NBSIR 80-2077

It • DEVELOPMENT OF RECOMMENDED

TEST METHOD FOR TOXICOLOGICAL

ASSESSMENT OF INHALED COMBUSTION

PRODUCTS

MaTIOKAX. BOTttAtJ 09 TAKDXXM

tiMUjnr

NOV ? 4 1980

' 0.

c. V

Merritt M. Birky, Maya Paabo, Barbara C. Levin,

Susan E. Womble, Dolores Malek

Center for Fire Research

National Engineering Laboratory

National Bureau of Standards

U.S. Department of Commerce

Washington, DC 20234

September 1980

Final Report

Prepared for: Products Research Committee (PRC)

c/o Dr. John Lyons

National Bureau of Standards

Washington, DC 20234

U.S. DEPARTMENT OF COMMERCE, Philip M. Klutznick, Secretary

Luther H. Hodges, Jr., Deputy Secretary

Jordan J. Baruch, Assistant Secretary for Productivity, Technology, and Innovation

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director

TABLE OF CONTENTS

Page

LIST OF FIGURES iv

LIST OF TABLES V

Abstract 1

1. PROJECT DESCRIPTION 2

1.1 Scientific Background 2

1.2 Objective 2 1 . 3 Approach 2

1.4 Major Accomplishments 3

2. ANIMAL EXPOSURE SYSTEM AND TEST METHOD 4

3. MIXING CHARACTERISTICS OF THE EXPOSURE SYSTEM 4

3 . 1 Analytical Measurements 4

3.2 Toxicological Measurements 6

4. BLOOD CYANIDE MEASUREMENTS 6

4 . 1 Background 6

4.2 Experimental Details 7

4.2.1 Conway Microdiffusion/GC-ECD Technique 7

4.2.2 Head Gas/GC-NPD Technique 8

4 . 3 Animal Exposure to HCN 8

5. EVALUATION OF TOXICITY OF VARIOUS MATERIALS 9

5.1 General Toxicological Information 9

5.2 Toxicological Results 10

5.2.1 Douglas Fir 10

5.2.2 Modacrylic 11

5.2.3 Wool 11

5.2.4 Polytetrafluoroethylene (PTFE) 12

5.2.5 Flexible Polyurethane (GM-21) 12

6. SUMMARY AND CONCLUSIONS 12

7. REFERENCES 14

APPENDIX A. PROPOSED TEST METHOD FOR INTERLABORATORY

COMPARISON OF COMBUSTION PRODUCT TOXICITY A-1

iii
LIST OF FIGURES

Page

Figure 1. . 15

Figure 2. Flow diagram of analytical systems for combustion

products analysis , . 16

Figure 3. CO

2 concentrations from 10 mg/1 of Douglas fir . . . . Figure 4. HCl profiles in the exposure box , . 18

Figure 5. HCN profiles in the exposure box , . 19

Figure 6. Incapacitation of cannulated animals , . 20

Figure 7. Head space analysis of HCN , . 21

Figure 8. Solubility of HCN in water . 22

Figure 9. Change in blood cyanide content during exposure

to flaming modacrylic . 23

Figure 10. Restrainer for rats , . 24

Figure 11. Atmospheric and blood levels of carbon monoxide at

different mass loadings of Douglas fir decomposed

by flaming combustion . 25

Figure 12. Atmospheric and blood levels of carbon monoxide

and cyanide at different mass loadings of modacrylic

decomposed by flaming combustion , . 26

Figure 13. Atmospheric and blood levels of carbon monoxide

and cyanide at different mass loadings of modacrylic

decomposed in the non-flaming mode , . 27

Figure 14. Atmospheric and blood levels of carbon monoxide

and cyanide at different mass loadings of wool

decomposed in the flaming mode . . 28

Figure 15. % incapacitation and % death at different mass

loadings of wool in the flaming mode . 29

Figure 16. % incapacitation and % death at different mass

loadings of wool in the non-flaming mode . 30

Figure 17. PTFE - post exposure death , . 31

Figure 18. Post exposure mortality from non-flaming flexible

polyurethane foam, (GM-21) , . 32

Figure 19. Toxicity (EC^q + EC^q) of combustion products from

PTFE, modacrylic, and wool decomposed in both flaming

(F) and non-flaming (NF) modes as compared to that of

Douglas fir 33

XV
LIST OF TABLES

Page

2 Table 1. Data used in calculation of (Chi) test of

independence of order of incapacitation and

animal position in flaming experiments 34

Table 2. Analytical methods for measuring blood cyanide 35

Table 3. Auto- ignition temperatures and temperatures

used in the flaming and non-flaming modes 36

Table 4A. Summary of test method data 37

Table 4B. Summary of test method data 38

Table 5. Control blood values 39

Table 6. Experimental temperatures of combustion and

toxicity results 40

Table 7. Analytical and blood data at EC-q and LC-q

concentrations 41

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DEVELOPMENT OF RECOMMENDED TEST METHOD FOR

TOXICOLOGICAL ASSESSMENT OF INHALED COMBUSTION PRODUCTS

Merritt M. Birky, Maya Paabo, Barbara C. Levin,

Susan E. Womble, Dolores Malek

Abstract

The objective of the project supported by PRC was to develop

a test method for measuring the toxicity of combustion products

from polymeric materials including cellular plastics . The development of such a test procedure was considered an essential first

step to determine the hazard to life when cellular plastics are

involved in fire.

As a result of this work, a test procedure was developed.

It consists of 3 major elements; (1) combustion system, (2) chemical analysis system and (3) animal exposure system. Two

biological endpoints obtained from the exposure are: (1) incapacitation in 30 minute exposure period, and (2) lethality in 30 minutes

plus 14 days post exposure.

The test apparatus has been evaluated to determine mixing

rates and loss of reactive chemicals in the exposure chamber.

In addition, a statistical evaluation of the experimental results

demonstrated that order of incapacitation was independent of

animal location.

Evaluation of a limited number of different materials that

produce different toxicological syndromes has demonstrated the

utility of all 3 endpoints. Two natural polymers (wood and wool)

and 2 synthetic materials (modacrylic and PTFE) have been studied

in detail. In addition, preliminary data have been obtained on a flexible polyurethane foam (GM-21)

.

Key words: Combustion; fatality (LCcq) ; hydrogen cyanide;

incapacitation; inhalation; test method; toxicology.

1
1.11. PROJECT DESCRIPTION

Scientific Background

Fire statistics show that approximately 70% of the fire fatalities in

the U.S.A. are attributed to smoke inhalation. An extensive revjew of the

scientific literature on the toxicity of combustion products [1] showed

that a great deal of effort had been expended in trying to determine the

toxic hazard associated with fires and to correlate this hazard with the

chemical analysis of pyrolysis products. In the review, it was pointed out

that the conclusion reached by those authors who conducted such analytical

measurements was that more measurements were required before one could

establish the toxicity of these products.

As a result of this information and experience in the field, it became

apparent that if progress is to be made in our understanding of the toxicity

of fire products, a judicious combination of chemical analysis and exposure

of living organisms is required. Living organisms are required to determine

the integrative effects of the large number of chemical species produced

from a single polymeric material when it undergoes thermal decomposition.

Furthermore, the evaluation of this complex mixture is complicated by the

fact that various toxic products affect living organisms in different ways

and in many cases these effects are unknown. Chem.ical analysis of selected

toxic products is considered important to further our understanding of the

toxic syndrome identified through the use of living organisms.

1.2

Objective

The objective of this study was to develop the measurement tools, in

this case, a standardized procedure, by which the toxicity of combustion

products could be measured. While the PRC program was limited to cellular

plastics, our objective was to develop the basis for a toxicity protocol

which was not limited to cellular plastics, but included all polymeric

materials, both natural and synthetic.

1.3

Approach

The details of the test method are provided in Appendix A. In summary,

the method consists of exposing 6 adult male rats in the head-only mode for

a period of 30 minutes. The combustion products are generated in a cup

furnace in the flaming and non-flaming modes in the bottom of a nominal

200 liter exposure chamber. Incapacitation, as defined by the hind-leg flexion behavioral model, and percent lethality, including deaths during the 30

minute exposure period and for a 14 day post-exposure period, are determined

as a function of mass loading from which the LCc» value is statistically

determined. Blood carboxyhemoglobin saturation^associated with the exposure

is measured. Rats were chosen as the animal species rather than mice to

provide a sufficient blood supply for COHb determinations as well as other

selected blood parameters.

1 Numbers in brackets refer to the literature references listed

at the end of this report.
Heat stress and oxygen deprivation are eliminated as toxicological factors

by chamber temperature and oxygen concentration control in order to reduce

the scope of the problem to a manageable size. In addition, the static mode

of exposure was chosen to reduce the preferential loss of low vapor pressure

toxic species when transporting these species from the combustion chamber to

the exposure chamber.

Combustion of the material in the exposure chamber was considered the

most ideal solution as long as the environmental temperature was controlled

to eliminate heat stress on the animals.

It was further decided that incapacitation should be an endpoint as well as death. Incapacitation was considered important since one would like

an early indication that the combustion products are causing a toxicological

problem and since investigations of fire fatalities indicated that in many

cases the fire victims had made an attempt to escape. Since no incapacitation

model appears to be universally responsive to the effects of all toxic chemicals, death was considered an important endpoint as well.

After due consideration of the above factors, a test apparatus and method

were proposed. A copy of the proposed test method is attached as appendix A.

1.4 Major Accomplishments

During the period of PRC support, the following accomplishments have

been realized:

(1) the development of an animal exposure system for use

in the proposed test procedure,

(2) the determinations of the mixing characteristics of

the system, both analytically and toxicologically

,

(3) the development of a reliable analytical technique

for hydrogen cyanide in the fire gases,

(4) the development of a more rapid technique for the

measurement of blood cyanide and

(5) the determinations of the toxicity of the combustion

products of samples of Douglas fir, wool, modacrylic,

polytetrafluoroethylene and a flexible polyurethane.

