conditions. For only one of the pairs of test parameters is the di
between new and used oil statistically significant. In the 400°C #1
mode, the difference in Ct-product is significant at the p=0.05 level
(Student t-test, 2-cailed). Even here, however, the times-to-death are not
significantly di:ferent. We conclude, therefore, that used cil dees not
contain or produce TDP's that are significantly different from those
generated by new oil either a qualitative or a quantitative sense.

The results of comparisons made between Exxon 2380 and some related
contemporary products are in Table 4. Each material was tested at 400°C,
under flaming and nonflaming conditions. It is apparent that there are
some significant differences in rat response times and in CO production,
both among the different materials and between the flaming/nonflaming nodes
for some of the individual materials. At the p=0.05 level (Student test,
2-tailed), the tj's are different (flaming vs. nonflaming) for all materials
except the Quaker State Oil. Conversely, only for Quaker State oil are the
two tg's different. The Ct-products for both incepacitatior and death are
not significantly different when flaming is compared with nonflaming mode.
The aviation hydraulic fluid, Skydrol 500B, does not decompose appreciably
at 400°C unless it is flaming (400°C is obviously below its autoignition
temperature); this explains the lack of response in the 400°C nonflaming
test.

When the response times listed in Table 4 are arranged in the order
of increasing ty, it is easier to compare the relative potential toxici
Table 5 presents the seven materials in the order of decreasi toxicity (as
implied by increasing magnitude of t;) for flaming and nonileming modes.

This table also presents the "worst-case" rank order, in which a material's
position is determined by using the t; that 1s the shorter of the two
obtained from flaming and nonflaming tests.

When ranked by t; in the 400°C nonflaming mode, it is interesting that

the four aviation products are the four ieast-toxic materials. The 400°C
flaming data, when compared to nonflaming, illustrate a common phenomenen
in combustion toxicology: the rank-orders for the same set of materiais in
the two modes are quite different. The least-toxic, nonflaming, beccmes
the most-toxic material under flaming conditions. Also, the two materials
that are now least toxic, in the flaming mode, are the two that are, or are
derived from, natural petroleum products; the others are all synthetics.

The most important distinction between the flaming/nonflaming
orders is the fact that the position of Skydrol changed from least toxic
(nonflaming) to most toxic (flaming). This complete turnabout has not been
an unusual occurrence in the 10-year period that this laboratory has been
testing materials, and it serves to emphasize the potential foily of select-
ing and/or specifying a single thermal environment at which all materials
would be evaluated.

Our philosophy that has emerged from our testing experience is
ideally, materials should be evaluated for toxicity over the range o
thermal environments that they might reasonably encounter in a “real

te


Aliquots of compressor bleed air were collected by several sampling
techniques end subjected to chemical analysis in three different partici-
pating laboratories. Additional online analyses were conducted at the
site. The results of all these tests are to be xublished by the NTSB (3).

The online analytical chemica) results from the bleed air analyses
did not support the hypothesis that harmful concentrations of carbon
monoxide (CO), carbon dioxide, or oxides of nitrogen were present. Analysis
of the batch samples, using a gas chromatograph/mass spectrometer, revealed
the presence of a number of identifiable gases, but these were reported to
be present in such low concentrations that they probably would not alter a
pilot's perception or behavior. However, the presence of an unidentified
substance of exceptional toxicity (e.g., more toxic than CO) emanating from
the engine could not be ruied out.

Furthermore, these NTSB-sponsored tests showed that when oil was
injected directly into the engine air intake it appeared as a mist in the
bleed-air line, but this mist was removed by glass wool filters ahead of
the sampling/analytical devices. It was possible, therefore, that with an
unfiltered line a significant toxicity could be associated with breathing
the oil mist.

INTRODUCTION

Any attempt to assess the combined toxicity of a mixture of unknown
chemical compounds by doing only a chemical analysis is an open invitation
for utter frustration. Only those compounds for which the selected analysis
is appropriate will be quantitated and, even though several potentially toxic
species are measured, it is at present almost impossible to predict the
combined toxic expression of such a mixture.

