Harold L. Kaplan

Effects of Combustion Gases on Escape Performance of the Baboon and the Rat

In postcrash aircraft fires, only a few minutes are often available for egress. To assess the potential of selected combustion gases (CO, acrolein and HCl) to impair human escape, a signalled avoidance task was developed for use with the juvenile African Savannah baboon. After a 5-minute exposure, the animal was required to select and depress the correct lever to open an escape door and then to exit into the adjacent compartment of a shuttlebox. With CO, the EC50 for escape failure was 6850 ppm. Acrolein (12 to 2780 ppm) neither prevented escape nor affected escape times, despite irritant effects at all concentrations. Similar results were obtained with HCI (190 to 17,200 ppm) in that, despite severe irritant effects, all animals successfully performed the escape task. With a comparable shuttlebox and escape paradigm for rats, the EC50 of CO was 6780 ppm. Five-minute exposures to HCI (11,800 to 76,730 ppm) did not prevent escape but severe post-exposure respiratory effects and lethality occurred at 15,000 ppm and higher. In both species, escape time was not affected by HCI but a concentration-related increase in intertrial responses was evident. The data suggest that laboratory test methods for measurement of incapacitation of rodents may be useful in evaluating potential effects of atmospheres containing CO or irritant gases on human escape capability.

Modeling of Toxicological Effects of Fire Gases: I. Incapacitating Effects of Narcotic Fire Gases

Common fire gas toxicants fall into two major classes, narcosis-producing agents and irritants. It is desirable to model, mathematically, the effects of these common toxicants on humans exposed in a fire, and therefore, obviate the use of large numbers of laboratory animals in smoke toxicity testing. From a review of methodologies for assessment of the incapacitating effects of the nar cotic fire gases, it appears that rats are sensitive to approximately the same range of accumulated doses as may be deemed potentially hazardous to human subjects. This paper introduces an approach as a first approximation to the modeling of the incapacitating effects of the narcotic toxicants based on correla tion of observed effects with accumulated doses to which subjects are exposed.

Effects of hydrogen chloride on respiratory response and pulmonary function of the baboon

The effects of hydrogen chloride (HCI) inhalation on respiratory response during exposure and on pulmonary function during the 3 mo following exposure were studied in the baboon. Each of 4 groups of three anesthetized animals was exposed in a head-only mode for 15 min to air or one of three HCI concentrations (500, 5000, or 10,000 ppm). The acute respiratory response consisted of a concentration-related increase in frequency and minute volume, with a marked decrease in blood PaO2 at the two highest concentrations. The exposures did not cause significant alterations in any of the pulmonary function parameters measured at 3 d and 3 mo postexposure. Thus, nonhuman primates were able to survive short exposures to high concentrations of HCI without any significant effects on pulmonary function during the 3 mo after exposure. Furthermore, comparison of the response of primates and rodents suggests that the human is much less sensitive to the effects of HCI than the mouse.

Effects of irritant gases on avoidance/escape performance and respiratory response of the baboon.

The major toxicants in smoke are generally categorized as asphyxiants (hypoxia-producing agents) and irritants. Although the rodent appears to be an adequate model for evaluating the toxic effects of asphyxiant gases in man, the suitability of the rodent for evaluating the effects of irritant gases has not been established. In a study of the effects of irritant gases on escape performance of the baboon, exceedingly high concentrations of neither acrolein nor hydrogen chloride (HCl) prevented performance of the behavioral task; however, severe irritant effects were evident, even at lower concentrations. In a subsequent study of the respiratory response of the baboon to HCl, 15-min exposures to 5000 and 10,000 ppm (nominal concentrations) produced severe hypoxemia with a concentration-related increase in respiratory rate and minute volume. The difference between the rodent and the nonhuman primate in response to irritant gases suggests that the rodent may be an inadequate model for evaluating the toxicity of irritant gases to man and, therefore, the use of results of laboratory combust combustion tests to predict the toxicity of smoke in humans may lead to erroneous conclusions.

Acute Inhalation Toxicity of the Smoke Produced By Five Halogenated Polymers

The acute inhalation toxicity of smoke produced by five halogenated polymers used as electrical wire coatings was investigated in this study. The polymers in cluded two chlorofluoropolymers (Halar 500® and Halar 555®) and three fluoro polymers (Teflon 100® , Tefzel 200® and Kynar® ). The toxicity of each material was evaluated under flaming and nonflaming combustion using the NBS developmental protocol supplemented with measurement of incapacitation and analyses of the combustion atmospheres for HF, HCl and COF2.

Toxicity and the smoke problem

Abstract The production and toxicological effects of selected, major fire gases are reviewed. These gases include carbon monoxide, hydrogen cyanide, carbon dioxide, irritants and oxygen depletion, among others. The measurement of the toxicity of smoke is discussed relative to the parameters which need to be measured, in addition to some selected, existing test methods. These test methods are reviewed relative to their relevance to “real” fires, utility and appropriateness as standard tests.

Acute and Long-Term Effects of Polyvinylchloride (PVC) Smoke on the Respiratory System of the Baboon and a Comparison with the Effects of Hydrogen Chloride (HCl

The acute and long-term effects of smoke produced by flaming and nonflaming combustion of PVC were investigated in the baboon and com pared with those produced by HCl. Four groups of three anesthetized adult male baboons (Papio cynocephalus) were exposed for 15 minutes to air (con trols), flaming or nonflaming PVC smoke containing a targeted 5000 ppm con centration of HCl, or to HCl at a targeted concentration of 5000 ppm. The ani mals responded to flaming or nonflaming PVC smoke with an increase in frequency and minute volume, accompanied by decreased arterial pH and PaO2 and increased PaCO2 values. Although pulmonary function tests, CO2 chal lenge tests, or arterial blood gas measurements in PVC smoke-exposed animals showed sporadic differences from controls at 90, 180, or 360 days postexposure, the results did not indicate the development of impaired pulmonary function. These results were consistent with the absence of exposure-related respiratory tract pathology, although an inflammatory cell response was noted in the minor airways of one animal exposed to flaming PVC smoke. The effects of flam ing or nonflaming PVC smoke were generally similar to those of HCl, in dicating that HCl is retained in the upper respiratory tract, even in the pres ence of particulates in smoke.