The above accomplishments will be reviewed in detail in the following

discussion. However, it should be noted that this is a progress report

toward the development of a toxicity protocol and not a completed study.

For example, while time to incapacitation is required in the proposed

test method, time is not reported in this study pending further research on

time effects versus concentration effects. Incapacitation is reported on a mass loading basis similar to the lethality end-point.

3
2 . ANIMAL EXPOSURE SYSTEM AND TEST METHOD

The animal exposure system is shown diagrammatically in figure 1. The

chamber is constructed of 1.25 cm (1/2 in) polymethylmethacrylate (PMMA) and

measures 122 cm (48 in) long by 46 cm (18 in) high by 36 cm (14 in) deep in

inside dimensions. This chamber provides a nominal volume of 200 liters.

Combustion products are generated in a small cup furnace inserted in the

bottom of the chamber at the left end as noted, in figure 1. The furnace is

of the design reported by Potts and Lederer [2]

.

For this test system, mass

loading of combustion products is defined as the weight of the material added

to the furnace in milligrams divided by the volume of the exposure chamber

in liters (mg/1)

.

Various radiant heat systems were tried without success. The major difficulty was designing a system that was compatible with the animals, that is,

all systems tested produced an unacceptable temperature rise in the exposure

chamber. The first system that was tested was a radiant panel (quartz-iodide

lamps) that was placed outside the chamber and the radiation was directed

through a quartz window.

A second radiant system was placed inside the chamber where the top of

the furnace is located. This system consisted of a truncated pyrex cone

coated with a reflective layer and wrapped with a resistance coil on the

inside surface of the cone.

Again, the heat losses were large enough that the chamber temperature

rose beyond the 35 °C environmental temperature limit specified in the proposed test method.

The proposed test method, a description of which is attached as Appendix

A, details the apparatus and procedure that was used for the combustion product toxicity determinations. The method may undergo further modifications

as more materials are evaluated and as the results of an interlaboratory

evaluation of the method by nine laboratories are analyzed.

The gas analysis system for CO, CO^ and 0- is shown by figure 2. The

CO and CO

2

are measured by continuous flow commercial infrared analyzers.

The 0» is determined by a galvanic cell. These gas concentrations are

measured continuously and since these are routine measurement techniques,

they will not be described further except to note that the 0.5 1/min. gas

stream used for this analysis is returned to the exposure chamber.

3. MIXING CHARACTERISTICS OF THE EXPOSURE SYSTEM

3.1 Analytical Measurements

Prior to the exposure of animals in the proposed test method, extensive

analytical measurements were made in the chamber at various locations to

determine the mixing characteristics of the system. As noted in figure 1,

CO

2

, HCl and HCN determinations were made at three elevations (5 cm from top

Note; Certain commercial equipment, instruments, or m.aterials are

identified in this paper in order to adequately specify the experimental procedure. In no case does such identification imply recommendation or endorsement by the National Bureau of Standards, nor does

it imply that the material or equipment identified is necessarily the

best available for the purpose.

4
and bottom and at center) along the front face of the chamber in a vertical

line between animal ports 3 and 4. In addition, an HCN measurement was made

5 cm from the bottom of the chamber at the far end.

The results of the CO- measurements taken when 10 mg/1 of Douglas fir

was thermally degraded at ?40®C (non-flaming) are shown in figure 3. For

this analysis, samples were collected in pre-evacuated bulbs and analyzed

gas chromatographically

.

As indicated in figure 3, mixing occurs very rapidly in the chamber and

there were no significant gradients between the three levels under the test

conditions. Similar results were obtained with 20 and 30 mg/1 samples.

Repeated combustion of wood samples at a fixed loading was carried out

to determine the repeatability of the system. In this case, carbon monoxide

was measured in addition to CO- and reproducible results were obtained.

Continued measurements of CO from other materials have confirmed this finding.

A poly (vinylchloride) was degraded at 475°C in the non-flaming mode to

generate HCl in the exposure chamber. These measurements were designed to

determine if concentration gradients existed in the system when a reactive

gas such as HCl was present and to establish the adsorptivity of HCl on the

PMMA used for construction of the exposure chamber.

The HCl analysis was made with an ion selective electrode. The technique

for trapping the gaseous HCl was similar to that described by O' Mara [3]

.

10 ml disposable plastic syringes were used to withdraw 5 ml gas samples

simultaneou|ly at the three sampling ports. Once the gas was in the syringe,

5 ml of 10 HCl solution was drawn into the syringe and the syringe was

vigorously shaken. The scrubbing was repeated three more times.

The dissolved HCl was measured with a chloride ion-selective electrode

(Orion 92-17A )

2

in conjunction with a double junction reference electrode

(Orion 90-02)

.

Emf measurements were made with a digital pH meter that had

been calibrated with standard HCl solutions in the range of 10 to 5 x 10 M.

The concentration of HCl in the gaseous samples was calculated using calibration curves obtained by plotting electrode potentials versus the log of

HCl concentrations

.

The efficiency of the syringe sampling technique was checked by comparing it with a standard sampling procedure employing midget impingers and a large volume of gas. Two liters of HCl reference gas (4000 ppm) were collected in two impingers filled with 15 ml of 2% NaOH. After sampling, the

chloride content of the combined trapping solution was measured with the

ion-selective electrode. The efficiency of the syringe sampling technique

was found to be 82 + 2%.

The results of two HCl measurements in the test chamber are illustrated

in figure 4. The broken line is the theoretical quantity of HCl based on

formulation information. In the first experiment, the HCl concentration was

lower in the upper position than in the lower two, unlike the second experiment where the concentration was the same in all three positions. There was

some evidence of inhomogeneity as the initial HCl concentration in the second

experiment was above the theoretical amount (based on 92% resin content)

.

As evidenced by the rate of decrease in HCl concentration and comparison

with theoretical yield, adsorption does not appear to be unreasonably large

suggesting that this chamber is suitable for the exposure system.

As noted in figure 1, cyanide determinations were also made at three

levels. In this case various nitrogen containing polymers were used. The

results of measurements when wool was thermally degraded at 625°C (nonflaming) are shown in figure 5. In this figure, two separate determinations

5
at different mass loadings (sample weight in furnace) are illustrated. As

noted in this figure, there was no significant stratification of HCN in the

box and mixing was good within the 10 minute -sampling period.

The analytical procedure for the HCN determinations was based on a gas

chromatographic technique utilizing a nitrogen specific detector. The

details of this technique have been published [4]

.

These measurements on CO

2

/ HCl and HCN, although limited, show that

mixing in the chamber is rapid compared to the 30 minute exposure period and

that stratification and absorption do not appear to be problems, at least

for these products. One would expect that other products would have behave

similarly and that there would not be concentration gradients. This has been

proven by subsequent toxicity studies detailed in the following section.

3.2 Toxicological Measurements

To demonstrate the overall adequacy of mixing in the inhalation chamber,

a statistical analysis [(Chi)^ test of independence] of both flaming and nonflaming experiments was made to determine if the time order of incapacitation

was independent of animal location. Table 1 shows the data used to calculate

the (Chi)^ test of independence of the order of incapacitation and animal

position in 45 flaming experiments. Flaming data were analyzed separately

from non-flaming to determine if radiation effects (heat stress) were having

an effect on the animals in addition to possible concentration gradients.

This analysis of the data showed that the order of incapacitation was

statistically independent of the animal position in both the flaming and

non-flaming experiments. The experimental variation noted was not significant

at the p = 0.05 level.

However, the statistical analysis did show that cannulated animals do

have a tendency to be incapacitated first. This is shown by figure 6. Two

animals out of six used in each experiment were cannulated. If the cannulated

animals had an equal probability of being incapacitated first, the data would

show that 33% of the time a cannulated animal would be first as shown by the

solid line in the bar graph. However, a cannulated animal was incapacitated

first 74% of the time. This analysis shows that the cannulated animals are

slightly more susceptible to the effects of toxic products.

More importantly, the statistical analysis of the data shows that within

the limits of the data, all six positions are equivalent. These findings

confirm the extensive analytical data.

4. BLOOD CYANIDE MEASUREMENTS

4 . 1 Background

Past efforts to evaluate the toxicological importance of HCN in the

fire environment had been handicapped by the lack of a rapid and accurate

technique for determination of cyanide in blood. Several methods are

available for blood cyanide and these our outlined in table 2. They all

require relatively large volumes of blood (several milliliters) for the

isolation step which itself is time consuming (2-3 hours) . In these

methods, the cyanide is separated from blood and analyzed by a number of

techniques

.

In the course of exposure of animals to degradation products of modacrylic, two methods were used for determining blood cyanide. First, in the

non-flaming modacrylic exposures, blood cyanide was determined by a modification of a gas chromatographic method of Valentour [5]

,

In this case the

6
cyanide was isolated from the blood utilizing the micro-diffusion technique

of Feldstein and Klendshoj [6]

This multistep process uses Conway microdiffusion dishes for isolation

of volatile HCN. The cyanide is converted to cyanogen chloride with chloramine-T, extracted with n-hexane and detected by gas chromatography using an

electron capture detector. In addition to the time required for carrying

out the procedures, the main disadvantage of this technique is that only one

blood cyanide determination can be made per animal.

In combustion toxicity studies, it is desirable to take repeated blood

samples during an exposure in order to determine blood cyanide content at

the time of incapacitation as well as at the time of death. This requires

a rapid and simple blood cyanide analysis method using small volumes of

blood. Such a method was developed based on the analysis of head gas above

an acidified blood sample. This second technique was used for flaming

modacrylic studies.

This technique involves isolation of HCN by acidification of a small

blood sample (0.2 ml) in a gas tight container, followed by analysis of HCN

in the head gas by the same gas chromatographic technique as used for environmental HCN.