It was principally for these reasons that we decided to use experimental
animals to investigate the toxicity of acute exposures to the thermal deconm-
position products (TDP) of Exxon 2380 and other lubricants, as well as the
toxicity associated with inhalation of oil aerosols. The foundation and
basic techaiques for such inhalation toxicology assays are well established
and have been in continual use in our laboratory for the past 10 years. With
this technique, the exposed animal serves as both the "analyzer" and the
“integrator,” assuring that each toxic species, known and unknown, will not
only be accounted for but will be assigned its proper weighting factor in
summing the total effective toxicity of the mixture.

Two types of animal experiments were designed and carried out in the
Aviation Toxicology laboratories of the Civil Aeromedical Institute in
Oklahoma City, Oklahoma.

The first set of experiments would expose rats to the TDP from
synthetic and petroleum-based lubricants and from one fire-resistant
hydraulic fluid used in aircraft systems. The TDP would be generated at
specific temperatures over the range 300°C to 600°C and include both
flaming and nenflaming decomposition. Measured physiological endpoints
would be time-to-death (tg) and time-to-incapacitation (c;)-



he -

component that is significantly more toxic to the rat than is the quantity
of carbon monoxide produced. Therefore, it is unlikely that any
contaminant originating from lubricant decomposition in the en;
be more toxic than the CO content--which, in the Garrett/NTS3 tests, was
reported to be insignificant.



chamber was closed and the recirculation and combustion equipment attached.
The air pump, which circulated chamber atmosphere through the gas chromato~
graph's sample loop, was activated and the chamber mixing blower and fan
turned on. A 3-mL sample of the fluid to be tested was pipetted into the
quartz combustion boat. For flaming combustion experiments, the hot-wire
igniter was turned on; for nonflaming experiments, the igniter was removed
from the assembly. Simultaneously, the sample was pushed into the heated
area of the combustion tube, cage rotation was begun, the system sealed,
and the recirculation blower and sampling timer were activated.

The chamber atmosphere was sampled and analyzed for 09 and CO at 1.88-min
intervals, beginning 1 min after insertion of the sample. Rats were observed
until they could no longer perform the coordinated act of walking in the
rotating cage and began to tumble; cage rotation was then stopped and tq
was recorded. The tg was recorded wher visible signs oi breathing ceased.
Oxygen was replenished to ambient levels when necessary, as indicated by
the gas chromatographic analysis. The exposure time was 30 min except in a
few experiments where the CO concentrations were very low; in these cases
exposure time was extended in order to determine a reaction time. Any surviv—
ing animals were held for observation for a minimum of 14 days.

Aerosols. Rats were weighed and placed in the individual head-only
holders; these were then fitted into the bushings on the side of the 205-L
chamber so that the rats' heads protruded into the chamber interior.

Chickens, for head-only exposures, were placed in the plastic beakers
and secured by the rubber seal and restraining collar. For waole-body
exposures, chickens were simply placed in the chamber and allowed to move
about freely.

With the experimental animals in place, the test material was added to the
atomizer and the entire assembly weighed to the nearest 0.01 g. (Samples of
used oil were first filtered through "Shark Skin" filter paper (Arthur H.
Thomas Co., Philadelphia, Pennsylvania) to prevent clogging the atomizer.)

The atomizer was clamped in position and connected to a tank of compressed
air through a pressure regulator and a flowmeter. The regulator was used to
control the airflow to the atomizer at a constant 32 cfm (15.1 L/s) through-
out the 7-hour exposure period. Timing began when the airflow started.

At the end of the exnosure, airflow was stopped, animals were removed
and held for observation, and the atomizer assembly was reweighed to determine
the quantity of fluid used.

