Toxicological investigation of liquid petroleum gas explosion: human model for propane/ethyl mercaptan exposures

Four individuals died as the result of a propane explosion. As with many propane explosions, the question was raised as to the adequacy of the product's odorization after the autopsy studies had been conducted. In most cases, this question leads to litigation. Ethyl mercaptan is a widely used odorant for propane and was used in this instance. Three of the four victims had blood available at autopsy for study. Quantitative analyses of the victims' blood, obtained during autopsy, were performed using gas chromatography/mass spectrometry, without subjecting the samples to hydrolysis. These analyses determined the relative amounts of propane and ethyl mercaptan in the blood to be 90, 63, and 175 mL/m3 headspace, and 0.36, 0.34, and 0.77 microgram/L blood, respectively. Since mercaptans have been reported in human blood as products of metabolism, modeling studies were conducted to establish the validity of the autopsy data and to develop an autopsy toxicology protocol for investigating explosion deaths. When subjects were not exposed to an atmosphere containing ethyl mercaptan, dimethylsulfide was the only mercaptan detectable in their blood without severe hydrolysis prior to analysis. Metabolic ethyl mercaptan is sufficiently bound to be undetectable by the methods used without hydrolysis. Human subjects were exposed to a flammable mixture of air and propane odorized with ethyl mercaptan. The analyses of the blood from these subjects produced results which were comparable with those for the explosion victims, establishing that the question of odorant adequacy can be addressed at the autopsy of propane explosion victims. It is extremely important that the pathologist and toxicologist investigating gas explosion deaths recognize the valuable evidence existing in the victim's blood.     

Suicide by explosion of natural gas: case report and review of literature

Natural gas (NG) is used as a home energy supply and, with or without ignition, is rarely misused to result in death. The authors report an unusual suicidal explosive death induced by NG. A huge explosion with resultant fire had blown out a bungalow, with destructive damage predominantly above the ground, resulting in only 1 exterior wall and the foundation still in place. The victim was transferred to the hospital, and on the way, he admitted to undoing the natural gas fitting and to igniting the source. He survived for a short interval of time in the hospital before all resuscitative efforts failed. During autopsy, a special attention was paid to victim's identification and search for other injuries, not related to the explosion, so as to exclude or document homicidal injuries disguised by the subsequent explosion. The forensic pathologist should be aware of the different kinds of inflammable substances and integrate the findings with the scene information and the impression of the investigators at the scene.     

顶空气相色谱法检测生物检材中乙醇及其相关物质

目的建立生物检材中乙醇及其相关物质的检测方法。方法生物检材加入内标异丙醇后用顶空气相色谱法进行检测（FID检测器）,以保留时间定性,内标法定量。结果该方法线性范围为0．05035-1．613mg／ml。相关系数r=0．9999,最低检测限（limit of detection,LOD）3．379μg／ml,分析方法平均回收率为98．24％～106．5％,日内精密度RSD〈2．2％,日间精密度RSD〈1．4％,总分析时间不超过18min。结论该方法可用于生物检材中乙醇及其相关物质的检测。     

Case involving differentiation of deer and human bone fragments

In a recent Louisiana forensic anthropology case, it was necessary to attempt species identification of six small bone fragments. The primary concern was whether or not they matched the fractured humerus of a woman killed by two shotgun blasts and then disposed of in the Mississippi River. These tiny fragments were recovered by law enforcement officers inside a jeep pickup and at the gas station where the vehicle had been cleaned. The police suspect claimed that these fragments were from a deer that he had recently killed. The small size of the pieces precluded positive recognition of human versus nonhuman origin based upon gross morphology and cortical thickness. Microscopic examination was possible. This analysis involved comparison of the unknown specimens to reference deer and human thin sections including bone recovered from the woman during autopsy. Examination of the jeep and gas station fragments revealed no plexiform bone, secondary (not primary) osteons, and variability in size and shape of the osteons and Haversian canals. These and other variables identified the bone fragments as human.     

Explosion Scene Forensic Image Interpretation

Image interpretation is an important aspect in the field of forensic science; however, it is seldom reported how to use these techniques in explosion scene forensic investigations. On 12 August 2015, a series of explosions killed 165 people and injured hundreds more at a container storage station at the Port of Tianjin. In this study, we applied image interpretation methods to determine the seat of the explosion by analyzing low‐quality video clips of the event. The interpretation fits well with recently published standard operating procedures, including the hypothesis, evaluation, inference, and confirmation. Image processing was adopted to enhance the images while the explosion scene was reconstructed with the same images. Some important features were extracted and utilized to distinguish whether the flashes were caused by reflection or a real blast. We reveal the real explosion location, which guides the overall investigation. The results indicate that image interpretation is a powerful tool for forensic investigators to analyze low‐quality images in complicated explosions or fire accidents.     