4.2 Experimental Details

4.2.1 Conway Microdiffusion/GC-ECD Technique

Two ml of O.lN NaOH is added to the inner wall of a Conway microdiffusion dish. A 2 ml aliquot of the blood sample is placed into the outer

chamber to which 2 ml of IN tartaric acid is added. The dish is immediately

sealed with a glass cover. The acid and blood are mixed with gentle swirling

and allowed to stand at room temperature for 2 hours. The alkaline NaCN

solution is pipetted from the center well and subjected to wet chemistry for

converting the cyanide to cyanogen chloride.

To 1 ml of NaCN solution in a septum sealed vial, 2 ml of n-hexane, 1 ml

of IM NaH

2 PO., and 1 ml of chloramine T solution (0.26%) are added. The vial

is shaken for 30 seconds and allowed to stand for 5 minutes for the n-hexane

layer to separate. All reagents and the reacting mixture are cooled in an

ice bath.

The HCN (in the form of cyanogen chloride in the hexane layer) wasquantified by gas chromatography. A gas chromatogram equipped with a "^Ni

pulsed linearized electron capture detector was used for this purpose.

1 ul samples of the hexane layer were injected on to a 6 ft. x 1/4 in. O.D.

stainless steel colvimn packed with 7% Halcomid M-18 on Anakrom ABS, (90-100

mesh) . The column was operated isothermally either at 75 or 85 ®C. The

injection port was at 150°C and the detector was kept at 300®C. Five percent methane in 95% argon was used as a carrier gas at a flow rate of 60

ml/min. Chromatograms were traced with a recorder and the peak areas

determined with a digital integrator.

The GC system was calibrated with standard aqueous cyanide solutions

^

* 7^^ ug/ml) which were subject to similar wet chemical conversion steps. The first n-hexane solvent peak was used as an internal standard and the ratio of the peak heights of cyanogen chloride to n-hexane was related to HCN concentration in blood using a standard KCN solution of similar con- centration.

efficiency of the microdiffusion step was evaluated by spiking blood samples with KCN solutions in the range of 0.1 to 5 ug/ml and sub- jecting the samples to blood cyanide analysis procedure. Standard curves

7
were calculated based on the detector response to aqueous reference solutions containing KCN. Spiked blood analyzed by microdiffusion technique

gave results lower than the theoretical amount. The average recovery

efficiency of the Conway microdiffusion technique was found to be 73.1% with

std. dev. + 6.3. Blood cyanide values for exposed animals were corrected

for this recovery efficiency.

4,2.2 Head Gas/GC-NPD Technique

In this technique, 0.2 ml of blood is added to a 3 ml vacutainer containing 0.2 ml of 85% H^PO,, mixed with a vortex mixer, and equilibrated for

1 hour in a waterbath at 60°C. The HCN in the head gas was sampled with a 100 ul gas-tight syringe and quantified by gas chromatography using an alkali

flame detector. The experimental parameters were the same as used for the

analysis of environmental HCN in gaseous degradation products [4]

.

The efficiency of liberation of HCN from blood matrix under the experimental conditions was examined by comparing HCN concentrations in the head

space of acidified O.lN NaOH solutions and blood samples, both spiked with

CN in the range of 1-10 ug/iril. A linear relationship was obtained between

alkali flame detector response and cyanide concentration in the solutions

for both substrates, as shown by figure 7. Repeatability of duplicate

analysis was better than + 6%. Lower detection limit was estimated to be

about 0.2 ug CN/ml. The portion of HCN liberated into the head space was

12.5% (std. dev. + 0.8%) for aqueous solutions and 9.4% (std. dev. + 1.3%)

for blood samples.

The recovery of HCN from blood by the head gas technique was 75% of that

from aqueous media. However, to avoid the uncertainty of this correction

factor, spiked blood containing 10-20% H„0 was used for standardization

purposes when cyanide levels were determined in blood of exposed animals.

The results of the head gas measurements permit the calculation of the

partition ratio between HCN in the vapor phase and HCN in water and blood

at 60 °C. The partition ratio is expressed as:

mg HCN/1 solution

1 = mg HCN/1 gas

and was approximately 125 for water and 160 for blood. These results are

compared with solubility data obtained from the literature for HCN in water

(see figure 8) over a range of temperatures.

4 . 3 Animal Exposure to HCN

The two techniques (head space and microdiffusion) described in the

previous sections were used for determination of blood cyanide during exposure of animals to degradation products of modacrylic. The product load

was varied between 2-5 mg/1 which resulted in a concentration of HCN in the

range of 100-275 ppm.

During non-flaming modacrylic experiments, the animals were sacrificed

at the end of 30 minute exposure and blood samples were taken for cyanide

determinations via the Conway diffusion technique. The average blood-cyanide

values ranged from 0.62 to 2.73 ug/ml. The average deviation for five

measurements with duplicate determinations was + 8.5%.

During flaming modacrylic experiments, the blood for cyanide determinations by the head gas technique was withdrawn from the cannula close to the

time of incapacitation and near the end of the 30 minute exposure. The

average blood cyanide levels varied between 1.91 and 6.53 ug/ml. The reproducibility of the head gas technique was not as good as for the Conway diffu8
sion method. The average deviation for 10 blood samples with duplicate

determinations was + 21%. Results of blood-cyanide concentrations as a function of exposure time are shown in figure 9. In this figure, the arrows

indicate time of incapacitation.

The toxicological interpretation of blood cyanide findings will be discussed in section 5.2.2.

5. EVALUATION OF TOXICITY OF VARIOUS ti^TERIALS

5.1 General Toxicological Information

As indicated earlier, toxicological and analytical data have been

obtained for Douglas fir, wool, modacrylic and PTFE using the proposed test

procedure. Douglas fir was obtained as rectangular sheets approximately

30 cm X 23 cm x 1.9 cm and was cut into a cube of desired weight before each

experiment. Wool was obtained as a roll of washed, unbleached and unwoven

fibers. Modacrylic was a knit fabric. Both wool and modacrylic were cut

into a piece of desired weight before each experiment. PTFE, a powder, was

weighed on an analytical balance to insure precise weighing of the small

quantities needed. Preliminary data have also been obtained for a flexible

polyurethane foam (GM-21)'^. The temperatures at which these data have been

obtained are tabulated in table 3. Polystyrene (GM-51) is listed in this

table, but no toxicological data are reported here.

As specified in the test procedure, the animals are exposed head only.

The restrainer tube used to hold the animals is illustrated in figure 10.

These restrainers position the animals in the exposure chamber at the ports

shown in figure 1. The details of the test procedure are given in appendix

A.

Fisher 344 albino male rats were obtained weekly. The animals weighed

224-250 grams upon arrival and were kept at least 10 days before experiments

in order to acclimate to our laboratory conditions of 22®C and 50% relative

humidity. They were weighed during the laboratory acclimation period to

assure normal weight gain.

Each arrival of animals was divided into experimental and control groups

i.e., a usual weekly arrival consisted of 28 animals, 24 were used for experi

ments (4 experiments, 6 animals each) and 4 were kept as controls. All

animals were housed individually in suspended stainless steel wire cages in

a temperature and humidity controlled room. Twelve hours of fluorescent

lighting per day were controlled by an automatic timer. Food and water were

consumed ^ libitum . Fresh bedding was provided three times a week. All

animals surviving exposure were kept 14 days and weighed 5 days per week.

The types of data that are recorded during the experiments are shown in

tables 4a and 4b. These tables provide for the tabulation of all data except

the concentration of various gases in the exposure chamber.

Blood measurements are performed on two of the six exposed animals.

These two animals are cannulated at least 12 hours prior to the experiment.

The cannula, which is placed in the left femoral artery, allows arterial

blood to be drawn before, during (at 15 minutes and at incapacitation) , and

just prior to the end of the exposure.

Standard reference materials available from PRC.

9
Nine different blood parameters are analyzed. Total hemoglobin (THb)

,

carboxyhemoglobin (COHb) , oxyhemoglobin (02Hb) , methemoglobin (MetHb) and

volume % oxygen are measured by a co-oximeter which was calibrated for rat

blood. The pH, pCO^ and pO^ were measured on a blood gas analyzer. This

instrument was calibrated before each experiment with a certified calibration

standard clinical blood mixture made for in vitro diagnostic use. In addition, blood cyanide was measured by the procedures described in sections 4.2

and 4.3.

At the beginning of an experiment before the sample is introduced into

the furnace, arterial blood samples are taken from the two cahnulated animals

for control values. The control values for various arterial blood parameters

are tabulated in table 5 and compared with similar values obtained at the

University of Utah.

The major differences in the control values between the two laboratories

are partial pressures of CO^ and O^. The Utah values are lower due to a difference in atmospheric pressure, as Salt Lake City is situated at an

elevation approximately 5000 ft. and Washington is approximately at sea level.

5.2 Toxicolgical Results

The results of the toxicity measurements for the four materials that

have been evaluated under conditions of non-flaming and flaming combustion

are summarized in table 6. The temperature at which the material is degraded

is listed in column 2 of the table. The third column (EC^q) is the mass

loading of combustion products per unit volume required to^cause incapacitation of 50% of the animals within the 30-minute exposure period. The 5th

and 4th columns lists the mass loading that leads to lethality of 50% of the

aniioals (LCc«) in 30 minutes and 30 minutes plus 14 days post exposure, respectively. ^While the residue in the furnace is determined by weighing, it

is not taken into account for calculating the mass loading. The results of

measurements on each of these materials will be discussed individually below.

5.2.1 Douglas Fir

A graph of the carbon monoxide concentrations and the resulting carboxyhemoglobin values versus different mass loading of Douglas fir tested in

flaming mode are shown in figure 11. The mass loading for EC_^ and LC-^ are

overlayed as vertical lines on the figure. The carbon monoxide values^are the

average concentrations for the 30-minute exposure period.

Animals exposed to the flaming combustion of Douglas fir showed very high

levels of carboxyhemoglobin (COHb). In figures 11-14, COHb levels are indicated by circles; open circles mean that the animal died during the 30-minute

exposure. Other blood parameters besides COHb values changed during the

exposure. For example, the O^Hb and partial pressure of oxygen (pO^) declined

as the COHb increased. In addition, the partial pressure of CO^ (pCO-)

increased and pH decreased as a result. All of the above blood^parameters

are for arterial blood.