RESULTS AND DISCUSSION

The thermal stability of the product of primary interest, Exxon 2380
(B193}, was evaluated in a preliminary experiment with no animal exposure.
A small sample was placed in the furnace boat of the combustion assembly
and the furnace temperature raised slowly. Traces of condensation first
appeared downstream at 208°C; measurable CO occurred at 306°C along with
a dramatic increase in smoke density; CO evolution then increased rapidly,


Table 1. Test Materials

Material Density Wt of 3-mL
(g/mL) Sample (g)
Exxon Turbo Oil 2380 (B193) 0.9512 2.8536
Exxon Turbo Oil 2380 (B227) 0.9462 2.8386
Exxon Turbo Oil 2380 (B245), Used 0.9456 2.8368
Exxon Turbo Oil 2389 (B64) 0.9208 2.7624
Mobil Ii Jet Oil 0.9676 2.9628
Mobil I Synthetic Mctor Oil 0.85C1L 2.5503
Quaker State 10W-40 HD Motor Oil 0.8536 2.5608
Skydrol 500B Fire-Resistart
Hydraulic Fluid 1.0372 3.1116
Paraffin Oil* 0.8404 2.5212

*Fisher Scientific Company, Fair Lawn, New Jersey.



The measuremeat af CO productian thraughaut the exposure periad would
give an estimate of the total toxic dose due to CO. Our experience with CO
studies in rats should allow a reliable judgment of whether or not a
component is produced that contributes more to the total toxicity than does
co.

A second set of experiments would involve a 7-hour exposure of both
rats and chickens to aerosols of one synthetic lubricant and of a chemical
gtade of light paraffin oil. These animals would be kept for a minimum of
3S days gostenposure and be observed daily for any signs of tonicity.

MATERIALS AND METHODS

Test Animals. Male rats (Sprague-Dawley derived) were obtained from
Charles River Breeding Laboratories, Wilmington, Massachusetts; their size
was 1060 to 120 g when acquired. All animals were held in isolation for 8
days, and, as an added precaution, maintained during the first 4 days on
drinking water that contained 1.5 g sulfathiazole per liter. After the
B-day petiod they were moved from isolation into regular quarters. Ail
animals to be used on a given day were fasted overnight; each was weighed
just prior to exposure.

Test Materials. A total of nine materials was utilized in the testing
program. Six of these were synthetic lubricating oils, one was a petroleun-
based lubricating oil, one a synthetic hydraulic fluid, and the last was a
refined paraffin oil. These materials and their specific gravities are in
Table 1.

Four of the synthetic lubricants were products of Exxon Company, Houston,
Texas. Three of these were different batch numbers of the same turbine oil
product, identified as Exxon 2380. Test specimens of batch numbers B193 and
B227 were en from freshly-opened Il-quart cans of Exxon 2380. The test
specimen, Exxon 2380 (batch 245), was oil that had been used in an operating
turboprop aircraft for 165 hours. The fourth test specimen was taken from
a freshly-opened i-quart can of Exxon 2389 (batch 64); this particular formula-
tion is used in some aircraft in the Federal Aviation Administration (FAA) fleet.

Two synthetic lubricants were products of Mobil Oil Corporation, New
York, New York. Mobil II Jet Oil is a product also used in some FAA turbo-
prop aircraft. The second product, Mobil I, is a synthetic oil formulated for
use in automobile piston engines. An additional automobile motor oil, Quaker
State 10W-4OHD (Quaker State Oil Refining Corporation, Oil City, Pennsylvania),
was tested for comparison of a petroleum-based oil with the synthetic Mobil I
product. All three test specimens were taken from freshly opened l-quart cans.

On previous occasions, ané in connection with other aircraft accidents
unrelated to any potential bleed~air problem, the question of toxicity of TDP
from hydraulic fluid had arisen. Therefore, we took this opportunity to
evaluate also a sample of synthetic hydraulic fluid that is reported to
exhibit improved thermal stability properties. The test specimen was Skydrol
500B Fire-Resistant Hydraulic Fluid (Monsanto Company, St. Louis, Missouri)
and came from a previousiy-unopened i-quart can.



REFERENCES

San Francisco Examiner, Sunday, June 14, 1981.

Oklahoma City Times, "Fumes from Engine Cause Plane Crashes?",
Monday, June 15, 1981.

Wizniak, E. P.: Special Investigation~-An Evaluation of the
Potential for Turbine Jil Byproduct Contamination of an
Aircraft Cabin Environmental System. National Transportation
Safety Board (publication pending, 1983).

