Identification was confirmed if the compounds’ ion ratios fell within ±25% of that in the neat sample. We found that ion ratios for all samples were acceptable for six compounds at 1.60 and 0.80 ppt for extracted neat and extracted 98% weathered gasoline, respectively, illustrating potential for incorporating into Quality Assurance Programs.     

Evaluation of Cross‐contamination of Nylon Bags with Heavy‐loaded Gasoline Fire Debris and with Automotive Paint Thinner

Nylon bags are used for packaging fire debris in several countries, particularly in Europe. The possibility of cross‐contamination during transport from the fire scene to the laboratory, in normal casework conditions in the U.K., was studied for two brands of nylon bags, using simulated heavy‐loaded fire debris. Three experiments were carried out with each brand, using as sample a piece of cotton fabric soaked with gasoline. One experiment was carried out using automotive paint thinner (oxygenated solvent). Each sample was sealed in a nylon bag and stored in contact with eight empty bags. The empty bags were analysed at regular intervals for a period of time up to 8 weeks, using SPME and GC/MS. Cross‐contamination was found for components of gasoline (toluene and C₂‐alkylbenzenes) in the two brands of nylon bags used, after 4 days and 2 weeks. Cross‐contamination using automotive topcoat thinner was detected after 2 days.     

An apparently jawless cadaver: a case of post-mortem slippage

Passer-by witnesses reported a human cadaver in woodland associated with an agricultural college to police in Northern Ireland. The cadaver comprised reasonably preserved feet, legs and pelvis, with poorly preserved arms and torso, lying with the torso down-slope abutting a fallen tree. A search of the area around the torso, and for some 20m around, failed to find the cranium and mandible. The mandible was found, embedded inside the chest cavity. The cranium was found some 30m away. The victim was later identified as a 24-year old drug addict who had absconded from a local hospital. Mapping of the area led us to speculate that he had tripped and fallen down-slope: other reasons for the body location were also considered. After death, the cadaver had further slipped down-slope forcing the mandible into the chest cavity: slippage of human remains is well-known in forensic and archaeological literature but not well documented. Knowledge of this process of cadaver 'slip' may save wasted police resources in future similar environments where the mandible, and possible other nearby bones appear missing yet are inside the body.     

Extraction of alternative fuels from fire debris samples*

Alternative fuels, specifically biodiesel, biodiesel blends, and E85 fuel, have been gaining a market share over the past few years. With the emergence of these fuels, fire debris analysts should be able to recognize their characteristics since these fuels may be encountered in casework. In this study, pure biodiesel (B100) and a 20% blend of pure biodiesel with petroleum diesel (B20) are examined as liquids and are extracted from debris samples using both passive headspace concentration and solvent extraction. Typical fire debris instrumental conditions are used to analyze these samples. Components of B100 and B20 may be observed in debris samples extracted using the passive headspace concentration method, but the chromatographic patterns are different from the pure liquid samples. When solvent extraction is used as a secondary extraction method on debris samples, the resulting patterns are consistent with the pure liquids of B100 and B20. E85 fuel, a blend of 85% ethanol and 15% gasoline, can be extracted using a typical fire debris extraction technique but requires slight modifications to typical fire debris instrumental conditions. E85 is shown at various stages of evaporation to demonstrate the resiliency of the ethanol. Additionally, samples of E85 were placed on carpet, burned and extinguished to demonstrate the effects of the suppression medium on the retention of ethanol.     

建立火场样品中汽油残留物ATD-GC-MS检验结果的评价方法

目的建立火场中汽油燃烧残留物ATD-GC-MS检验结果评价方法。方法将模拟燃烧样品用ATD-GC-MS法检验,检验结果通过对芳烃、烷烃、茚满、和萘系列的4个特征离子色谱图与已知汽油作比较,并利用向量夹角法计算样品与汽油色谱指纹图的相似度来对检验结果作评价。结果有汽油作助燃剂的模拟燃烧样品与汽油色谱指纹图的相似度一般大于90%,无汽油作助燃剂的样品则在60%以下。结论利用样品的4个特征离子色谱图与已知汽油作比较,并结合样品与汽油色谱指纹图相似度的计算,能对检验结果作出客观、可靠和准确的评价。     

Factors influencing the precision of estimating the postmortem interval using the triple-exponential formulae (TEF). Part I. A study of the effect of body variables and covering of the torso on the postmortem brain, liver and rectal cooling rates in 117 forensic cases

Brain, liver, rectal and environmental temperatures were continuously monitored under controlled conditions, in 117 forensic fatalities, for up to 60 h after death. Cases were studied either naked (63%) or covered with two blankets (37%). Bodies were classified into fat and thin groups. Statistical analysis and curve-fitting of the data yielded the average triple-exponential formulae for each body site and each body group. The effects of covering of the torso and body parameters such as weight, height, surface area and 'cooling size factor' (Z) on postmortem cooling are assessed and discussed. Results show that covering of the torso has a significant influence on the rate of postmortem cooling, however, there is no good correlation between the body variables and the cooling rate.     