From figure 11, one notes that for a 30-minute exposure, the ECc^

occurred when there was about 1800 ppm of CO and an average COHb concentration of 75%. For the LC^q, the average COHb value was about 85%. This data

plus the finding that there were no post-exposure deaths indicates that the

predominate cause of incapacitation and death from exposure to the flaming

combustion products of Douglas fir is most likely carbon monoxide.

Results of non-flaming experiments with Douglas fir are shown in tables

6 and 7. As noted in these tables, the flaming mode is less toxic with all

deaths attributed to CO.

10
5.2.2 Modacrylic

Analysis of the analytical and toxicological data for flaming and nonflaming combustion of the m.odacrylic fabric tested is shown in figures 12

and 13, respectively. In these figures, hydrogen cyanide environmental levels

and blood cyanide are also recorded.

It is obvious, from environmental CO and COHb concentrations, that carbon

monoxide is not a very significant toxicant in the cause of the incapacitation

or death of the animals exposed to modacrylic decompositions. For example,

COHb never exceeded 25% saturation. However, in the flaming mode, (figure 12,

table 7) the average HCN concentration at the calculated ECcq is about 125 ppm

and the corresponding average blood level is about 2.5 ug/ml. The average

concentration of HCN for the calculated 30-minute LCcq level is about 215 ppm

with a corresponding blood level of 4 ug/ml. Under non-flaming conditions

(figure 13, table 7), the environmental HCN concentrations at the EC^q and

LCgQ were similar to those values found under flaming conditions. However,

the blood cyanide levels found in the non-flaming mode were approximately half

those found in the flaming mode. This apparent discrepancy may be due to

analytical uncertainties in the blood cyanide measurements or to an increased

toxicity from different combustion products produced in the non-flaming mode.

The presence of cyanide in the blood is indicative of exposure to atmospheric cyanide, however, the precise blood level may not reflect the magnitude

of the exposure or the extent of the toxicological problem. The reason for

this is found in the mechanism of cyanide toxicity.

First of all, cyanide is not toxic while in the blood. Cyanide toxicity

results from interfering with the electron transport system within the cells

of the tissues. It does not prevent the oxygenation of hemoglobin nor does

it interfere with the metabolism of the red blood cells. Therefore, if

cyanide is kept in the blood, it is essentially in a non-;^^xic state. In

fact, cyanide can be kept in the blood by changing the Fe oxidation state

(hemoglobin) to the Fe state (methemoglobin) which will bind the CN ion.

This is part of the procedure used to detoxify victims poisoned by HCN.

It should be clear from the above that it is the total body burden

resulting in a given tissue level which accounts for the toxicity of cyanide.

Furthermore, this distribution is time dependent. That is, a low environmental concentration will provide more time for HCN to be distributed throughout the body fluids and to tissues, resulting in a lower blood level at

incapacitation or death. A higher environmental concentration will saturate

both the blood and the tissues rapidly, thus resulting in a higher value at

incapacitation or death. Reference to the data shown in figure 9 suggest

that blood cyanide measurements are insufficient to demonstrate a causal

relationship between death and inhaled cyanide. This suggests that using

blood cyanide levels to determine cause of death in fire victims may be

misleading. Experiments on pure cyanide and its distribution between the

blood and other body tissues may help to resolve this problem.

5.2.3 Wool

The toxicological results from the flaming wool exposures are illustrated

in figure 14 and summarized in table 6. In this case CO is somewhat higher

than in the modacrylic, with the CO and HCN concentrations sufficient to be

of some toxicological significance but neither alone being sufficient to

cause incapacitation.

Figures 15 and 16 are plots of total mass loading vs. toxicological

response for flaming and non-flaming combustion. The curves were drawn as

a best fit to the data points. However, the values recorded in table 6

were obtained from a statistical analysis of the data according to the method

11
of Litchfield and Wilcoxon [7]. In the case of flaming wool (fig. 15) it is

interesting to note that the animals in a given experiment were either all

incapacitated or none were incapacitated thus producing a very steep-dose

response curve. The difference in product loading between zero incapacitation

and 100% incapacitation was 22.1 and 22.6 mg/1.

5.2.4 Polytetrafluorethylene (PTFE)

The PTFE produced by far the most toxic combustion products of any of

the materials tested. All deaths occurred post-exposure. No analysis of

carbon monoxide and other gases was made. The fixed gases were not measured

because of the possibility of damaging the gas cells in the non-dispersive

IR equipment.

The fatality data for PTFE are summarized in table 6 and in figure 17

in which the time of death and number of deaths is recorded with the sample

mass loaded. Incapacitation did not occur during the 30 minutes of the

exposure at these concentrations. The highest COHb recorded with this

material was 2.4%. The cause of death has not been established at this time,

however, the mode of death is suggestive of a CNS (Central Nervous System)

type of agent. Review of past work of the toxicity of thermal degradation

products of PTFE indicates that the toxicity is attributed to a hydrolyzable

fluoride [1]. However, we have not identified the toxic species.

5.2.5 Flexible Polyurethne (GM-21)

While the studies on non-flaming GM-21 are incomplete, preliminary

analytical and toxicological results show that hydrogen cyanide is not a significant factor. Even at 30 to 40 mg/1 mass loading, the HCN levels never

exceeded 30 ppm. Carbon monoxide was elevated and COHb values were in the

range of 55%. This was not an incapacitating level or a lethal level for the

30-minute exposure period, however, post exposure deaths did occur.

The fatality data are shown in figure 18. The cause of death was

believed due to severe respiratory distress with some of the animals dying

as long as 15 days after exposure. In all cases, the animals were weighed

daily and as a result of the exposure many lost considerable weight (i.e. as much as 100 grams)

.

Further analysis of data and more experiments are planned. We also

plan to do histology of the respiratory tissues of the exposed animals.

6. SUMMARY AND CONCLUSIONS

The results of measurements of the toxicity of the combustion products

from the four materials that have been tested according to the prescribed

toxicology protocol are summarized in table 7 and figure 19. As indicated

earlier, in our experimental system the primary toxicity of the combustion

product from the modacrylic fabric can be attributed to HCN. In the case of

the wood, it is not so clear. In fact, the average concentrations of HCN at

the EC__ level for the non-flaming wool is almost identical with the LC_-

(30 minV) concentration of HCN in non-flaming modacrylic. There are at^Ieast

two possible reasons for this difference in the toxicological response to the

combustion products of wool and modacrylic at the same HCN concentration;

(1) an additional unidentified toxic product could be generated in the nonflaming combustion of the wool that somehow protects the animals from HCN.

Additional research is required to elucidate these differences.

In figure 19, the EC^q and two LC^q values are compared for the four

materials. This comparison shows that^under the test conditions used in

these experiments the combustion products from the modacrylic fabric tested

12
are about an order of magnitude more toxic than wood and that the PTFE powder

used is more than a hundred times more toxic than wood. This correlation

appears to be true for all the end-points that were used in these experiments.

It is clear, from these data and previous dose-response calculations, that

for the materials studied the EC-q and the LC-q values give above the same

information. That is, the incapacitation model is not providing significantly

enhanced sensitivity to detect the toxicity of combustion products. This

conclusion should not be extended to all materials until data on other

materials have been obtained. However, this data does suggest that the proposed 'test method can be simplified by reducing the amount of incapacitation

data that is required.

Overall, the proposed test method gives repeatible results. Mixing in

the chamber is rapid and concentration gradients are not significant.

The combined use of analysis of specific toxic products and toxicological

data provides a powerful tool for gaining insights into the toxicity of the

combustion products of a given material.

13
7 . REFERENCES

[1] Birky, M. M. , Hazard characteristics of combustion products in fires:

the state-of-the-art review, Nat. Bur. Stand. (U.S.), NBSIR 77-1234

(1977) .

[2] Potts, W. J. and Lederer, T. S., J. Comb. Toxicology, £, 114-162 (1977).

[3] Q'Mara, M. M. , Combustion of PVC, paper presented at the International

Symposium of Physiological and Toxicological Aspects of Combustion

Products, University of Utah, Salt Lake City, Utah, March 1976.

[4] Paabo, M. , Birky, M. M. and Womble, S. E., J. Comb. Toxicology, £, 99-

108 (1979).

[5] Valentour, J. C., Aggarwal, V. and Sunshine, I., Anal. Chem. , 4£, 924-

925 (1974).

[6] Feldstein, M. and Klendshoj , N. C., J. Lab. Clin. Med., £4, 166-170

(1954) .

[7] Litchfield, J. T. Jr., and Wilcoxon, F., J. Pharmacol, and Exp. Therapeut. 9£, 99-113 (1949) .

[8] Horiuchi, J. and Tanabe, K., J. Research Inst. Catalysis, Hokkaido Univ.

1, 117-131 (1951)

.

(reported in Seidell, A., Solubilities of Inorganic and Metal Organic

Compounds 4th Ed., D. Van Nostrand Co. New York, vol. 1, p. 1106 (1958).

[9] Schneider, C. R. and Freund, H., Anal. Chem., 3£, 69-74 (1962).

[10] Rodkey, F. L. and Robertson, R. F., J. Comb. Toxicology, 6, 44-47

(1979) .

14
Figure

1.