Crane, C. R., D. C. Sanders, B. R. Endecott, J. K. Abbott, and
P. W. Smith: Inhalation Toxicology: I. Design of a Smali-Animal
Test System, II. Determination of the Relative Toxic Hazards of
75 Aircraft Cabin Materials. Federal Aviation Administration
Report No. FAA-AM-77-9, 1977.

Crane, C. R., D. C. Sanders, B. R. Endecott, J. K. Abbott:
Electrical insulation Fire Characteristics, Yol. 11, Toxicity.
Urban Mass Transportation Administration Report

No. UMTA-MA-06-0025-79, II, 1978.

16



Internal dimensions of the pclymethylmethacrylate (PMMA) chamber
were 25.4 cm long, 22 cm wide and 22 cm high; the three-compartment rotating
cage was 20 cm in diameter and 21.4 cm long. The quartz (Vycor) combustion
tube consisted of a section 5 cm in diameter, 33 cm long, connected to an
8 cm long, 2.5 cm in diameter section by a 6.4 cm taper segment. The total
enclosed volume for the chamber, combustion tube, and recirculation assembly
was 12.6 L.

Heat was applied to the oil sample with two semicylindrical heating
elements encircling the 5 cm diameter section of the combustion tube. A
chromel-alumel thermocouple embedded in the lower element was calibrated
against a similar thermocouple in the sample combustion boat to provide a
reference temperature for sample thermal control. Liquid test samples were
contained in semicylindrical quartz combustion boats with closed ends, 7.5 cm
long x 4 cm wide. Ignition of gases evolved from the heated oil samples was
accomplished, when desired, with 1 hot-wire igniter consisting of two loose
coils oi resistance wire suspended between heavy stainless steel wires : -at
extended down the tube to a point slightly downstream from the combustion
boat. Current was applied to the igniter from a 12 volt wet cell battery
from the time ot sample insertion until gases from the sample ignited.

Aerosol Exposure Assembly. All aerosol exposures were performed in a
PMMA chamber with inside dimensions 75 cm long x 61 cm wide and 45 cm high,
and ar internal volume of approximately 205 L. Bushings were instalied along
one side to accept three rat holders for head-only exposures. Each holder
was constructed from a 21 cm length of 6.5 cm diameter PMMA tubing equipped
with leg holes, an adjustable sliding plug, and a plastic restraining collar;
the end of the holder that protruded into the chamber was fitted with a rubber
seal encircling the rat's neck and preventing any body exposure to gas or
aerosol. An end face of the chamber contained two openings, 8.9 cm in diam-
eter, in diametric corners. Aerosols were produced by flowing compressed air
through a 250-mL glass atomizer containing the test liquid. The atomizer
was positioned at the top corner opening and the lower opening was fitted with
a plastic tube that terminated in a fume hood; this arrangement allowed a
flow-through type of atmosphcre generation. Chamber mixing fans were not used
in this study to avoid excessive contact of the aerosol with the walls of the
chamber.

Head-only chicken exposures required a different restraining system due
to the different body configuration. Each animal was placed in a container
made from a 400-mL disposable plastic beaker trimmed to the 340-mL line; a
sheet of thin rubber (dental dam material) with a 1.9 em hole in the center
was placed over its head and secured to the beaker with a large rubber band.
Then a second X-shaped collar of 2 mm thick gum rubber with a 2.5 cm hole in
the center was fitted over the chick's head, folded over the sides of the
beaker, and taped in place. The dentai dam provided a soft but airtight seal
around the bird's neck and the heavier rubber collar prevented escape.