The gas chromatographic detection of acetylene in cadaveric material]

Acetylene traces were detected by gas chromatography in the cadaveric right crural muscle of a 30-year-old man dead from an explosion of an acetylene reservoir at a plant. Acetylene was identified using the absolute calibration method on 3 standard gas chromatographic columns, reaction gas chromatography, and acetylene "deduction" by silver sulfate on silicagel.     

Toxicologic findings in the USS Iowa disaster.

The toxicologic results from the 47 victims of the explosion on the USS Iowa are presented. Good correlation between carboxyhemoglobin saturations and cause of death was found. There were no correlations between blood cyanide concentrations and causes of death. Volatile analysis suggested postmortem ethanol production rather than antemortem ethanol ingestion. No drugs except nicotine were detected in any of the victims.     

Deaths Due to Accidental Air Conditioner Compressor Explosion: A Case Series

In an air‐conditioning system, the compressor is a large electric pump that pressurizes the refrigerant gas as part of the process of turning it back into a liquid. The explosion of an air conditioner (AC) compressor is an uncommon event, and immediate death resulted from the blast effect is not reported in forensic literature. We report three such cases in which young AC mechanics were killed on the spot due to compressor blast, while repairing the domestic split AC unit. The autopsy findings, the circumstances leading to the explosion of the compressor, are discussed in this study.     

Serum alcohol concentrations in trauma patients determined by immunoassay versus gas chromatography

There has been an extensive discussion in the forensic toxicology community regarding the effect of trauma on the enzymatic method for ethanol analysis. There is a paucity of information in the literature that addresses this question. This study was designed to compare the Dade Behring Dimension enzymatic method with the reliable gas chromatographic method. The blood samples collected at the same time from trauma patients were analyzed by both methods. The result of the study shows no significant quantitative difference between the enzymatic and gas liquid chromatographic (GLC) methods. Also, the enzymatic method did not show any false positive ethanol in cases where the GLC method showed a negative finding.     

Dynamic pressure measurement of cartridge operated vole captive bolt devices

IntroductionVole captive bolt devices are powder actuated spring guns that are used as a pest control mean. After having triggered the explosion of the blank cartridge by touching a metal ring around the muzzle, the vole is killed by the massive propulsion of the gas jet. Improper use and recklessness while handling these devices may cause severe injuries with the hand of the operator at particular risk. Currently, there are no experimental investigations on the ballistic background of these devices.MethodsAn experimental test set-up was designed for measurement of the firing pressure and the dynamic force of the gas jet of a vole captive bolt device. Therefore, a vole captive bolt device was prepared with a pressure take-off channel and a piezoelectric transducer for measurement of the firing pressure. For measurement of the dynamic impact force of the gas jet an annular quartz force sensor was installed on a test bench. Each three simultaneous measurements of the cartridges’ firing pressure and the dynamic force of the blast wave were taken at various distances between muzzle and load washer.ResultsThe maximum gas pressure in the explosion chamber was up to 1100 bar. The shot development over time showed a typical gas pressure curve. Flow velocity of the gas jet was up to 2000 m/s. The maximum impact force of the gas jet at the target showed a strong inverse ratio to the muzzle's distance and was up to 11,500 N for the contact shot distance. Energy density of the gas jet for the close contact shot was far beyond the energy density required for skin penetration.ConclusionThe unique design features (short tube between cartridge mouth and muzzle and narrow diameter of the muzzle) of these gadgets are responsible for the high firing pressure, velocity and force of the gas jet. These findings explain the trauma mechanics of the extensive tissue damage observed in accidental shots of these devices.     