Exposure

chamber
.5

1/min.

ue

(U (0 +J -H U CO >1W Hm

rH

C

<0

m o

•Hw

+j 4J >1 o

rH 3 c o

(« >Ha mo co e -H

«} -P M (0 Cn 3

2^

•OO PO

fa «4H

rM

<up3

*H

fa

16
Figure 3. CO

2 concentrations from 10 mg/1 of Douglas fir

17
18

Figure

4

,

HCl

profiles

in

the

exposure

box
Figure 5. HCN profiles in the exposure box

19
100

pa^BxnuuBo aaa« PfBlUJUV JO 3U3Da8jJ

njeH

c

to

73

(U P

to

f- D

C

C

too

two

co

*H

-u

to -p *Ho

tocu

too

c

VD

(Up

3

CT' •H

CP

20
012345S789 10

CN' m soLunoN, yi/m

Figur<= /. He^d space analysis of HCN

21
T r T 1

1 r

500

400

Wattr

Tkis study

o Heriuchi |8| • Sclmeidm’ |9|

O Rodkey [10|

o Stood, this study

s

300

O

II Vi

200

100

o

o

J I I I I I I L

20 40 60

TEMPERATURE X

80

Fi qii’ smnV>iiit-v of HCN in water

2?
0 10 20 30

MMU1ES OF EXPOSUK

Figure 9. Change in blood cyanide content during

exposure to flaming modacrylic (numbers

in parenthesis refer to average environmental HCN concentration in ppm. Arrows

refer to time of incapacitation. Closed

circles refer to rats)

23
Figure 10. Restrainer for rats

24
0

DOUGLAS FIR- FLAMING

* open circles indica^** animal died during exposure

10

90

80

70

60

I

50-0

z

O

40u

20

10

0

Figure 11. Atmospheric and blood levels of carbon

monoxide at different mass loadings of

Douglas fir decomposed by flaming combustion

25
CO

ppmxlO“2^

Blood

CN'(Mg/ml)

'<=50

Mass Loading (mg/|)

* open circles Indicate animal died during exposure

Figure 12. Atmospheric and blood levels of carbon monoxide and

cyanide at different mass loadings of modacrylic

decomposed by flaming combustion

26

(ludd)

N

DH

•

qHO 3

%
CO

ppm

X

10”^

^

COHb

•

HCN(ppm

Mass Loading ( mg/ I )

* open circles indicate animal died during exposure

Figure 13. Atmospheric and blood levels of carbon monoxide and

cyanide at different mass loadings of modacrylic

decomposed in the non-flaming mode

27

Blood

CN~(fig/ml)
Mass Loading (ntg/i)

A av. cone. /30 min.

* open circles indicate animal died during exposure

Figure 14. Atmospheric and blood levels of carbon monoxide

and cyanide at different mass loadings of wool

decomposed in the flaming mode

28

%

COHb
Inca

pa

citation

WOOL - FLAMING

Figure 15. % incapar Ltation and % death at different mass

loadings of wool in the flaming mode

29
Death,

30

WOOL - NON FLAMING

Fiqure 16. % incapacitation and % death at different mass

loadings of wool in the non-flaming mode

30
NO.

DEATHS

TIME OF DEATH (DAYS)

w-weekend (either day] or day 2)

©-Mass Loading (mg/l)

Figure 17. PTFE - post exposure death

31
DAYS-POST

EXPOSURE

3

<o

NUMBER OF DEATHS

Figure 18. Post exposure mortality from non-flaming

flexible polyurethane foam, (GM-21)

32

HOI
Ord6rs

of

magnitude

more

toxic

33

OOommo c 0

•H e e p O ns (tj M -H x:

iM

m

p

to 4:: 0

•P -P •p u 0 P XI

•a 0) 0 c u P *H (0 a ft

'O e C 0) 0 0 to u H 0

•P ft to to e m P 0u w

0) (U

b TJ 0 0 ^ k. H 6

>P 0 ““ Ma 0 0^5 Cm cn </) — 2 0

o>

•"^50

ana ng ( 0 3 •* ’H Z 0 + 0 e

•H fO « 0 OH rH 0 c

in>,ip u p 1 < n W U C P 0 nj 0 -H 0 .C T) C >p >1 0

4J

g 'O to

k •p cm « U a (0 ,H HU cn n X U -a 3 0 0 Em U 0 0 Eh ft ^ Q k

o>0

(Tl rH TJ3 0)u • •a p c

0) •H 0

Eli E0Mk«

TJk011 <
T3C

O «J P C

in

O u)

(1) -H +) P -P C

fO 0) <N -p e

•Ho

x: (C 0) u D.

(fl

X o cu c

•H tr>

>4-1 oC >P -H o o e H nJ -P P rH

<0 0) >4-1 H ro 3 P C O O -H

40 ip o o c

•H

Oc n 0) cop

<U -PH

ino

(D T) a,

in c 3 cu rP

Ol 40

40 (u e

+J t3 -p

(0 c c Q -P 40

XI

40 Eh

in Pc

(U rP 6

40 -Pm in IT) If)

m ID

p

p ^ Tj< «si< 'a* 'a* ^ O (U EH ChXw

(1) -P

40

4-1 -Po 4n o CM o P 40 Ip Ip Ip Ip 0 Q, Z <0u3H

X!

+J «;)< cn ^ m iP <n

KOX

4-1 in ^ VO

m in ^

IDX4J CM (» in in <T> CM

T5P VO cjv cTi r- in vD

4^

TJ3 m VO CO ^ in CM Ip P

in 00 00 4n ip 00

Ip Ip

p

(U n 3 P o o -H

4-) *P Ip CM cn ^ in VO

inO

04

34

The

order

of

incapacitation

is

independent

of

position

Experimental

variation

noted

was

not

significant

at

th

thep=

0.05

level.
Table 2. Analytical methods for measuring blood cyanide

1. Separation of HCN from blood

- Aeration (5 ml, 30 min.)

- Diffusion flask - Cavette (5 ml, 2 hrs.)

- Microdiffusion cell - Conway (2 ml, 2 hrs.)

2. Measurement of HCN

- Specific ion electrode (0.01 ug/ml)

- Colorimetry - CNCl + pyrazolone/pyridine (0.1 ug/ml)

Benzidine/pyridine

phenylene-diamine/pyridine

- Fluorometry - Mg-quinoline sulfonic acid chelate

(0.5 ug/ml)

- Gas chromatography - ECD - CNCl (0.01 ug/ml)

35
Table 3. Auto-ignition temperatures and temperatures used

in the flaming and non-flaming modes

Material Auto-ignition temp. Non-flaming Flaming

Douglas fir 465“C 440°C 490°C

Modacrylic 725°C 700°C 750°C

Polystyrene GM-51 590°C 565°C 615°C

Polyurethane GM-21 395°C 370°C 420°C

PTFE 620®C 595°C 645°C

Wool 650°C 625°C 675®C
37
Table

4B.

Summary

of

test

method

data

0) a;

4-> -o

IQ o Q o

c< ^

38
Table

5.

Control

blood

values

U-lo

(0

<u3

iH

n) >

TJooH

CQO

+)co

CJ

(0

0)3

t-H>

4-1OQW+ 1 C

•d

0) s

(0

(U +J

(U

0) -P P P ^ ,—,

CJ o

CO

m CO CJC

n (Ti (u a, »» 00 00 00 00 00 C4 0) • 1—

<N CM CM CM CM (0 P

(d ^

—

— <

x: rH

rd

—

CO iH (d •P (0 in o O' 00 (d G 2 C • • • • • • • • O -H

<d 1—(

CO i-H Pfi o «» 00 •H 4h

4-1 > • • O' 0 w + 1 + 1 + 1 2 !Z + 1 + 1 + 1 0 4-1 rH 0 . cr> r' 0 > C ro "Sf CO 'a* o CM O -P •H 0 • • • • • • •H 4H C hq m o rH o X Cd D rH O' CM r- 0 P

Eh

Q

T) ^ 0G

>1 Q) x: 1

•H o o o o o CO iH 00 cm JH 00 00 00 00 00 m cn iH

rH rH rH rH rH rH rH rH rH - o

(d 'W'

W<r 'w" 'W' ''w'

r • P4

'a* rH O' rH CO CO CO s• 4H

na* CM 00 r« CM o o O CQ 0

cn rH rH o o rH o 'a* 00 - G P +1 + 

+ 

+ • + 

+1 + 1 + 

01 0

<U -H

0) to x: 00 o O' O' in TT in inx: -P O' to CQ (0 C" rH CO CO CM O' in 3 3 . 2 -rH K 5 rPh 'a< rH o O' •>a* m E

iH O' iH cn O' ^ 0 O' oo

Cr>

C

•H

X)O oo

1—1 \

tn K

CN oU

O' K

<N o E T3 JQ •H O' •H 0) 3 3 C2 04 +J 4-» <d O 0 XI o Si O' 01 01 P -P 0 p P 1—

0 E 0 >1 01 01 0 0) -H 2

(d 3 O' I-H (U I-H

X 01 0) x: E

CXi 01 o O' Si O' o p

p

C 0

(d E Q >1 0 04 04 •H

g 3 • T3 (U o E X E dP W CQ 01 Oi 0 E K O o 0) iH I—

• • 0 X! XI x: 0) td (d (d 2

I-H rH >i

p 4J

g •H •iH CQ <d <d (1) 3 4-> +J

-P o u S rH P P 0 o s (d (d Eh dP dP dP > 04 04 04

G V)

(d »H

(d

i-H "H

<d J-l o <u H +J O' fd O S

rHo o

•H -H

U) ^ . u <H <. (U . S X: rH

+j0»rH

(U c o

4J -rH >

(0

M

rH

O *

(d TJ CO O CQ T3 2 . <U 2 0 0 • O -P H >0o Td ^ p cu

39

L

reported 
Table

6.

Experimental

temperatures

of

combustion

and

toxicity

results ,—, .—.

in <N • • • • CP CP r- o m f-H

'S' ro • . 'T

m . (U 1 1 in l£> 1 1 C 4J in CP 1 1 lO rH • •H -H • • o in 1 1 • (0 S '—1 n CO • • 1 1 00 00 o CM in 'i* 1 1 ro CM

in o CP

— >—

U n g in CO n <p

'• 1 • • • • l£> n in in o a> n CM

CO o

in CN ,—, o 1—1 .—.

