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Jean Christophe Balouet[1]
and Chris Winder[2] Symptoms of Irritation and Toxicity in Air Crew as a Result of Exposure to Airborne Chemicals in Aircraft
Reference:
Balouet, J.C. and Winder, C., Symptoms
of Irritation and Toxicity in Air Crew as a Result of Exposure to Airborne
Chemicals in Aircraft Air Quality and
Comfort in Airliner Cabins, ASTM STP 1393,
N. L. Nagda, Ed., American Society for Testing and Materials, West
Conshohocken, PA, 2000. Abstract Materials used in the operation
of aircraft may contain hazardous ingredients, some with significant
toxicities. Some leak events can result, with personnel and passengers being
exposed via in-cabin air contamination. Occassionally, short term intense or
long term low level exposures may be of a magnitude to induce irritation
and toxicity symptom.
Six new case studies connected to exposures to airborne contaminants
from engine oil or other aircraft fluids are described, and temporally
juxtaposed by the development of a consistent symptomology of irritancy, short
term skin, gastro-intestinal, respiratory, nervous system effects, and long
term central nervous and immunological effects. Symptoms may be reversible
following brief exposures, but features are emerging of a chronic syndrome
following significant exposures with implications for air safety and
occupational health. Keywords case studies, airborne chemicals, chemical
safety, irritancy, neurotoxicity, phosphate esters. Introduction
Aircraft materials such as jet-fuel,
de-icing fluids, engine oil and hydraulic fluids contain a range of
ingredients, some of which are toxic [1,
2, 3]. For example, the aviation
industry has used engine oil or
hydraulic fluids containing toxic ingredients such as organophosphates,
including tricresyl phosphates (TCP), tributyl phosphates (TBP), triphenyl
phosphates (TPP) and their derivatives. Although these aircraft chemicals are usually retained in the engines and equipment into which they have been added, they can sometimes find their way into cabin air where crew and passengers are located, through incidents such as engine oil leaks, seal failure and fluid ingestion by APU (Auxiliary Power Unit)/engines. APU pack burn outs can also give rise to significant cabin air contamination. Significant chemical contaminants (see
also Thomas Dumhyam and Chris Van Netten at this conference) include:
aldehydes; aromatic hydrocarbons; aliphatic hydrocarbons; chlorinated,
fluorinated, methylated, phosphate, nitrogen compounds; esters; and oxides. Inhalation is an important route of
exposure, with exposure to uncovered skin being a second, less significant
route and ingestion by air crew is improbable. Symptoms following irritating and toxic exposures Studies of exposures in airplanes includes a
1983 study of eighty nine cases of cockpit smoke/fumes events in the US Air
Force [4], a 1983 study of Boeing 747
flight attendants in the USA [5], and a
1998 study of BAe 146 flight crews in Canada over a four-month period [3] . There
are common themes in symptom clusters in these studies, as shown in table 1
below. Table 1: Studies
reporting symptoms of irritancy and toxicity in aircrew. Blank cases correspond to specific symptoms not
listed in studies.
The range of symptoms in these studies is quite broad, affecting many
body systems. In some cases, it is
quite likely that symptoms in one study are similar to those in the others (for
example, trouble in thinking and counting and cognitive problems). A preponderance of the symptoms reported above are related to exposure to an irritant. Indeed, the earlier Tashkin study [5] suggests ozone as a cause, even though a battery of pulmonary function tests failed to reveal abnormalities. However, the presence of symptoms related to central nervous system dysfunction, hair loss, muscular and gastrointestinal problems, suggests the possibility of other chemical contaminants of systemic toxicity. Six
new case studies Six new cases of symptom development from such exposure events were investigated. They were taken from flight crew and flight attendants in four airlines operating in four countries and in three airplane models. A summary of the effects is shown in table 2 below. Table
2: Symptom Summary: Six Case Studies
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