CO Is Still Worst of Lethal Gases, Fire Casualties Seminar Learns

CO Is Still Worst of Lethal Gases, Fire Casualties Seminar Learns

Dr. Edward P. RadfordByron M. Halpin

Despite the presence of other lethal gases at a fire, carbon monoxide is still the major threat to life and many fire deaths can be prevented by adequate early warning systems.

These two conclusions were reached by speakers at the fire casualties conference conducted by The Johns Hopkins University Applied Physics Laboratory in Howard County, Md., last May 28 and 29.

In a survey of fire deaths in Maryland made by the J.H.U. Applied Physics Laboratory, there was “definitely CO poisoning ” in 50 percent of the fatalities, reported Byron Halpin of the Applied Physics Laboratory.

Victims on the move

He also stated that about 50 percent of the fire victims were on the move as death overtook them and people “could have been saved” if they had had an earlier warning. Only 40 percent of the victims were found in rooms where fires started, he disclosed.

The APL fire fatalities survey included 206 deaths throughout Maryland from September 1971 through December 1974. The fatalities occurred in 172 fires, of which 157 were residential and 15 were other classifications. There were no fatalities in this period in industrial fires. The sample population was restricted to fire or explosion victims who were subjected to an autopsy and who also died within six hours of the incident.

Halpin noted that while 49 percent of the Maryland fire victims in the survey were found in a bedroom, this room was not necessarily the room where the fire originated. Some 17 percent of the fatalities were found in a living room and 14 percent in a hallway or stairway. Other locations where victims were found were kitchen and bathroom, each 2 percent; closet, 3 percent; other, 10 percent; and unknown, 3 percent.

Children run and hide

Halpin remarked that children playing with matches “tend to run and hide” whenever fire starts. He commented that these children don’t know what fire can do. Primarily, they fear punishment by their parents and therefore, as far as safety is concerned, he advised, “we have to get the message to children and parents alike.”

In 52 percent of the deaths, Halpin reported, the cause of the fire was smoking and in two-thirds of the deaths involving smoking, evidence of alcohol also was found. The speaker commented that alcohol probably acts with a drug effect and slows reaction to the fire situation.

At least 60 percent of those who died in fires caused by smoking were initiators of the fires. Halpin also reported that smokers who escaped death in fires said they last handled smoking materials two to three hours before the fires were discovered.

At least four fatalities had heart attacks and these contributed to the start of the fires, Halpin stated.

Other fire cause figures were 7 percent careless handling of matches, 8 percent flammable liquids, 6 percent heating equipment, 4 percent electrical, 2 percent other and 10 percent unknown.

Initial materials ignited

Bedding and mattresses were involved in 35 percent of the fatal fires and sofas and chairs, 15 percent. These figures were for the initial material ignited.

In 5 percent of the cases, synthetics were the primary material ignited and there was no “concrete evidence” on the effects of these materials, Halpin reported.

The problem of hydrogen cyanide, said Halpin, is something that we know little about. He explained that there is “no concrete evidence that anyone has died” of the effects of hydrogen cyanide in a fire and it also is not known what hydrogen chloride and other irritants can do to the respiratory system in combination with other gases. Halpin suggested that there may be a need to determine whether a smoke casualty has suffered respiratory damage, and instead of being released from further care, he should undergo continued hospitalization.

Breathing apparatus use

Blood samples taken from Baltimore City fire fighters while still on the fireground indicated that the amount of carbon monoxide in the blood—carboxyhemoglobin—was not much different for those who wore breathing apparatus intermittently and those who did not wear breathing apparatus at all, reported Dr. Edward P. Radford, of The Johns Hopkins University School of Hygiene and Public Health. However, the carboxyhemoglobin was substantially less for men who wore breathing apparatus continuously at a fire.

Radford suggested that fire fighters may be unaware of carbon monoxide after knocking down a fire when they may be seriously exposed.