<n • • p' VO

'Cf

M • • o o . • iH 0) CP in iH o 1 1 VO CX) +J CN • . ov p' cn CN + -H 1 1 in VO n 1—1 1 1 • iH in 1 1 o o pH CN

(0 • \ « . o in • • • • o C CP ro VD • « o o pp CN

in

H

g r—i '

w CN CN

U e —• —

— in in

—

in ro «a' P~ pH o • . • • o o • • ro lO o in • • 1—1

in

CN o o cn CN

Xi *

y—^

sp

n VOO y— • . • • CN CN VD VO CN •>» (U CO CN • • CN CN • -P 1 1 ro cn 1 1 (d •p^ 'S' 00 1 1 pH cn O H • . in 00 • • m \ VO VO • • 1 1 CN VD

CJ tP 1—j 1—1

CM CN 1 1 CN iH

M £ — p—

w» 1 1 o cn rM CN cn r-' . • • • • • cn CP ro cn CN a\

CN rH CN iH

0)

Uld

-P

COP — o o o o m in in

625

0)

u CP in o CP 1 04 o 'I' p~ VO in VO o e ^

0)

E-i

in

VO

CP tP <P CP c c c d

pH •H •H •pH g g E e 1—1 •H Cp Cd O CP id tP cd CP cd

(d

p

C pH 'H c P C r-id P

*pH "pH P rH pH P •pH P •rH

p

(0 e 1 e 1 B 1 E 1 <u (d cd c cd c c3 d cd d p rH rH 0 o rH 0 »—1 0 r~i 0

cd CP &4 2 cd Ph 2 U &4 2 iH

b 2 S d b 0 0 0 Eh 0 Q s 04

/•o

determined

by

method

modified

from

Litchfield &

Wilcoxon

[7],

95%

confidence

limits

estimated

from

following

data:

S22.1

mg/1

produced

no

incapacitation

>22.6

mg/1

produced

100%

incapacitation
I1 .

APPENDIX A

PROPOSED TEST METHOD FOR

INTERLABORATORY COMPARISON OF

COMBUSTION PRODUCT TOXICITY

by

Merritt M. Birky
TABLE OF CONTENTS

Page

Test Method Outline iii

1. INTRODUCTION A-1

2. TEST METHODOLOGY A-1

2.1 Animal Model A-2

2.1.1 Test Animals A-2

2.1.2 Incapacitation Model A-2

2.2 Criteria for Test System A-3

2.2.1 Criteria for Animal Exposures A-3

2.2.2 Criteria for Combustion System A-3

2.3 Chamber Design and Construction A-3

2.4 Chemical Measurements (Environmental) A-4

2.5 Biological Measurements A-5

3. DOSE RESPONSE EFFECTS A-5

4. TEST PROCEDURE A-5

4.1 Sample Preparation A-5

4.2 Combustion Conditions . A-6

4.2.1 Non-Flaming Conditions ..... A-6

4.2.2 Flaming Conditions A-6

4 . 3 Exposure Procedure A-6

5. REPORTING OF DATA A-8

6. NUMBER OF EXPERIMENTS AND DATA REDUCTION A-8

7. REFERENCES A-10

Figure la A-11

Figure lb A-12

Figure 2 A-13

ii
Test Method Outline

i| I . Combustion Conditions - Potts Furnace

A. 2 non-f laming conditions

1. 25 ®C below auto ignition temperature

2. 440®C if condition 1 is greater than 460®

! B, 1 Flaming Condition

1. 25®C above auto ignition temperature

|j (a) add 2 drops of ethanol to sample

(b) use ignition spark or hot coil

I II. Sample Conditions

A. Use 1 piece (unless supplied as pellets or granules)

B. Sample conditioning

1. stored for 24 hours at 40 to 50% relative

j hiamidity prior to testing

I 2. stored at 22-24®C

I III. Animal Model

A. Animal Species

I 1. adult rats - 200-300 gm

(a) male only

(b) 6 required per test

(c) suggested strains: Sprague-Dawley , Wistar

I Fisher 344, (specific pathogen free)

B. End Points

1. time to incapacitation (T^)

(a) based on hind leg flexure paradigm

(b) 2 rats removed at T. if uncannulated

(if cannulated they^remain exposed for 30 min.)

2. lethality (LC^q detemination)

(a) 30 minutes plus 14 days post-exposure)

IV. Exposure Conditions

A. 30 minute exposure

B. head only (see chamber)

C. minimum of 3 product concentrations

V. Biological Measurements

A. T.

1. measure COHb, OjHb and total hemoglobin

at T. on 2 animals

B. % lethality as a function of product concentration for

blood chemistry

VI. Environmental Exposure Chamber Measurements

A. CO, CO_ and 0^ continuously or every 5

minutes

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PROPOSED TEST METHOD FOR INTERLABORATORY COMPARISON

OF COMBUSTION PRODUCT TOXICITY

by

Merritt M. Birky

1. INTRODUCTION

The purpose of this test method is to identify those materials that

produce unusually toxic or "super" toxic products when the material is

thermally degraded. The test method is designed to provide toxicity data

in order to classify materials into 2 categories; (1) those producing combustion products of unusual toxicity and (2) those producing combustion products of conventional or moderate toxicity, that is, the toxicity is not

significantly greater than wood (Douglas fir)

Since the apparent relative toxicity of combustion products from different materials will depend on the experimental approach and laboratory

conditions chosen, small differences in measured toxicity cannot be considered

significant in terms of real fire hazard by the present state-of-the-art knowledge in combustion toxicology. Because of these limitations in our present

knowledge and experience, this test method, while generally applicable, is

designed to identify those materials that produce unusually toxic combustion

products as compared to materials such as untreated wood.

The ease with which one can separate the materials into 2 classes will

obviously depend on the definition of unusually or super toxic as compared to

moderately toxic.

It should be recognized that this proposed test method is still under

active study and development. Consequently, it is subject to modification

and change.

2 . TEST METHODOLOGY

The ''selection of a complete system for assessing combustion product

toxicity involves many considerations and alternatives. This test method

reflects the current state of knowledge which should be recognized as being

limited. Any system for assessment of combustion product toxicity must

include; (1) a method of product generation, (2) method of exposing animals

to these products, (3) chemical analytical measurement system and (4) a measurable response or biological end-point in the experiment.

The design of the combustion and exposure system and the biological endpoint will be strongly influenced by the animal species chosen, the number

used in each experiment, and the method of exposure.

The test method includes an animal incapacitation model which should

provide the investigator with increased sensitivity and improved discriminatory power with which to assess relative toxicity. However, since no incapacitation model appears to be adequately developed to place full reliance on it,

lethality and COHb level measurements are used at this time. Such questions,

as the universality of any given incapacitation model to all combustion products have not been adequately explored. For example, some materials will

produce compounds that are primarily sensory and pulmonary irritants, while

combustion products from other materials may have a primary effect on the

central nervous system, or cardiac system, etc. Thus combustion products

from various materials will attack different target organs, and any animal

model should measure the overall ability of the animal to escape or survive

with signficantly increased sensitivity over a lethality measurement.

A-1
since the primary route of entry of toxic combustion products into the

body is by way of the respiratory tract, the designated approach draws on existing knowledge in respiratory or inhalation toxicology. MacFarland (1)

reviewed methodologies in inhalation toxicology, and the approach set forth

below draws heavily on his review.

2.1

2.1.1 Animal Model

Test Animals

Rats were chosen as the animal of choice since a great deal of toxicological data is available. Although similar data are generally available on

mice, the selected blood chemical measurements required in the test necessitate the use of the larger animal with the greater blood supply. The use of

rats does not mean or imply that a correlation has been established between

the effects of fire products on humans and rats.

Male adult rats weighing 200-300 gm are required for the test protocol.

Choices of animal strain are Spraque-Dawley , Wistar or Fisher 344. Specific

pathogen free rats should be ordered. The animals are to be kept for observation 10-14 days prior to use. Clinical examination and pathological evaluation of the test animals are mandatory to verify that they are pathogen free.

Approximately 1 rat in 10 should be used as a control, sacrificed and inspected

for pulmonary pathology. Facilities for housing, care and use of animals must

conform to Federal guidelines (2)

.

The test procedure requires 6 animals per exposure; 2 animals are to be

used to obtain blood samples at time of incapacitation or, if not incapacitated, at the end of the 30 minute exposure. The other 4 are for lethality

determinations

.

2.1.2

Incapacitation Model

In the last few years, 3 animal (rat) incapacitation models have been

developed to study the toxicity of combustion products. The conditioned

avoidance response developed by Packham (3) has been used extensively for

combustion product toxicity and carbon monoxide toxicity studies. A second

system, the rotating activity wheel has been used by Crane et al. (4) to

evaluate combustion products of aircraft cabin materials. A third system,

the rotorod, has been used by Hartung et al. (5) to measure the toxicity of

a variety of materials.

A review of the limited data available from these 3 methods and discussions with these individuals indicate that they give similar results in

terms of toxicity of materials. As each method has both advantages and disadvantages, the choice of one over the other appears to be a matter of personal preference. However, the rotorod and the hind leg flexure are more

amenable to quantification through the triggering of an electrical signal

at the point when the animal can no longer perform the assigned task. The

rotating activity wheel requires visual observation of the animal to determine when the animal can no longer perform the assigned task and with some

materials smoke may obscure this observation.

In a preliminary in-house comparison of the activity wheel and the hind

leg flexure methods, animals exposed to wood, polyurethane or polyvinylchloride combustion products showed nearly equivalent incapacitation times.

Similar comparison of the rotorod incapacitation model has not been done inhouse .The hind leg flexure paradigm was selected for this test method because

of certain advantages or conveniences. At the same time one must realize that

there are also certain limitations to this technique that may not arise in

A2
the other two systems. Future measurements and experience with the various

techniques may suggest that one of these three methods, or a totally different system, may clearly offer a superior test method. However, it may be a number of years before enough data and experience are available to make such

a decision.

2.2 Criteria for Test System

2.2.1 Criteria for Animal Exposures

Exposure period for the test is to be 30 minutes. Heat stress and

oxygen depletion are not to be factors in the test method. In order to

eliminate heat stress, the chamber temperature should not exceed 35°C. The

chamber temperature at the beginning of an exposure shall be 22 i 2°C and

should not rise above 35°C for any time period during the 30 minute exposure.