Animal Exposure Procedures

Combustion Products. Sequentially, the exposure procedure consisted
of bringing the furnace to the desired temperature, weighing the rats, and
placing them in the individual compartments of the rotating cage. The


FAA-AM-8 3-12

INHALATION TOXICOLOGY: ILI. EVALUATION OF THERMAL
DEGRADATION PRODUCTS FROM AIRCRAFT AND AUTOMOBILE
ENGINE OILS, AIRCRAFT HYDRAULIC FLUID, AND MINERAL OIL

Charles R. Crane
Donald C. Sanders
Boyd R. Endecott

John K. Abbett

NALD ZAL

Civil Aeromedical Institute
Federal Aviation Administration
Oklahoma City, Oklahoma

is”

APRIL 1983

Document is available to the public through the
National Technical Information Service
Springfield, Virginia 22161

Prepared for 7
U.S. DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
Office of Aviation Medicine <
Washington, D.C. 20591 Se

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producing a chamber concentration of 5,000 ppm at 344°C. By 350°C most of
the sample was reduced to a solid char that continued to evolve CO until
a chamber concentration of 10,600 ppm CO was attained at a furnace
temperature of 533°C.

This preliminary experiment established 300°C as a suitable lower limit
for the next series of tests.

Thermal Decomposition/Animal Exposure Tests

Exxon 2380 decomposition at a selected set of nonflaming isothermal
conditions gave the results in Table 2. At 300°C the amount of CO produced
was guite low and there was no visible effect on the animals during the
30-min exyvosure. At 350°C, the first experiment was terminated at the
scheduled 30 min; no incapacitation occurred. It was obvious, however, that
these animals were approaching incapacitation; therefore, a second run was
conducted at 350°C and continued until all three animals had expired. The
data from this second run are presented in tue table. The data for the experi-
ments at 375°C and 600°C are the averaged values from two runs at each
temperature.

As the isothermal decomposition temperature was increased (from
experiment to experiment), the production of CO began earlier and proceeded
faster. The animal response times, t; and ty, became correspondingly
shorter and are therefore inversely related to the furnace temperature.
Table Z also contains the maximum CO concentration produced at each
temperature.

The integrated area under a plot of CO concentration versus exposure
time, i.e., Ct-product (ppm-min), was calculated for each individual animal
from the beginning of exposure up to the two response times. This value,
presented as the average for all animals in experiments conducted at a single
temperature, represents a quantity that is related to the "dose”TM of CO that
the animal could have received up to the time of incapacitation (Cty) or
death (Ctg).

In previous studies of exposure to CO alone, we have found these values
to be relatively constant--around 25,000 to 35,000 for Ct; and 70,000 to
90,000 for Ctg. In CO-containing atmospheres that aiso contain irritating
components, the Ct-proaucts (for CO) increase with increasing irritant con-
centration; this is explained by the experimentally documented fact that
respiratory rate and minute-respiratory-volume both decrease when irritants
are present. This effect of irritants always increases Ct; more than Ctg.

On the other hand, when a second toxic gas is present in significant
concentrations along with CO, the Ct-products for CO are always less than
for the case of CO alone. We, therefore, conclude that the major toxic
component of the TDP from Exxon 2380 is carbon monoxide.

The comparison of new Exxon 2380 with a batch that had been drained
from an aircraft engine after 168 hours’ use is shown in Table 3. Each
material was tested at three temperatures under both flaming and nonflaming


Exposure Chamber/Combustion Assembly. The exposure chamber used in
this study, as well as the peripheral analytical, oxygen replenishing,
and combustion equipment, have been described in detail in previous
publications (4,5). The spark ignition assembly described in those ref-
erences was replaced by a simple hot-wire igniter for these experiments.
The apparatus and component sources are shown in Figure 1.

Figure 1. Combustion/Exposure Assembly

1. Gearmotor, Model 3M126, 6 rpm, 1/20 hp; Dayton Manufecturing
Company, Chicago, IL.

2. Animal Exposure Chamber

3. Heating Unit, Model NV2X6, 425 W at 57.5 V, semicylindrical;
Watlow Electric Manufacturing Company, 12001 Lackland Road,
St. Louis, MO.