The blood carboxyhemoglobin for Baltimore fire fighters, Radford continued, was almost the same for heavy, light or moderate smoke. He suggested that smoke visibility may not indicate exposure to gases as well as we might like.

Flow chart depicts interrelation of the various segments of the investigation of fire deaths in Maryland made by The Johns Hopkins University Applied Physics Laboratory. Information gained from medical and chemical analyses and identification of toxic products produced under various fire conditions is expected to lead to fire detection and construction material specifications as well as recommendations for code changes, fire tactics, treatment of fire casualties and extended research.

If an adult is exposed to a 5 percent concentration of carbon monoxide, which Radford explained is encountered in fire situations, it will take one-half to one and one-half minutes for a 50-percent carboxyhemoglobin concentration in the blood. At 50 percent concentration, he added, the person breathes rapidly, is unable to coordinate his motions very well and does not think clearly. At a I percent CO concentration at a fire, it takes two and one-half to seven minutes to reach a 50 percent carboxyhemoglobin concentration, Radford said.

A 0.2 percent concentration can build up from a smoky fire some distance away from an individual in 12 to 35 minutes. He explained that the uptake of CO by children is somewhat more rapid than for adults.

Hydrogen cyanide, he pointed out, is very soluble in the body fluid whereas carbon monoxide is very insoluble. Because HCN is very soluble, it will be taken up by body fluids throughout the body, which provides a large reservoir. Therefore, Radford continued, hydrogen cyanide would probably have to be 10 times more concentrated than carbon monoxide before the same degree of effect on a person occurs. Radford commented that it is “probably relatively rare” for such concentrations to occur in a fire area.

He pointed out that irritant gases, such as aldehydes and phenols, will have an immediate effect on the human body because they become concentrated in the lungs instead of being distributed throughout the body.

Carbon monoxide deaths

Dr. Marshal L. Levine of The Johns Hopkins University School of Hygiene and Public Health reported that the largest proportion of people who died of carbon monoxide have a more than 60 percent concentration of carboxyhemoglobin in their blood.

“The more examinations we do, the more we can determine the specific cause of death,” Levine explained.

He noted that the long-term effect of short-term exposures of fire fighters was studied. The study included the pulmonary and vascular diseases and about 300 fire fighters were examined. However, there was not enough data for meaningful conclusions.

Levine noted that a great percentage of persons who become fire casualties seem to have some other problem—either medical, alcohol or smoking.

Evaluation of fire gases

Fire gases were evaluated by Dr. Paul W. Smith of the Federal Aviation Administration Laboratory in Oklahoma City, who discussed hydrogen fluoride, hydrogen chloride, nitrous oxide and hydrogen cyanide. He said that HCL “is a weak killer, however potent an irritant it may be.” Smith referred to hydrogen cyanide as still the most toxic of these four gases and commented that hydrogen chloride is “the only one of the four tested that produced delayed deaths” of rats.

He categorized nitrous oxide as “a potent irritant and a highly toxic material.” In air crash victims, Smith continued, only carbon monoxide and hydrogen cyanide can be satisfactorily measured. He said that in a Denver airliner crash, carbon monoxide was quite high in the victims as a result of burning cabin materials.

Dr. Marshal LevineDr. Paul W. SmithRoy AltmanDr. Russell A. Fisher

In tests with rats, Smith reported, there was faster incapacitation and death with a combination of hydrogen cyanide and carbon monoxide.

There is a synergistic relationship between hydrogen cyanide and carbon monoxide, reported Roy Altman of the Maryland medical examiner’s office. He said that hydrogen cyanide (HCN) increases the respiration rate, thereby causing more inhalation of CO and creating the synergistic effect. He commented that while 20 parts per million of HCN is considered safe as is 50 to 60 ppm for one hour, 2000 ppm of CO is dangerous in one hour. He added that 3 to 10 mcg/ml in blood is considered a lethal dose of HCN.