Frozen human bone: a microscopic investigation

The taphonomic effects of prolonged extreme cold and freezing on human bone have received little research attention. Questions of specific interest include whether previously frozen bone can be identified and whether freezing alters the structural integrity enough to prevent histological aging. There is no evidence from previous studies that freezing damages the structural integrity, and to date no research investigating the freezing process on bone microstructure has been undertaken. This research attempts to distinguish histologically previously frozen bone from nonfrozen bone by identifying patterned defects. To determine the effects of freezing in bone microstructure using light and scanning electron microscopy (SEM), several human bone sections were subjected to prolonged freezing and allowed to thaw before thin sectioning. Light microscopy failed to demonstrate statistically significant differences between frozen and nonfrozen specimens. SEM analysis revealed fractures, although these lacked pattern and did not occur systematically throughout the section. Evidence of microstructural changes caused by liquid expansion, however, was remarkable but did not alter the structural integrity of the microstructure. The results of this study suggest that freezing does not alter the process of histomorphological analysis.     

Effects of kinetic energy and firearm-to-target distance on fracture behavior in flat bones

This research implements a fractographic approach to investigate the relationships between kinetic energy, firearm-to-target distance, and various aspects of fracture behavior in gunshot trauma. Gunshot experiments were performed on pig scapulae (n = 30) using three firearms generating different muzzle (initial) kinetic energies, including a 0.32 pistol (103 J), 0.40 pistol (492 J), and 0.308 rifle (2275 J). Specimens were shot from two distances: 10 cm (n = 15) and 110 cm (n = 15). Features evaluated in fractographic analysis such as cone cracks, radiating cracks, crack branching points, and circumferential cracks could be easily identified and measured in flat bones and allowed for statistical comparison of crack propagation behavior under different impact conditions. Higher-energy bullets produced more radiating cracks, more crack branching points, and longer fracture lengths than lower-energy bullets. Distance had no significant effect on fracture morphology at the distances tested. That quantitative measures of crack propagation varied with energy affirms that kinetic energy transfer is important in determining the nature and extent of fracture in gunshot wounds and suggests it may be possible to infer relatively high- versus relatively low-energy transfer using these features. Ranges obtained with the three firearms exhibited considerable overlap, however, indicating that other variables such as bullet caliber, mass, and construction influence the efficiency of energy transfer from bullet to bone. Therefore, fracture morphology cannot be used to identify a specific firearm or to directly reconstruct the muzzle (initial) kinetic energy in forensic cases.     

Unusual wound morphology after textile penetration by the automatic rifle (StG) 58. A case report

Technical characteristics of the used fire-arm and ammunition, the firing range and the shot through garments of the victim are essential factors, that exercise an influence on the appearance of gunshot injuries. An exemplary case-report shall emphasize the importance of these factors. It deals with a suicidal double-shot fired from an automatic rifle by a young soldier. The wounds were localized in the left chest region and the adjacent skin was blackened by soot in a remarkable geometrical pattern, although an ammunition with a smokeless charge has been used. By means of comparative shots we have good reasons to suppose this phenomenon to be caused by rests of gun powder and pressure of the explosion gas leaved in the barrel after the first shot. The second projectile pushed out this explosion gas to the skin that had been uncovered in a star-shaped way by the first shot.     

Forensic applications of stable isotope analysis: Case studies of the origins of water in mislabeled beer and contaminated diesel fuel

This paper describes the use of oxygen (¹⁸O) isotope analysis of water contained in two different materials — beer and diesel fuel — involved in the resolution of two separate cases. In the first case study, it was possible to demonstrate that a sample of beer labelled as premium brand in fact belonged to a cheap brand. The second case related to the contamination of diesel fuel from a service station. The diesel fuel contained visible amounts of water, which caused vehicles that had been filled up with it to become defective. For insurance purposes, it was necessary to determine the source of water. The δ¹⁸O values for the water of nearly all samples of diesel was close to the δ¹⁸O of local tap water at the filling station.     

论公共场所爆炸现场的快速处置与勘验

火车站等公共场所发生爆炸后,警方要采取应急警务对犯罪嫌疑人、受伤亡人员、现场秩序、痕迹物证保全与记录等开展快速处置与勘验。爆炸现场快速处置与勘验就是现场整体清理与转移,虽然现场的原始位置变化了,但是载体及其位置关系还在,特别是整体搬迁的残留物、抛出物等相互关系也要记录好。现场编号是勘查人员对现场的场所区域、痕迹物证分布、尸体位置等所做的标记,这种外在的符号添加和记录留存应该与现场客观记录的需要相匹配。     

The effects of chemical and heat maceration techniques on the recovery of nuclear and mitochondrial DNA from bone