4. Same as No. 3

5. Thermocouple, chromei-alumei; Omega Engineering inc.,
Stamford, CT.

6. Hot Wire Igniter

7. Combustion Tube

8. Combustion Boat

9. Spring Clamp

10. Smoke Detector


INHALATION TOXICOLOGY: III. EVALUATION OF THERMAL DEGRADATION
PRODUCTS FROM AIRCRAFT AND AUTOMOBILE ENGINE OILS,
AIRCRAFT HYDRAULIC FLUID, AND MINERAL OTL

BACKGROUND

The turbine-powered, propeller-driven (turboprop) aircraft is a
popular configuration, especially in the pressurized, medium-sized,
twin-engined, business category. This efficient and economical power
plant is supplied in at least one version by most major power plant
manufacturers and is used on a variety of aircraft. The combination
represents, therefore, a sizabable and important segment of the commercial
fleet of aircraft.

In 1981 it became a matter of some concern that several unexplained
crashes of these turboprop aircraft might possibly be due to pilot incapaci-
tation from toxic fumes (1,2). It was suggested that such fumes could
criginate in the turboprop power plant and be introduced into the cabin
through the bleed air that is taken from the turbine's compressor and used to
pressurize the aircraft.

One accident involving a turboprop twin-engined aircraft was iavestigated ;
to the extent that both engines were recovered from the lake in which the :
aircraft had crashed. One operational engine was assembled from the parts
of the two engines and tested in the aeronautical engineering department of
a west coast university. Samples of compressor bleed air from this engine
were collected and chemically analyzed.

From this and other studies it has been alleged that a broken carbon
seal in the engine will allow iubricating oil tc enter the compressor i
section; that the resulting oil-contaminated bleed air will enter the cabin;
and that there are present in this bleed air texic substances that can and

will degrade pilot performance or even incapacitate aircraft occupants.

As a result of such allegations and the ensuing rumors, the National
Transportation Safety Board (NTSB) reviewed the accident statistics for this
type of aircraft. They concluded that the frequency and the nature of the
accidents justified additional tests of the quality of the bleed air. The
test hypothesis was that the bleed air contained some substance that was toxic
to the aircraft operator when inhaled.

A particular combination of aircraft and turboprop power plant that
had been mentioned prominently in the news media coverage was the Mitsubishi
MU-2 equipped with Garrett Turboprop Engine Company TPE-331 engines. There-
fore, during the period July 12-25, 1981, a series of tests was conducted at
the Garrett facilities using a TPE-331 mounted on a test stand. For the
tests, the engine was operated under various conditions, including the inten-
tional introduction of known amounts of its lubricating oil (Exxcn 2380 Jet
Engine Oil) directiy inte the air intake of the engine.

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then be rank-ordered according to the shortest t; that was obtained. This
we have referred to as the "worst-case" approach. e third rank-ordering
presented in Table 3 is based on such a philosophy. for each material
there is presented the shorter of the two t,’s obtained and the combustion
mode (FL or NF) for which that response time was produced.

in this listing by worst-case performance, Exxon 2380 again appears
at midrange, Skydrol is most toxic, and Quaker State least toxic. We see
again that five of the seven materials generated their more toxic atmos—
pheres under tlaming conditions, but for Quaker State and paraffin oils the
more toxic smoke was produced with nonflaming thermal decomposition.

All of che experiments that exposed rats to aerosol atmospheres of
three of the materials (new and used Exxon 2380, paraffin oil) gave essen-
tially negative results. Each group of three rats was exposed for 7 hours,
during which time a total weight of lubricant that ranged from 47.2 g to
48.5 g was aerosolized into the chamber airflow. e particle size range
af the aerasals wes not measured, it ranged, however, irom heavier draglets
that settled rapidly, and were available only briefly for inhalation, to
extremely fine particles that remained suspended much longer. Therefore,
the actual fraction of generated aerosol that was inhaled cannot be
reliably estimated.

None of the exposed rats seemed to be adversely affected at the end
of the 7-hour exposure, and all exhibited uormal behavior and weight gain
during the 40-day postexposure observation period. At autopsy no gross
abnormalities were found.

The aerosol exposure using chickens was limited to a singie 7-hour test
with used Exxon 2380 and a 7-nour sham exposure with no aerosol to evaluate
the effects of the restraining system. Each test utilized six chickens: three
in “head-only" restrainers and three that were unrestrained. None of the
exposed animals were incapacitated in 7 hours; all behaved normally during
postexposure observation.

