Memorandum by Association of Flight Attendants
On behalf of our 55,000 members of the Association
of Flight Attendants-CWA, AFL-CIO (AFA), employed at 20 airlines
here in the United States, the Association is responding to the
call for evidence for the "Air Travel and Health" follow
up inquiry.
Specifically, we wish to provide information
that has emerged since your 2000 inquiry on the following two
health concerns for occupants on commercial aircraft: (1) Exposure
to insecticides applied in the cabin and flight deck, largely
to comply with foreign quarantine regulations of 47 countries;
and (2) Exposure to pyrolyzed engine oil and hydraulic fluid that
sometimes contaminate the aircraft air supply.
EXPOSURE TO
INSECTICIDES
1. Paragraph 4.28 of the 2000 Report notes
that "some health authorities have queried the wisdom of
aircraft disinsection", but still concludes that "insect
control procedures are not a significant health issue" based
on the apparent paucity of specific reports. The shortage of independently
verified data must be noted in the context of the following facts:
(i) Neither passengers nor crewmembers are
informed of residual spraying requirements so they do not know
what they have been exposed to;
(ii) Passengers and crew are only informed
of in-flight spraying requirements during the flight and are formally
assured that the sprays are safe;
(iii) Airlines need not provide either passengers
or crew information on the contents of either the residual or
inflight sprays;
(iv) Passengers and crew can and do report
symptoms to the airlines and to their physicians, but airlines
need not publicise or share these reports and physicians need
not report them to a centralised database to facilitate public
health alerts; and
(v) There is no centralised reporting system
that monitors this or any other crew or passenger health concern.
For these five reasons, it seems premature—and even irresponsible—to
dismiss the health concerns associated with disinsection practices
without conducting a formal and independent investigation into
the prevalence of reported symptoms on such flights.
2. In 2000-01, the California Department
of Health Services investigated reports of acute illness reported
to physicians by cabin crew and attributed to insecticide exposure
on aircraft. Recently, a peer-reviewed paper was published on
the results of that investigation (Sutton, 2007). Chronic health
effects attributed to exposure to pyrethroid insecticides on aircraft
have been reported widely to crewmembers' physicians and to our
union, but funding to conduct a controlled, detailed investigation
has not been available.
3. In early 2002, the United States (US)
Department of Transportation (DOT) initiated an inter-agency task
group with input from six other US Government agencies. Its goal
is to develop and assess the efficacy and feasibility of a method
of disinsection that could be achieved through mechanical means
instead of chemical spraying. Since then, members of the inter-agency
task group have tested the efficacy of simple air curtain technology
to keep insects off aircraft (or on aircraft, depending on the
direction of the airflow and according to the arrival or departure
point in question), intended to protect a passenger boarding door
equipped with a boarding bridge. This work has since been published
in the peer-reviewed literature (Carlson, 2006). The group is
now finalising testing on a custom net curtain solution intended
to prevent insect entry through the aircraft service doors and
through passenger boarding doors equipped with stairs. The group
is also in talks with several interested countries.
4. Finally, since your 2000 inquiry, the
International Civil Aviation Organization updated its Standard
2.24 to allow countries to adopt WHO-approved non-chemical methods
of disinsection as an alternative to the typical chemical methods
(ICAO, 2004). I encourage you to investigate these options further
as part of your follow-up inquiry.
Pyrolyzed engine oils in the aircraft air supply
("contaminated bleed air")
5. There is little dispute that engine oil
and hydraulic fluid can and does contaminate commercial aircraft
air supply systems (Bobb, 2003; NRC, 2002; SAE, 1997), and that
when this happens, flight safety can be compromised (AAIB, 2007;
AAIB, 2004; CAA, 2001; CAA, 2000). However, despite the volume
of documented crewmember symptoms that span decades of flying
(Michaelis, 2003; Witkowski, 1999; Rayman, 1983; Montgomery, 1977),
there is still a diversity of opinion on the severity of health
impact because there are no air quality monitoring data collected
during an event, no standardized medical test to definitively
prove exposure, and no diagnostic tests to definitively prove
the relationship between exposure and reported symptoms.
6. The frequency of air supply contamination
events is also under dispute because of underreporting and the
absence of a comprehensive source of reports. In March 2007, James
Burin, Director of Technical Programs for the Flight Safety Foundation,
estimated that five to ten aircraft per day are diverted around
the world due to smoke-fire-fumes events, most of them smoke.
This estimate was based on accident/incident research and discussions
during international meetings with airlines and manufacturers,
but he did not know how many of these were caused by oil or hydraulic
fluid. Other sources of smoke/fumes include in-flight fires and
electrical faults. Of course, any source of smoke or fumes in
the flightdeck/cabin creates a potential health and safety hazard,
but AFA has been especially concerned about such fumes that contain
engine oils or hydraulic fluids because they contain some very
toxic ingredients.