The environmental oxygen level should not fall below 18%

Heat stress and oxygen depletion are eliminated in order to assess only

the "chemical" toxicity of products produced during thermal degradation.

These 2 factors, if included, would affect the chemical toxicity significantly, and an exploration of the infinite variations possible would delay

a test method for years. For this reason these two parameters are to be

controlled within the narrow limits specified.

2.2.2 Criteria for Combustion System

Certain minimal requirements are also placed on the method of product

generation. It is clear that the 2 distinct modes of combustion (flaming

and non-flaming) should be realizable and each mode controlled and explored

separately for toxicity. In addition, the heat source (furnace system) must

be temperature or heat flux controlled over a broad range. Due to the fact

that the exposure is relatively short, the shape of the concentration-time

curve becomes important. That is, the concentration of combustion products

should peak rapidly and ideally remain constant for most of the exposure

period. This means that the combustion products should be generated rapidly

and the atmosphere within the chamber equilibrate rapidly. This will

obviously depend on the thermal response of the material.

2 . 3 Chamber Design and Construction

Various factors, which influence the chamber design, have to be considered before the chamber can be constructed. These factors are whether

the animals are placed in:

(1) a static or dynamic atmospheric exposure and

(2) a head only or whole body exposure mode.

These factors will influence the restrictions on environmental temperature rise in the chamber.

In the static mode, the products are generated in the animal chamber,

whereas in the dynamic mode, the products can be generated exterior to

the animal chamber and transferred by a blower or compressed air. Each

has advantages and disadvantages. In this particular protocol, the static

mode was chosen since certain toxic products may be lost by adsorption during

transfer in a dynamic system. This mode also requires less material for

toxicological evaluations.

Head only exposure was considered advantageous for it minimizes the

possibility of heat stress and it allows the investigator to monitor various

physiological functions. Head only also minimizes the deposition of toxicants

on the animal's fur and the subsequent ingestion of these toxicants by the

animals while grooming. On the other hand, whole body exposure, in which

Athe animals are required to exercise moderately during the test, is advantageous for observation of behavioral changes during the exposure. Whole

body exposure also eliminates the stress on the animal caused by the restraint

required in the head only technique. After due consideration of all these

factors, the head only exposure technique was selected.

The chamber design is shown in Figures la and lb and is to be constructed

of polymethvlmethacrylate sheet. The inside dimensions are 48 inches long

18 inches high by 14 inches deep. The nominal volume of the chamber is 200

liters. The chamber should be gas tight and checked for major leaks and any

leaks corrected. A pressure relief balloon is to be attached to allow for

expansion of the gases during combustion of the sample. In addition, a blow-out panel should be incorporated in the chamber. This panel should be

a flexible film, such as mylar or teflon coated aluminvim foil.

In the chamber shown in Figure la and lb, 6 animals are exposed head only

in individual restrainers. Behavioral incapacitation measurements are performed on all 6 animals. Two of the 6 animals must be sacrificed for blood

chemistry (COHb) at the time of incapacitation. Alternatively, if two animals

are cannulated prior to exposure, then the blood COHb determinations can be

determined at the time of incapacitation without sacrificing the animals.

In this case, all 6 animals may be exposed for the full 30 minutes.

The combustion module shown in Figure 2 is fitted into the animal chamber

as shown in Figure 1. The degradation system is similar to that reported by

Potts and Lederer ( 6 ) and consists of a small furnace closed at the bottom

end. The furnace temperature is controlled with an automatic temperature

controller. The temperature is monitored with a thermocouple inside the

sample container.

2.4 Chemical Measurements ( Environmental ) The environmental temperature of the chamber must be recorded continuously

or every 5 minutes during the 30 minute exposure to insure that it does not

exceed 35°C. The temperature sensor must be placed in the air at the level

of the animals. A chrome 1-alumel thermocouple is recommended for this and

has a sensitivity of approximately 40 uv/deg. Celsius.

Continuous measurements for 02r CO2 and CO are to be made and recorded.

Alternatively, if a gas chromatographic technique is used, measurements of

*^2' *^^2 made every 3 to 5 minutes. The oxygen level in the

chamber shall not fall below 18% any time during the exposure. Oxygen is to

be supplied to the chamber to maintain the level between 18-21%.

Continuous monitoring of 82 ^ CO

2 and CO will remove some of the products

from the chamber. For example, approximately 0.5 liter/min. flow rate is

required for non-dispersive IR analysis of CO and CO

2 and analysis of 02 « During a 30 minute exposure this amounts to 15 liters that must be pumped

back into the chamber. Oxygen or air should be added depending on the degree

of O

2 depletion. One must correct for this addition when calculating the

mass loading of combustion products.

The overall "concentration" of combustion products is based on mass loading of the sample into the furnace divided by the volume of the exposure chamber

and is expressed in milligrams per liter or grams per cubic meter. It is this mass loading that is used to calculate the LCcq/ i.e. the mass loading that

results in the death of 1/2 of the animal population. Equivalently, the EC^q

is the mass loading (mg/1) that incapacitates 50% of the animal population in

the 30 minute exposure period.

Measurement of other expected toxicants is optional. For example, HCl

can be measured when vjn'-l materials are being examined. Likewise, HCN can

A-4
be measured as desired when nitrogen containing materials are thermally

degraded.

2.5 Biological Measurements

During the exposure period, observations of the animal behavior should

be noted and recorded. Time to loss of avoidance should be recorded. Any

unusual behavioral activity should also be recorded along with the time.

Selected blood chemical measurements are required and measurement of

other biochemical parameters is suggested. Measurements of COHb, O-^Hb and

total Hb on at least 1 and preferably 2 animals at the time of incapacitation are required . If 2 of the 6 animals are not cannulated, 2 are to be

removed at the time of incapacitation and blood samples obtained as rapidly

as possible. The remaining 4 animals are to be exposed for the full 30

minutes unless they all die before the 30 minutes

It is suggested that blood cyanide measurements be made when nitrogen

containing polymers are being studied. This, however, is not required.

3. DOSE RESPONSE EFFECTS

Two end-points are to be obtained in the test procedure:

( 1 ) incapacitation and

( 2 ) death

Both of these experiments are to be determined as a function of the mass

loading of combustion products. It is anticipated that both endpoints can be

obtained during the same experiment although this is not always possible.

That is, the time to incapacitation is recorded during the 30 minute exposure

period, and the exposure is continued for the full 30 minutes even though

the incapacitation occurred earlier.

The lethality endpoint is evaluated as a function of the mass loading

in order to construct a dose-response curve from which the LC^q may be

estimated. The ECcq may also be estimated by constructing a curve of the

concentration versus percent-of-population-incapacitated in 30 minutes. The

actual LCgQ and EC 5 Q

with their 95% confidence limits should be obtained via

an appropriate published statistical method, such as that of Litchfield and

Wilcoxon (7). In some cases, depending on the particular toxic products,

incapacitation may not occur during the exposure period, but death may occur

during the 14 days post exposure period. In these cases, it may not be

possible to obtain an EC^q for that material.

The data for the lethality determination must include the deaths during

the 30 minute exposure period and the 14 day post-exposure period.

Since an incapacitation model is used, a measurement of the time to

incapacitation should be recorded, although the use of time to an effect is

still open to discussion. The number of animals that die during the exposure

and during the 14 days post-exposure period must be recorded.

4. TEST PROCEDURE

4.1 Sample Preparation

Material samples to be evaluated for toxicity should be conditioned in

a constant humidity chamber maintained at 40 to 50% relative humidity at a room temperature of 22-24°C for a period of 48 hours prior to testing. The

sample specimen is to be tested in one piece.

A4.2 Combustion Conditions

The toxicity of combustion products from any material is to be determined

separately for non-flaming or smoldering combustion and for flaming combustion.

4.2.1 Non-Flaming Conditions

Each material is to be evaluated at 2 non-flaming temperatures: (1) 25°C

below auto-ignition temperature with a maximum temperature of 800 °C and

(2) 440°C, if 25®C below auto-ignition temperature is above 440°C by 50®C or more. The 440°C temperature is 25°C below the auto-ignition temperature of

Douglas fir. The auto-ignition temperature will be different for each

material and this temperature is to be established without animals as described below.

First, the temperature of the furnace is set at 500°C and when this

temperature is attained, the material is introduced into the furnace. Sample

size should be the maximiam that one anticipates using for toxicity tests since

a larger size may ignite at a lower temperature. Do not exceed 35 mg/1 of

mass loading (for 200 liter chamber this is a 7 gm sample) to reduce risk of

creating an explosive mixture. If auto-ignition does not occur, the process

is repeated at 550 °C and so forth until the auto-ignition temperature is

bracketed within 25°C of the auto-ignition temperature. 800°C is the upper

temperature at which the toxicity is to be studied regardless of whether

auto-ignition occurs or not. If auto-ignition does occur at 500°C, the furnace temperature should be decreased in increments until the auto-ignition

temperature is bracketed within 25°C.

Once the auto-ignition temperature of the material has been established,

the furnace temperature is to be decreased by 25°C for the non-flaming condition. In other words, if a material auto-ignites at 450°C, the maximum

temperature at which this material is studied in the non-flaming mode of

decomposition is 425°C. The auto-ignition temperature may be sample size

dependent, so that once this auto-ignition temperature is established with a given sample size, it should be checked without animals when the size is

changed. However, for a given material only one temperature is used.

As a point of reference, Douglas fir has an auto-ignition temperature,

established by the above procedure, of approximately 465°C.

4.2.2 Flaming Conditions

The material must also be elevated under flaming conditions. The flaming

mode of decomposition is to be carried out at a furnace temperature 25°C

above the auto-ignition temperature established in the previous section.

The 25°C increase in temperature is to insure ignition. In addition, 2-3

drops of ethanol is to be added to the sample and an electric spark should

be used to insure early ignition of the test material. It should also be

noted that the maximum furnace temperature for flaming studies is 800°C.

