Suicidal asphyxiation by inhalation of automobile emission without carbon monoxide poisoning

Reported herein is the suicidal asphyxiation of a young man due to exhaustion of oxygen in the interior of a sealed automobile into which the exhaust emissions were diverted. His blood carboxyhemaglobin concentration was less than 5% saturation. The car was equipped with a catalytic converter and when tested, the exhaust carbon monoxide concentration was 0.01%.     

Deaths caused by carbon monoxide poisoning in an open environment (outdoors)

Three deaths as a result of inhalation of carbon monoxide from the exhaust fumes of automobiles are reported. All deaths occurred outside and not in a structure. The individuals were white males, ages 24 to 26 years. Blood carboxyhemoglobin concentrations ranged from 58 (in a decomposing body) to 81%. The three cases illustrate the fact that even in the outdoors death from carbon monoxide inhalation can occur if an individual is in close proximity to a rich source of carbon monoxide.     

Fetal death due to nonlethal maternal carbon monoxide poisoning

Fetal death due to acute carbon monoxide poisoning is rarely reported in the medical literature. Of the eight cases found in literature review, only one documented the fetal carboxyhemoglobin concentration. This paper reports a fetal death due to accidental nonlethal maternal carbon monoxide intoxication in which both maternal and fetal carboxyhemoglobin concentrations were obtained. The corrected carboxyhemoglobin concentration was 61% at the time of death in utero, while the maternal carboxyhemoglobin was measured at 7% after one hour of supplemental oxygen. The authors review the mechanisms of fetal death and emphasize the different carbon monoxide kinetics in the fetal circulation.     

Alcohol stove as a source of CO poisoning in a camper

Although the number of deaths from fatal CO poisoning has strongly declined since the change from coal gas to natural gas, accidental and suicidal carbon monoxide intoxications still have to be expected. In motor vehicles the exhaust gases from the engine and a stationary heating are the major sources of intoxication. In closed campers and caravans the operation of gas and spirit cooking stoves etc. may also lead to an accumulation of carbon monoxide due to incomplete combustion.     

Diesel fumes do kill: a case of fatal carbon monoxide poisoning directly attributed to diesel fuel exhaust with a 10-year retrospective case and literature review*

While it is known that diesel fuel combustion engines produce much lower concentrations of carbon monoxide (CO) than gasoline engines, these emissions could certainly generate lethal ambient concentrations given a sufficient amount of time in an enclosed space and under suitable environmental conditions. The authors report a case of CO poisoning which was initially referred for autopsy as a presumed natural death of a truck driver found in the secure cab of a running diesel tractor trailer truck. Completion of the preliminary investigation ascribed death to complications of ischemic heart disease (IHD), pending toxicological analysis that included quantification of CO. When the toxicology results showed lethal blood COHbg, the cause of death was re-certified as CO intoxication secondary to inhalation of (diesel) vehicular exhaust fumes. Because of the unique source of fatal CO intoxication in this case, the contributory IHD and the possible contaminants in the putrefied blood, a 10-year retrospective review was conducted on all nonfire related CO deaths autopsied (n = 94) at the Office of the Chief Medical Examiner in Louisville, KY from 1994 to 2003. For validation of the COHbg detection method used by the Kentucky Office of Forensic Toxicology (KYOFT), blood samples from these cases along with controls were submitted to three laboratories using various analytical methods yielding no statistically significant differences. Lastly, an extensive literature review produced no scientifically reported cases of fatal CO poisoning attributed to diesel fuel exhaust.     

Suicidal carbon monoxide poisoning in an automobile with the engine switched off

Report is made on a suicidal carbon monoxide poisoning through entrance of exhaust fumes into the interior of the vehicle. The situation of discovery (switched-off engine) occasioned experimental examinations. The result showed that fatal carbon monoxide concentrations can obviously remain in the interior of a vehicle over a long period of time.     