Forensic anthropologists use a number of maceration techniques to facilitate skeletal analysis of personal identity and trauma, but they may unwittingly eliminate valuable DNA evidence in the process. This study evaluated the effect of 10 maceration methods on gross bone structure and the preservation of DNA in ribs of 12 pigs (Sus scrofa). A scoring system was applied to evaluate the ease of maceration and resulting bone quality while DNA purity was quantified by optical densitometry analysis, followed by polymerase chain reaction (PCR) amplification of three mitochondrial and three nuclear loci. The results demonstrated that while mitochondrial DNA could be amplified for all experiments, cleaning treatments using bleach, hydrogen peroxide, ethylenediaminetetraacetic acid/papain, room temperature water and detergent/sodium carbonate followed by degreasing had low DNA concentrations and failed to generate nuclear PCR products. In general, treatments performed at high temperatures (90 degrees C or above) for short durations performed best. This study shows that traditionally "conservative" maceration techniques are not necessarily the best methods to yield DNA from skeletal tissue.     

法律漏洞类型化及其补充——以物权相邻关系为例

基于发现法律漏洞和填补法律漏洞的不同方式,应把法律漏洞分为禁止拒绝裁判式漏洞、目的漏洞和原则漏洞三种大类。在具体操作层面,基于应然判断的逻辑形式,类推在逻辑上并非基于案件的实质相似性,而是一个先抽象反思(归纳)再演绎的过程;目的性扩张为类推的一种特殊类型;总体类推应属于目的漏洞而非原则漏洞。在漏洞确认和漏洞填补两者的关系上,目的漏洞和原则漏洞没有本质不同,即在这两者漏洞确认和漏洞填补都并非是一个完全同一的过程。运用民法不动产相邻关系中的具体例子,来具体说明法律漏洞补充的理论,从而也对物权法不动产相邻关系相关规范的具体解释适用提出了一些新的见解。     

Acute flurazepam intoxication: a case report

A fatality due to ingestion of flurazepam is reported. Flurazepam is a benzodiazepine, a widely prescribed hypnotic drug for use in sleep disorders. There are only few documented reports of the disposition of flurazepam in deaths due to overdose. A 68-year-old woman was found deceased at home with no evidence of trauma or asphyxia. Toxicologic analyses were performed and drug levels measured by means of gas chromatography coupled to mass spectrometry. The flurazepam concentration in each specimen was as follows: heart blood 2.8 microg/mL, bile 323 microg/mL, and urine 172 microg/mL. Presence of flurazepam into gastric content was observed too. Based on the autopsy findings, patient history, and toxicologic results, the cause of death was determined to be acute intoxication of flurazepam and the manner, suicide.     

The influence of footwear sole hardness on slip initiation in young adults

Slips occur when the friction demand of an individual exceeds the friction available from the shoe/floor interface. Shoe sole hardness is one of the factors thought to influence friction demand and available friction. The purpose of this study was to determine the influence of footwear sole hardness on the probability of slip initiation. Forty young adults were randomized into a hard or soft sole group. Slip events during the slippery floor trials were documented using a motion analysis system. The proportion of slip events in the hard sole group was greater than that in the soft sole group. The difference between utilized and available friction accurately predicted 90% of slip outcomes. Our data support the premise that individuals wearing shoes with harder soles are at greater risk for slipping. The results of this study suggest that shoe sole hardness should be considered when designing footwear aimed at decreasing slip risk.     

Analysis of hydrogen cyanide in air in a case of attempted cyanide poisoning

A 32-year-old man attempted to poison his ex-girlfriend with hydrogen cyanide by hiding the pesticide Uragan D2 in her car. During the police investigation, chemical analysis of the air inside the car was performed. Hydrogen cyanide was detected through on-site air analysis using a portable Fourier transform infrared (FTIR) spectroscopy gas analyzer and colorimetric gas detection tubes. Furthermore, impinger air-sampling was performed for off-site sample preparation and analysis by gas chromatography-mass spectrometry (GC-MS). All three independent techniques demonstrated the presence of hydrogen cyanide, at concentrations of 14-20ppm. Owing to the high volatility of hydrogen cyanide, the temperature and the time since exposure have a substantial effect on the likelihood of detecting hydrogen cyanide at a crime scene. The prevailing conditions (closed space, low temperature) must have supported the preservation of HCN in the car thus enabling the identification even though the analysis was performed several days after the hydrogen cyanide source was removed. This paper demonstrates the applicability of combining on-site FTIR measurements and off-site GC-MS analysis of a crime scene in order to ensure fast detection as well as unambiguous identification for forensic purposes of hydrogen cyanide in air.