Identification of victims

Dr. Russell A. Fisher, Maryland state medical examiner, urged people at the scene of a fire fatality to look for miscellaneous items, such as jewelry and pieces of clothing around bodies, which may aid in identification. He said that sometimes even small bits of clothing that have survived a fire can be identified by a victim’s family, thereby corroborating other evidence.

Fisher described ways in which medical evidence or physical evidence can be used to identify bodies of fire victims. The fusion of skull sutures can indicate age, he explained, as the closing up process of skull sections reaches completion for different sutures at different ages. He noted that dental X rays can separate children within a year or so.

The Maryland medical examiner and forensic pathologist commented that the “very presence of so much heart disease among (fire) victims suggests that it has something to do” with fire deaths.

Coronary artery closure

Of 72 fire victims, half of them had significant coronary artery stenosis (closing or narrowing of the coronary arteries) said Fisher. He said that there is no way of evaluating the stress of a serious fire and its effect on a Fire victim who had coronary disease.

Fisher said he likes to think that a person will exceed a 50 percent carbon monoxide saturation before death occurs. He noted that one half of one percent CO will kill a person within half an hour. Stressing how easily it is for a person to be in a lethal carbon monoxide environment, Fisher explained that in a 10 X 16 X 10-foothigh room, only 20 ounces of wood or cotton need burn to produce a lethal level of carbon monoxide if the material is fully converted to gases.

Fisher explained that if blisters with fluid are found on the body, then life was present when the blisters were formed. He also explained that a slight crack of the skull need not have been done by a blow from some instrument but could be the result of the formation of steam inside the skull although the result may look like a crime had been committed. He also noted that if an autopsy discovers a major fat embolism in the lungs, then this is an indication that the person was alive during exposure to the fire.

Toxicological analysis

A toxicological analysis is made in all Maryland fire fatalities, Yale H. Caplan, Maryland chief toxicologist, told the conference. Also, a comprehensive drug screen is made from blood, bile and urine. Spectrophotometric methods are used for determining the level of carboxyhemoglobin and a gas chromatograph test is made for alcohol.

Caplan said that of the fire deaths among those over 15 years of age, a number which constituted 58 percent of the Maryland fire fatalities, 11 percent had significant alcohol content. He added there is no significant evidence that drugs are a substantial factor in fire deaths. As the alcohol levels increase, Caplan noted, the carboxyhemoglobin levels do not significantly go down.

The toxicological analysis in Maryland fire fatalities checks for alcohol, carbon monoxide and cyanide.

Dr. Jack H. Petajan of the University of Utah School of Medicine voiced the conviction that there is a toxieation syndrome connected with the conditions of burning plastics. Discussing his toxicity program involving polymeric and other materials, he said that there are two areas of comparison—one the severity of anoxia and two, unusual qualitative differences in the toxication syndrome.

Petajan stated that animals will regain their nerve responses when they have had up to 60 percent carboxyhemoglobin. Tests of rats indicate, he added, that “if an individual goes into anoxic shock, the mortality will be very high.”

He noted that an animal exposed to Douglas fir smoke has a lower carboxyhemoglobin than when exposed to pure CO because the irritation from the smoke reduces the animal’s breathing rate. He also noted that the desaturation of the animal is much faster with pure CO than with Douglas fir smoke.

Petajan said that temperature also is a factor in determining the qualitative products of combustion of plastics. He said that plastics can have entirely different intoxication syndromes at different heat fluxes. He referred to the toxicity of plastics as a complex subject.

Additives and toxicity

Dr. Merritt Birky of the National Bureau of Standards pointed out that sometimes when manufacturers use an additive to reduce the flammability of a product, the additive may increase the toxicity of the product. He also commented that it is not always easy to determine smoke hazards and noted the need for evaluation by both an analytical chemist and a toxicologist—not an analytical chemist alone.

In some products, it is possible to reduce the inherent flammability of a product and the goal is to determine the hazard of both fire-retardant and non-fire-retardant plastics.