Experimental studies on death by fire in automobiles and exhaust gas poisoning

Studies were made on the acid-base balance, blood gases, and carbon monoxide (CO), cyanide, and sulfur dioxide concentrations in the blood of albino rabbits that died from automobile exhaust gas poisoning (group I) or fires in cars (complete combustion, group II; incomplete combustion, group III). In group I, the temperature and CO concentration increased gradually to 35 degrees C and 5.2% in 70 min. The animals died after 9 min, when the values were 20 degrees C and 5.2%, respectively. In group II the animals died after 9 min, when the values were 55 degrees C and 1.95%, respectively. In group III, the temperature was very high (870 degrees C), but the CO concentration was not (0.6-1.3%) after 4 min. The animals died after 5 min. In all experimental groups, marked acidosis and hypoxemia were seen, but the CO2 tension (PCO2) was high, in contrast to previous studies on pure CO poisoning. In group I, the level of carboxyhemoglobin (CO-Hb) was significantly higher (91.2 +/- 3.4% in arterial blood, 87.5 +/- 8.1% in venous blood; p less than 0.01) than in groups II and III. Although the O2 tensions of venous and arterial blood (PvO2, PaO2) were very low, that of arterial blood was higher, suggesting that O2 was still being utilized in the tissues at the time of death. In group II, CO-Hb was high (57.7 +/- 16.0% in arterial blood, 61.2 +/- 20.6% in venous blood) and the acid-base balance indicated marked acidosis. In group III, the CO-Hb, PCO2 and cyanide levels in the blood were very high.(ABSTRACT TRUNCATED AT 250 WORDS)     

Negligent homicide caused by exhaust gas escaping from a manipulated chimney

A chimney built and operated according to the instructions is supposed to ensure that the combustion gases coming from the fireplace can escape safely. If the operational reliability is impaired, this presents a risk of acute poisoning. The report deals with a negligently caused carbon monoxide poisoning of a married couple as a consequence of improper installation of a cover of the chimney opening. Various causes of fatal poisoning due to defective exhaust systems are discussed in connection with the presented case report.     

Death scene evaluation in a case of fatal accidental carbon monoxide toxicity

Exposure of humans to high concentrations of carbon monoxide can result in death, due to the formation of carboxyhaemoglobin (COHb), which impairs the oxygen carrying capacity of the haemoglobin. Carbon monoxide is responsible of a great number of accidental domestic poisonings and deaths throughout the world, particularly in homes that have faulty or poorly vented combustion appliances. A case is reported, in which a 21-year-old woman was found dead, due to carbon monoxide poisoning from a gas water heater, despite the puzzling evidence that the heater has been used for more than 10 years without any problem. An evaluation of the exposure to CO was performed, by measuiring the rate of production of CO from the heater, and using the Coburn-Forster-Kane equation to describe the kinetics of the poisoning process. The death was attributed to an accidental poisoning from carbon monoxide due to a sum of unfortunate circumstances.     

Suicidal carbon monoxide inhalation of exhaust fumes. Investigation of cases

The inhalation of automobile exhaust gases is a relatively frequent suicidal method. Two such cases of special interest to forensic pathology and toxicology have been introduced. In case 1, a suicide note disclosed the victim's mental state, the inside conditions of the car, and toxic effects of automobile exhaust. In case 2, a reconstruction experiment has revealed important factors for the investigation of the scene, such as the size of a vinyl hose, the conditions of connecting site of the hose with the exhaust pipe, etc.     

The role of hydrogen cyanide and carbon monoxide in fire casualties: a prospective study

Determinations of blood cyanide and carboxyhemoglobin concentrations were performed in 18 victims found dead in buildings after fires during a 2-year period. The results indicated that 50% of the victims had been exposed to toxic levels of hydrogen cyanide and 90% to toxic levels of carbon monoxide. Lethal concentrations of carbon monoxide were found in 83% of the victims. In one case a lethal blood cyanide but a non-toxic blood carboxyhemoglobin value was found. It is concluded that carbon monoxide appears to be more important than hydrogen cyanide as a toxic agent in the fire atmosphere, but cyanide poisoning without carbon monoxide poisoning may, under certain circumstances, be the cause of death in fire victims.     