7. In 2002, the US National Research Council
published the following frequency estimates for air supply contamination
with engine oil or hydraulic fluid for a small selection of aircraft
types, all presented as number of events per 1,000 flight cycles:
3.88 for the BAe146; 1.29 for the A320; 1.25 for the B747; 1.04
for the DC-10, 1.02 for the MD80, 0.63 for the B767, and 0.09
for the B737 (NRC, 2002). These estimates were based on several
years of data from three airlines. To put these numbers in context,
there were an estimated 10,556,000 departures on US airlines last
year (BTS, 2007), so even the most conservative estimate of 0.09
events per 1,000 flight cycles fleet-wide, for example, translates
into 950 events per year in the US fleet or an average of two
to three events every day.
8. I am in the midst of compiling smoke/fumes
incident data from the following four sources:
(i) Copies of reports that our members submitted
to their airlines, assuming that they also reported the events
to AFA;
(ii) News media reports, typically of diversions
or major delays due to smoke or fumes (not always specific as
to source of smoke);
(iii) Reports that US airlines submitted
to the Federal Aviation Administration (FAA) Service Difficulty
Reporting system (per 14 CFR 703); and
(iv) Reports that US airlines submitted to
the Aviation Incident Database System. The dataset is restricted
to those events that involved a smoke, fume, mist, haze, or odor
likely or definitely caused by pyrolyzed engine oil or hydraulic
fluid.
Events for which another cause (such as an electrical
fault or de-icing fluid) could be identified are excluded. Data
collection and analysis is ongoing but from these four incomplete
and largely underused sources of information, I have documentation
on 293 events for a 16.5 month period (1 January 2006-11 May 2007),
translating into an average of 0.59 events per day on the US fleet
alone that likely or definitely involved engine oil or hydraulic
fluid in the cabin/flight deck. These four data sources are a
starting point, but aside from the fact that the data collection
is ongoing, they are guaranteed to underestimate reality for the
following reasons:
(i) Our union, AFA, only represents about
half of the flight attendants in the US, so we only have the potential
to review about half of the contamination events reported by flight
attendants, assuming that these events are neither more nor less
common at AFA airlines. Further, there is no guarantee that AFA
members will send a copy of their airline report to the union,
or if they do, that our particular department will get a record
from either the member or the local union office. So, at best,
we had access to a fraction of the events documented by US flight
attendants with their airlines.
(ii) Airlines under-report to the FAA. Specifically,
the FAA requires airlines to report "each failure, malfunction,
or defect concerning an aircraft component that causes accumulation
or circulation of smoke, vapor, or toxic or noxious fumes in the
crew compartment or passenger cabin during flight" to its
Service Difficulty Reporting (SDR) system per Federal Aviation
Regulation (FAR) 703(a)(5). Airlines must also report ground-based
events that involve a failure, malfunction, or defect that has
endangered or may endanger the safe operation of the aircraft
per FAR 703(c). However, in May 2006, the FAA distributed a bulletin
to its inspectors stating that "it appears as though there
are numerous air carriers/operators who may not have reported
these [smoke/fumes in the flight deck/cabin] events as required
by regulation" (FAA, 2006). Put simply, even the FAA recognises
that airline compliance with its reporting rules is poor. As an
example, of the 105 events recently documented by our members
with their airlines, I was only able to identify four in the FAA
databases. Similarly, of the 39 smoke/fume events identified in
the media (typically serious enough to require a diversion), I
was only able to identify three in the FAA databases.[4]
(iii) Airlines need not monitor the air so
for an event to be reported, there must be sufficient contamination
for crewmembers to either smell or see the problem, and they must
fill in the paperwork knowing that there is a high probability
that the incident will get ignored and any associated workers'
compensation claim will be denied. Under-reporting (both intentional
and unintentional) by crew is a real problem and it is hard to
overcome the obstacles of no inflight warning systems, low morale,
and low expectations of an appropriate response from the airlines.
9. Of the events with complete phase of
flight information, a little more than half diverted. Many of
those that did not divert were either in descent or taxi-in, so
instead conducted emergency landings. We do not have enough information
to know if the subsequent flights were cancelled, but presumably
they would have at least been delayed so that maintenance staff
would have time to troubleshoot.
10. The fact that about half of these events
required a diversion and likely all caused potentially expensive
and unpopular delays is important because it presents a business
case for preventing these events with improved maintenance practices
and air cleaning equipment, and it justifies the investment in
sensor equipment designed to identify an event in its early stages.