In evaluating the hazards of burning plastics, Birky pointed out, the way the sample is decomposed, whether by flaming combustion or pyrolysis, is “very important.”

Richard BrightYale H. CaplanDr. Jack H. PetajanE. L. Quarantelli

Birky disclosed that the NBS laboratories have confirmed that there is no correlation between the amount of smoke and the amount of carbon monoxide.

Detectors discussed

The open interior design of American homes makes the use of heat detectors unsatisfactory for life safety, Richard Bright of the National Bureau of Standards told the conference. He also commentedthat the performance of heat detectors for life safety “will be purely marginal” but that they are acceptable for closed spaces.

Bright noted that all but one of the major building codes call for the use of smoke detectors.

In describing ionization and photoelectric product of combustion detectors, Bright pointed out that neither type will serve for all sizes of smoke particles. He explained that the ion chamber will detect smaller particles of combustion while the photoelectric type detector will detect the larger particles that are characteristic of the product of slow, smoldering fires.

Other differences

The ion chamber, Bright continued, seems to be more prone to falsealarming in the home that the photoelectric type. On the other hand, Bright added, the photoelectric type lacks sensitivity and may be too late in sensing a fire. He also noted that the smoke velocity makes a difference in the reliability of a smoke detector.

Bright commented that a significant level of protection can be obtained by using both smoke and heat detectors in a home.

Dr. J. Christian Gillin, a psychiatrist with the National Institute of Mental Health, talked about the function of sleep in regard to early warning systems. He commented that whether individuals are aroused from sleep depends on a stimulus—mostly sound—which has meaning of great importance to the individual. He remarked that the “functions of sleep are not very well understood.”

Reaction to disaster

People in general react much better to disastrous situations than is generally believed, Professor E. L. Quarantelli, co-director of the disaster research center at Ohio State University, told the conference. Unfortunately, he pointed out, the imagery of poor public reaction has practical consequences because public officials make decisions for handling disastrous situations on the basis of this misconception and as a result, they delay warnings about impending disasters—such as hurricanes.

Studies of response to sudden stress situations made in various countries, Quarantelli stated, show that people display a controlled rather than an impulsive reaction, they generally are not disorganized and usually they adapt their behavior to the situation. The speaker cautioned that this does not mean there are no problems in response to a disaster, but human behavior is not one of them—although there are individual incidents of functional misbehavior.

One reaction to a disaster situation, Quarantelli explained, is panic flight behavior, or the loss of self-control followed by nonrational flight. He explained that panic flight is associated with fear and a specific place of danger. Aspects of panic flight include fear of possible entrapment while there is still hope of getting out and the person involved has a great sense of powerlessness in the situation along with a feeling of isolation or aloneness. Quarantelli predicted that it is likely panic flight behavior will increase in the future because of such things as high-rise buildings, radioactive materials, etc.

Fire investigations

How fire investigations are conducted in Maryland was described by James C. Robertson, Maryland state fire marshal. Because he was a laryngitis victim that day, his talk was read by John H. Farrell, chief fire investigator on Robertson’s staff.

In the talk, Robertson explained how the fire officer is the first to investigate the cause of a fire and then calls in a trained state fire investigator who “should be a person who can later testify in a court of law” and can be qualified as an expert witness.

Fire investigators work with local policemen trained in investigation and if there is no evidence of any crime, the police investigator drops out of the fire investigation. Robertson pointed out that the fire scene should be secured as quickly as possible by the fire officer, who should then call a fire marshal, either county, city or state, as appropriate. If the scene is left unguarded, warned Robertson, the question of admissibility of evidence found there arises.

During questioning, Farrell stated that the length of a fire investigation is sometimes determined by the case load in the state fire marshal’s office. He added that “a fatal fire, of course, gets priority.” If there is an accidental death, Farrell pointed out, the investigation may disclose a cause that can lead to corrective steps to prevent similar deaths. In Maryland, Farrell noted, most fatalities occur in dwellings, many of them substandard. □ □

No posts to display