An unusual case of 3 fatal, accidental CO poisoning cases by re-routed ventilation

A case of fatal carbon monoxide poisoning is presented where three members of a family, aged between 23 and 66 years, died while having dinner. After analysing the scene and evaluating the personal circumstances there was no doubt that death was due to accidental carbon monoxide poisoning. The fact that three persons of different ages died almost simultaneously as well as the technical reconstruction appears noteworthy to the authors. Scrutiny of the technical circumstances revealed that the waste air containing carbon monoxide was re-routed because of the oppressively hot weather conditions. The fumes from the stove heating in the living room flowed into the chimney and from there via another pipe into the kitchen oven and finally reached the atmosphere of the kitchen where the three members of the family died.     

Studies on asphyxia: on the changes of the alveolar walls of rats in the hypoxic state. II. The hypoxic state produced by carbon dioxide and methane gases

Experimental studies were presented here concerning death by asphyxia due to the inhalation of carbon dioxide and methane gases. The morphological changes were almost the same as those demonstrated in our previous report. The authors concluded that the morphological changes in the lung tissue were not attributable to the chemical specificity of gases used in the experiment but to the decrease of oxygen.     

Trigemino‐Cardiac Reflex as Lethal Mechanism in a Suicidal Fire Death Case

In the vast majority of immediate fire deaths, the mechanism of death is inhalation of toxic gases (especially carbon monoxide), direct thermal injury, or neurogenic shock due to the redistribution of the body's blood volume produced by surface heat on the skin. We present a suicidal case that is unusual because the mechanism of immediate fire death could arguably be explained in terms of a primitive autonomic reflex/the trigemino‐cardiac reflex. Although this reflex is well known to surgeons and anesthetists, with possible lethal consequences in the course of invasive surgical procedures on the head and neck region, it is much less familiar to forensic pathologists.     

Significance of hydrocyanic acid formation during fires]

Cyanide concentrations of blood samples from fire victims autopsied in the Institute of Legal Medicine, Munich, have been determined. In 25% of 48 analyzed cases cyanide concentrations from 0.52 microgram to 6.24 microgram Cyanide/ml blood have been detected. These results are compared to former studies and the higher mean level in our collective is emphasized. The importance of hydrocyanid acid in the toxicity of fire gases is evidently greater, than assumed. Hydrocyanic acid may be produced from nitrogen continaing polymers during combustion. The quote of these polymers in clothing, furniture, and also in equipment of cars is increasing. Therefore, it is necessary to take more notice of the formation of hydrocyanic acid during combustion, even though carbon monoxide is in general the main toxic agent in fire gases.     

Fatal carbon monoxide poisoning after the detonation of explosives in an underground mine: a case report.

An unusual death caused by carbon monoxide poisoning after the detonation of explosives in an underground mine was investigated by the Office of the Medical Investigator of the State of New Mexico. The 50-year-old miner had 18 years of mining experience but no documented safety training. He collapsed approximately 20 minutes after entering the mine and working at the bottom of the single vertical shaft. The tight confines of the mine shaft hindered rescue personnel from reaching him, and the body was not recovered until 2 days later. The autopsy showed severe coronary artery atherosclerosis with remote and resolving myocardial microinfarcts, as well as the characteristic pink lividity of carbon monoxide poisoning, which was confirmed by laboratory analysis. Detailed investigation of the scene revealed no sources of carbon monoxide other than the explosives. The case represents an uncommon cause of death in mining that may have been avoided through the use of proper safety procedures, and illustrates the importance of recognizing the many sources of carbon monoxide.     

The application of NIST's Fire Dynamics Simulator to the investigation of carbon monoxide exposure in the deaths of three Pittsburgh fire fighters

A case is reported in which computer fire modeling was used to reevaluate a fire that killed three fire fighters. NIST's Fire Dynamics Simulator (FDS) was employed to model the fire in order to estimate the concentration of carbon monoxide present in the dwelling, which was the immediate cause of death of two of the fire fighters, who appear to have removed their face pieces in order to share available air. This estimate, along with an assumed respiration volume and known blood carboxyhemoglobin, was plugged into a standard equation to estimate the time of exposure. The model indicated that 27 min into the fire, the carbon monoxide concentration had already reached approximately 3600 ppm. At this concentration, and a respiration of 70 L/min, an estimated 3 to 8 min of exposure would have been required to accumulate the concentrations of carboxyhemoglobin (49, 44, and 10%) measured on the fire fighters at autopsy.     