4 . 3 Exposure Procedure

Prior to experiments involving animal exposures , the system should be

checked out to determine that the analytical and combustion systems are all

operating correctly. The analytical instrumentation for O 2

, CO

2 and CO

should be calibrated with a known gas mixture containing the 3 gases. A

regular calibration schedule of this instrumentation must be made. The O

2 can be checked with air.

To check the combustion system, the material to be tested for toxicity,

including the reference material, should be used in the system before animals

rp invol.ved. This check-out procedure is to determine:

A6
(1) the degree of oxygen depletion during coinbustion

of the sample,

(2) the increase in temperature in the chamber during

sample degradation and

(3) that the proper conditions have been established

for carrying out either non-flaming or flaming

combustion exclusively.

Once these conditions have been established, an experiment involving

animals can be initiated.

The instrumentation for CO

2 and CO measurements are zeroed and a base

line established during the checkout procedure. Oxygen concentration is also

recorded prior to initiation of the exposure.

The furnace temperature is established and the system allowed to reach

equilibrium 10 minutes before the start of the experiment. During this warmup period and the recording of pre-exposure data, the door of the exposure

chamber is left open.

After these conditions are established, the animals are placed in their

respective positions. To initiate the experiment, the weighed sample is

placed in the furnace, and the door of the chamber is immediately closed.

Placement of the sample into the furnace designates the starting time of

the exposure

If temperature rise in the exposure chamber is a problem, the electrical

power to the furnace may be cut off when the sample is completely degraded

(3-5 minutes). The length of time required to degrade the sample can be

determined by watching the increase of CO or CO^ concentrations. When these

concentrations reach a steady state, the heater"^can be shut off.

If no animals are cannulated, two animals are to be removed at the time

of incapacitation and the time recorded. Blood samples are to be obtained

from these 2 animals as rapidly as possible. The remaining 4 animals are to

be exposed for the full 30 minutes. If 2 animals are cannulated, the blood

can be obtained at the time of incapacitation. These 2 animals should continue

to be exposed for the full 30 minutes. If no incapacitation occurs, the

exposure is to be terminated at 30 minutes

The pathological examination on any animals that die during the exposure

or are sacrificed immediately after the termination of the exposure should

focus on the condition of the respiratory tract. Visual observations of soot

deposits, pulmonary edema, hemorrhagic lungs, etc., should be recorded.

Clinical examination of post-exposure behavior of animals not killed

during the exposure can be made, however this is optional. This examination,

immediately after exposure, should include the following behavioral parameters: (1) exploratory behavior, (2) righting reflex, (3) pain reflex,

(4)

nuzzle reflex, (5) posture, (6) eye irritation, (7) nasal discharge,

(8) respiratory irregularities (gasping, wheezing, etc.) (Irwin [8]). Any

other unusual behavior patterns must be recorded.

The animals are to be kept for a period of 14 days post-exposure. Any

deaths during this time period should be included in the lethality calculations. In addition, during these 14 days any unusual behavior should be

noted and recorded including daily animal weights

A5. REPORTING OF DATA

Required exposure chamber measurements are:

(1) carbon monoxide concentrations,

(2) carbon dioxide concentrations,

(3) oxygen concentrations, and

(4) temperature in the vicinity of the

nose of the rats

.

The above measurements are to be recorded at a minimum of 5 minute

increments during the exposure.

The temperature at which the sample is thermally degraded must also be

recorded.

Required biological measurements are:

(1) carboxyhemoglobin at time of incapacitation on

2 rats

,

(2) total hemoglobin at time of incapacitation on

2 rats

,

(3) oxyhemoglobin at time of incapacitation on 2 rats,

(4) time to incapacitation on all 6 rats, if incapacitation occurs , and

(5) mortality data during the exposure period and for the

14 day post-exposure period.

The blood chemistry measurements are to be done at the time of incapacitation or, if incapacitation does not occur, immediately after the 30 minute

exposure

.

In addition to the above required data, other observations can be made

and recorded during and after exposure. For example, observations on animal

posture, righting reflex, exploratory behavior, respiratory function (gasping,

wheezing) , grooming and eye and nasal discharge and body weight change should

be recorded. This information will be useful in evaluating the extent of

the toxicological insult.

6. NUMBER OF EXPERIMENTS AND DATA REDUCTION

As noted above, 6 animals are. to be exposed per experiment. Dose

response data based on lethality is to be obtained on each of 3 thermal

degradation conditions. A minimum of 3 concentrations are required for

each of these thermal conditions. The 3 thermal conditions are:

2 non-flaming conditions -

(1) 25 °C below auto ignition temperature and

(2) at 440°C if condition (1) above is 490°C or greater

1 flaming condition -

(3) 25°C above auto ignition temperature

The minimum number of animals required to evaluate a given material is as follows:

3 (thermal conditions) x 6 (animals/exp. ) x 3 (concentrations minimum)

= 54 animals.

A8
It is unlikely that one can get a statistically valid LC^q based on 3 concentrations unless one can get about a 20%, 50% and 80% response on these

3 concentrations, so that it may require significantly more animals per

material. The number of animals will also depend on the number of temperatures required to complete the evaluation.

Time to incapacitation, blood carboxyhemoglobin and the mortality data

for each exposure should be recorded. The percent mortality for each concentration for a given thermal condition should be plotted, i.e., % mortality

should be plotted against mass loading of combustion products so that an LC^q can be estimated from the plot. This percent mortality must include all

mortalities that occur during the exposure and the 14 day post exposure

period.
7. REFERENCES

[1] MacFarland, H. N., "Respiratory Toxicology," Chapter 5 from Essays

in Toxicology. Edited by W. Hayes, Jr,, Acad. Press 1977.

[2] Guide for the Care and Use of Laboratory Animals, DHEW Publications

No. (NIH) 74-23 (1974).

[3] Packham, S. C., "Behavior and Physiology: Tools for the Assessment of

Relative Toxicity," Paper presented at 17th National Cellular Plastics

Conference on Safety and Product Liability, Washington, D.C. (Nov. 18-

20, 1974)

.

[4] Crane, Charles R. , Sanders, Donald C., Endecott, Boyd, R. , Abbott, John

K., Smith, Paul W. , "Inhalation Toxicology: I - Design of a Small Animal

Test System, II - Determination of the Relative Toxic Hazards of 75

Aircraft Cabin Materials," FAA-AM-77-9, March 1977.

[5] Hartung, R. , Ball, G. L. , Boettner, E, A., Rosenbavim, R. , Hollingsworth,

Z. R. , "Evaluation of the Performance of Rats Exposed to Combustion

Products of Polyurethane Foams and Wood on a Roto Rod." To be published

in November issue of Journal of Combustion Toxicity, 1977.

[6] Potts, W. J. and Lederer, T. S., "A Method for Comparative Testing of

Smoke Toxicity," Journal of Combustion Toxicity, Vol. 4, pp. 114-162

(May 1977)

.

[7] Litchfield, J. T. , Jr. and Wilcoxon, F., "A Simplified Method of Evaluating Dose-Effect Experiments," J. Pharmacol, and Exp. Therapeut. 96 , 99-113 (1949) .

[8] Irwin, S., Psychopharmacologia. Vol. 13, pp. 222-257, 1971.

A-10
A-11

Figure

la.

Exposure

chamber
CHAMBER

CONSTRUCTION

MATERIAL:

0.50

POLYMETHYL

METHACRYLATE c/>

A-12

FURNACE

ENCLOSURE
PYROLYSIS/COMBUSTION FURNACE

Figure 2. Cutaway drawing of the pyrolysis/combustion furnace.

A-13
NBS-II4A (REV. 9-781

U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBSIR 80-2077

3. No.

4. TITLE AND SUBTITLE

Development of Recommended Test Method for Toxicological

Assessment of Inhaled Combustion Products

5. Publication Date September 1980

7, AUTHOR(S) Merritt M. Birky, Maya Paabo, Barbara C. Levin,

Susan E. Womble, Dolores Malek

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, DC 20234

8. Performing Organ. Report No.

11. Contract/Grant No.

O^^^CIIZATION NAME AND COMPLETE ADDRESS fSfreef. City, stM^. ZIP)

Products Research Committee (PRC)

c/o Dr. John Lyons

National Bureau of Standards

Washington, D.C. 20234

13. Type of Report & Period Covered Final

15. SUPPLEMENTARY NOTES

r 1 Document describes a computer program; SF-185, FIPS Software Summary, is attached.

16. ABSTRACT (A 200-word or less /actual summary ol most si^nificont information. If document incJudes a si^ificant bibliogr^hy or

literature survey, mention it here,) Tll6 Obj6CtiV6 Of tll6 prOj 6Ct SUppOlTtBd by PRC WSS tO QGVGlOp

a test method for measuring the toxicity of combustion products from polymeric

materials including cellular plastics. The development of such a test procedure

was considered an essential first step to determine the hazard to life when cellular

plastics are involved in fire.

As a result of this work, a test procedure was developed. It consists of 3 major

elements; (1) combustion system, (2) chemical analysis system and (3) animal exposure

system. Two biological endpoints obtained from the exposure are: (1) incapacitation

in 30 minute exposure period, and (2) lethality in 30 minutes plus 14 days post exposure

The test apparatus has been evaluated to determine mixing rates and loss of reactive

chemicals in the exposure chamber. In addition, a statistical evaluation of the

experimental results demonstrated that order of incapacitation was independent of

animal location.

Evaluation of a limited number of different materials that produce different toxicolog:

cal syndromes has demonstrated the utility of all 3 endpoints. Two natural polymers

(wood and wool) and 2 synthetic materials (modacrylic and PTFE) have been studied

in detail. In addition, preliminary data have been obtained on a flexible polyurethane

17. KEY WORDS (aix to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper napne; separated by semicolons) Combustionj fatality (LC^q) ; hydi'ogen cyanide; incapacitation;

inhalation; test method; toxicology.

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