In 2006, the FAA estimated the average cost of a diversion at
$207,000, obviously varying by size of aircraft and requisite
ground time to troubleshoot and fix any mechanical failure. So,
some or all of the cost of air cleaning equipment for the outside
air will clearly reduce diversion costs associated with smoke
and fumes. Similarly, some or all of the expense of chemical sensor
equipment that allows an airline to identify and address minor
problems before they become serious and costly may be offset by
saved diversion costs. For example, one major US airline submitted
a report to the FAA last year of an extremely foul odour from
the air packs after liftoff. It described the forward and aft
cabin air quality as poor but noted that maintenance found no
evidence of an oil leak. On that same aircraft eight days later,
strong fumes entered the flight deck at takeoff and remained through
the climb. Maintenance finally identified three oil leaks and
replaced the engine. That later event could have been prevented
had there been some objective indication of oil leaking in the
cabin on the earlier flight or if the aircraft had been equipped
with air cleaning equipment.
11. In closing, we know that, by definition,
the outside air supplied to the cabin and flight deck is first
processed in the engines or APU where it can be contaminated with
pyrolyzed engine oil or hydraulic fluid. The only exception to
this rule is the B787 that will enter service in 2008 and rely
on a non-bleed air system, both on the ground and inflight. To
this end, the frequency and potential severity of air supply contamination
events present an obligation for government bodies to investigate
and promote preventive and remedial measures. Options include
installing commercially viable air cleaning devices on the outside
air supply, prompt and effective cleaning of contaminated systems,
and an obligation to inform crew and passengers of onboard exposures.
On behalf of our members, we thank you for your
interest in these exposures onboard commercial flights.
18 June 2007
References
AAIB (2007) Bulletin no 4/2/07, Bombardier DHC -8-400,
G-JECE (EW/C2005/08/10), UK Air Accidents Investigation Board.
AAIB (2004) Report no 1/2004, BAe146, G-JEAK (EW/C2000/11/4)
UK Air Accidents Investigation Board.
Bobb, AJ (2003) Known harmful effects of constituents
of jet oil smoke TOXDET-03-04 Naval Health Research Center
Detachment (Toxicology), Wright-Patterson AFB, OH.
BTS (2007) Airline Activity: National Summary
(US Flights). Bureau of Transportation Statistics, US Department
of Transportation, Washington, DC. See www.transtats.bts.gov
CAA (2001) Flight Operations Department Communication
(FODCOM) 14/2001 UK Civil Aviation Authority, Safety Regulation
Group, Aviation House, Gatwick, West Sussex, England.
CAA (2000) Flight Operations Department Communication
(FODCOM) 17/2000 UK Civil Aviation Authority, Safety Regulation
Group, Aviation House, Gatwick, West Sussex, England.
Carlson, D A; Hogsette, J A; Kline, DL; et al
(2006) "Prevention of mosquitoes and house flies from entering
simulated aircraft with commercial air curtain units" J
Econ Entomol, 99(1): 182-193.
FAA (2006) Flight Standards Information Bulletin
for Air Worthiness (FSAW) 06-05A "Guidance for smoke/fumes
in the cockpit/cabin" US Federal Aviation Administration,
Washington, DC.
ICAO (2004) Meeting of the Facilitation (FAL) Division
of the International Civil Aviation Organization, Working Paper
117 (FAL/12—WP/117), Cairo, Egypt.
Michaelis, S (2003) "A survey of health symptoms
in BALPA B757 pilots" J Occup Health Safety-Aust
NZ, 19(3): 253-61.
Montgomery, MR; Wier, GT; Zieve, FJ; et al
(1977) "Human intoxication following inhalation exposure
to synthetic jet lubricating oil" Clinical Toxicol,
11(4): 423-26.
NRC (2002) The airliner cabin environment and
the health of passengers and crew US National Research Council,
ISBN 0-309-08289-7, National Academy Press, Washington, DC.
SAE (1997) Aerospace Information Report 1539 Rev
A. Society of Automotive Engineers International, Warrendale,
PA.
Sutton PM, Vergara X, Beckman J, Nicas M, Das R.
(2007) "Pesticide illness among flight attendants due to
aircraft disinsection" Am J Ind Med, 50: 345-356.
Witkowski CJ (1999) "Remarks on airliner air
quality" Presentation at semi-annual conference of the American
Society of Heating, Refrigerating, and Air Conditioning Engineers
(ASHRAE), Chicago, IL.
4 The compilation of reports submitted to the FAA during
this period is about 90% complete so we may ultimately conclude
that the airlines reported a greater number of events to the FAA
than these numbers suggest, but dramatic under-reporting is still
evident. Back
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