A study on house fire victims: age, carboxyhemoglobin, hydrogen cyanide and hemolysis.

Correlation among age, concentrations of carboxyhemoglobin and hydrogen cyanide, oxygen density and hemolysis were studied in 120 house fire victims. Victims aged over 60 years comprised approximately 50% of the pooled subjects. Blood samples were mainly collected from the left ventricle, but sometimes from both the right and left ventricles. The concentration of carboxyhemoglobin ranged from 1-95%, of which 71 persons (59.7%) died with carboxyhemoglobin concentrations below 60%. Carboxyhemoglobin concentrations below 10% were found in 9 persons (7.5%). Most of these cases involved the elderly persons. In this paper, we report on the death of elderly victims as a result of low carboxyhemoglobin concentrations. A significant correlation of blood carboxyhemoglobin concentrations existed between the right and left ventricles. The concentration of carboxyhemoglobin in the left ventricle was significantly higher than that in the right. Two out of 31 victims whose hydrogen cyanide concentrations were determined, succumbed to hydrogen cyanide poisoning, having a high concentration of hydrogen cyanide and a low concentration of carboxyhemoglobin. On analysis, oxygen density was found to be low in 13 persons. A negative correlation was shown between carboxyhemoglobin concentration and hemolysis. Inasmuch as hemolysis may indicate the extent of heat dissociation, hemolysis should provide an index of carbon monoxide dissociation from carboxyhemoglobin. In the present study of victims, possible causes of death i.e., carbon monoxide gas poisoning, hydrogen cyanide poisoning, oxygen deprivation, burning, shock due to burns and others were estimated. The survival time for elderly victims was considered to be short.     

Fatal poisoning in childhood, England & Wales 1968-2000

We analysed deaths certified as due to poisoning in England & Wales, 1968-2000, in children aged <10 years by age, sex, circumstances of death, intent, and agents involved. The number of deaths fell from 165 (20.6 per million children) in 1968 to 30 (4.6 per million) in 2000, a decrease of approximately 80%. The age-specific death rates were similar in boys and girls. The rate was initially much higher, and fell more, in those aged <5 years. Most deaths (n=1923) occurred in fires, and had been attributed to inhaling combustion products. A small number (n=104) occurred in fires resulting from motor vehicle and other transport accidents. From 1979 (use of ICD-9) the coding of some of these deaths changed from poisoning with carbon monoxide to poisoning with 'other gases, fumes or vapours'. These 'fire deaths' do not appear as poisonings in mortality statistics based on a single underlying cause of death, and cannot be tabulated as poisoning in many countries. Fire deaths and deaths coded to accidental, deliberate, or undetermined poisoning (n=702) decreased substantially with time, and by 2000 numbered 14 and 10, respectively. Accidental deaths declined from 151 in 1968 to 23 in 2000, but homicides and open verdicts varied from 5 to 20 per year, with no clear trend. Deaths attributed to carbon monoxide and to 'other gases, fumes or vapours' (mostly fire-related) totalled 2431 (84% of all poisoning deaths). Overall, 10% of these deaths were either certified as homicides or open verdicts. However, homicide or open verdict was recorded in half of the 47 fatal opiate poisonings. Opioids have now superseded antidepressants as the commonest agents encountered in fatal poisoning with drugs in children.     

A suicide using a homemade carbon monoxide "death machine"

Deaths related to carbon monoxide (CO) poisoning are common. Most represent accidents and suicides, and most result from CO production via the incomplete combustion of carbon-containing substances. Suicide via CO toxicity is not uncommon and typically involves the use of motor-vehicle exhaust as a source of CO. Presented herein is a case of suicidal CO poisoning in which the CO was produced via a chemical reaction between formic acid and sulfuric acid within a homemade device.