It is widely recognized among combustion toxicologists that the
exact nature of the thermal decomposition products from any material is
dependent on the manner in which thermal degradation is accomplished.
Therefore, the reported results, strictly speaking, apply to these materials
only for the thermal environments that were utilized in these tests.

We feel, however, that the nonflaming mode, especially at the 400°C
temperature, is an adequate model of thermal degradation in tne turboprop
engine, The results obtained under flaming conditions, on the other hand,
would be applicable to a spillage situation (e.g., an accident) in which
such materials are freely burning (flaming).

Based on the results obtained from experiments in the nonflaming mode,
it seems that none of these products generate a quantity of any smoke

>


oti geben eae gn a Re aC IT TT

Technical Report Documentation Page

1. Report No. 2. Government Recession No. ZT Reciienr = Cave.og No.

FAA~AM-83-12 i

‘42 Title and Subtitie 3. Res
INHALATION TOXICOLOGY: ITI. EVALUATION OF THERMAL i APRIL 1983.
DEGRADATION PRODUCTS FROM AIRCRAFT AND AUTOMOBILE DEL Performing O-gene: Coe

ENGINE OILS, AIRCRAFT HYDRAULIC FLUID, AND MINERAL OIL: {

sformiag. Orgon:zotios Resort Ne.
7. Author's) Charles R. Crane, Donald C. Sanders,
Boyd R. Endecott, and John K. Abbott.

9. Performing Organization Name and Address

FAA Civil Aeromedical Institute

P.0. Box 25082 j Ti. Contractor Grons Noe
Oklahoma City, Oklahoma 73125

100 Work Unie No. TRAIS! :

IIB” Type of Resort ond Pouce Covered

12. ‘Sponsering Agency Nome and Address

1
H
Office of Aviation Medicine i
Federal Aviation Administration f

800 Independence Avenue, S.W. Sponsorng Agency ©
Washington, D.C. 20591

15. “Supplementary Notes

This research was conducted under task AM-B-81-TOX-43.

16.. Abstract
A malfunctioning ‘seal in the gear-reduction box of a turboprop aircraft engine H
could allow oil to enter the turbine’s compressor section, which is the source }
of bleed air used to pressurize the cabin. Oil, or its’ degradation products, )
could have a deleterious effect on crew and passengers. A series of tests t
sponsored by the National Transportation Safety Board had examined the possibility j
that contaminated bleed air might contain toxic products identifiable by chemical !
analysis, but none of the gases for which they analyzed were present in toxic con-
centrations. However, the approach did not eliminate the possible presence of an
additional component with significant animal toxicity.

The research reported here examined the toxicity of thermal. degradation products
from aircraft lubricating oils and some related products.. Rats were exposed to
smoke from these products and relative toxicity evaluated in terms of time-to-
incapacitation and time-to-death. The carbon monoxide. (CC) content of the smoke
was measured and this information, in conjunction with the animal response times,
was the basis for concluding that the decomposition of these oils did not produce
any chemical species, other than CO, in quantities sufficient to contribute to the
total toxicity oe

17. Key Words 718. Drstribunon Statement
Combustion Toxicology, Smoke Inhala— Document is available to the public :
tion, Pyrolysis Products, Synthetic _ through the National Technical Informa- -
Lubricants, Turboprop Aircraft. } tion Service, Springfield, Virginia 22161:

19. Security Classil, (of this ceport? 20. Secunty Classii. tof ths page! Ti No. of Pages. | 2, Once ;

i Unclassified Unclassified t 16 : ;
L H

i
Hy i
i

Form DOT F 1700.7 :8~72) Reproduction of completed page authorized



NOTICE

The animals used for this experiment were lawfully acquired and treated

in accordance with the "Guide for the Care and Use of Laboratory Animals"
prepared by the Committee on Revision of the Guide for Laboratory

Animal Facilities and Care of the Institute of Laboratorv Animal Resources,
National Research Council, DHEW Publication No. (NIH) 74-23.

This document is disseminated under the sponsorship of the Department
of Transportation in the interest of information exchange. The
United States Government assumes no liability for its contents or use

thereof.



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