Adsorption saturation and chromatographic distortion effects on passive headspace sampling with activated charcoal in fire debris analysis

Distortion of the chromatographic profile obtained for hydrocarbons that have been sampled by adsorption onto activated charcoal is a well-known phenomenon. The work reported here helps to better define the causes of chromatographic profile distortion and offers a potential method to avoid chromatographic distortion in some cases through a subsampling technique. The recovery of hydrocarbons from an equimolar mixture was investigated to determine the influence of hydrocarbon concentration on the molar ratios of recovered components. In a one-quart container, hydrocarbon volumes as small as 24 microL (liquid) were sufficient to saturate the surface area available for adsorption on a 99.0 mm2 square of activated charcoal, resulting in significant distortions in the molar ratio and the chromatographic profile of the recovered hydrocarbons. Passive headspace sampling of a similarly small volume of unweathered gasoline spiked onto carpet padding resulted in a significant distortion of the chromatographic profile. The chromatographic profile of the recovered hydrocarbons closely resembled 75% weathered gasoline. Heating the container spiked with unweathered gasoline to evenly distribute the components and then removing a subsample of the carpet padding to a second container for passive headspace analysis greatly reduced the amount of distortion in the resulting chromatogram.     

火场样品中汽油与稀释剂燃烧残留物的区分方法探讨

目的探讨火场样品中汽油与稀释剂燃烧残留物的区分方法。方法样品用ATD—GC—MS法检验,检验结果通过对芳烃、烷烃、茚满、和萘系列的4个特征离子色谱图与已知汽油和稀释剂作比较,并结合向量夹角法计算样品与汽油色谱指纹图的相似度来区分汽油与稀释剂残留物。结果个别品种的稀释剂燃烧残留物与汽油很相似,但彼此有某些差别。结论使用本方法,一般能将汽油与稀释剂燃烧残留物区分开。     

The forensic medical expertise of the victims of large-scale fires]

The difficulties of present-day forensic medical expert evaluation of poisonings in fires are explained by exposure of man to highly toxic compounds that form during burning of polymers. Analyzing forensic medical expert evaluations of a large number of victims dead in a large-scale fire, the authors emphasize the necessity of measuring not only dead people's blood levels of HbCO, but of some other toxic combustion products that may exert combined effects on human body. The authors think it desirable that criteria of forensic medical evaluation of combined poisoning in fire be defined.     

Association of Ignitable Liquid Residues to Neat Ignitable Liquids in the Presence of Matrix Interferences Using Chemometric Procedures*,†

Abstract: In fire debris analysis, weathering of ignitable liquids and matrix interferences can make the identification of ignitable liquid residues (ILRs) difficult. An objective method was developed to associate ILRs with the corresponding neat liquid with discrimination from matrix interferences using principal components analysis (PCA) and Pearson product moment correlation (PPMC) coefficients. Six ignitable liquids (gasoline, diesel, ultra pure paraffin lamp oil, adhesive remover, torch fuel, paint thinner) were spiked onto carpet, which was burned, then extracted using passive headspace extraction, and analyzed by gas chromatography‐mass spectrometry. Both light and heavy burn conditions were investigated. In the PCA scores plot, ignitable liquids were discriminated based on alkane and aromatic content. All ILRs were successfully associated with the corresponding neat liquid using both PCA and PPMC coefficients, regardless of the extent of burning. The method developed in this research may make the association of ILRs with corresponding neat liquids more objective.     

Using Alkylate Components for Classifying Gasoline in Fire Debris Samples

The characteristic that discriminates gasoline from other ignitable liquids is that it contains high‐octane blending components. This study elaborates on the idea that the presence of gasoline in fire debris samples should be based on the detection of known high‐octane blending components. The potential of the high‐octane blending component alkylate as a characteristic feature for gasoline detection and identification in fire debris samples is explored. We have devised characteristic features for the detection of alkylate and verified the presence of alkylate in a large collection of gasoline samples from petrol stations in the Netherlands. Alkylate was detected in the vast majority of the samples. It is demonstrated that alkylate can be detected in fire debris samples that contain traces of gasoline by means of routine GC‐MS methods. Detection of alkylate, alongside other gasoline blend components, results in a more solid foundation for gasoline detection and identification in fire debris samples.