Submitted to

The Aviation Subcommittee of

The Transportation & Infrastructure Committee

U.S. House of Representatives


June 3, 2003




Prepared by the

Association of Flight Attendants, AFL-CIO

Washington, DC



This systematic overview of problems with aircraft air quality is submitted on behalf of the Association of Flight Attendants (AFA), a labor union that represents more than 50,000 flight attendants at 27 different airlines. At the heart of the failure of the US Federal Aviation Administration (FAA), the manufacturers, and the airlines to resolve problems with aircraft air quality is their failure to acknowledge problems with aircraft air quality. There are no standards for protective measures or access to information necessary to prove individuals’ cases; there is effectively no government oversight, allowing the steady flow of "anecdotal" reports to be dismissed as unreliable, and therefore irrelevant.


It is no small task to describe and document problems with air quality on aircraft; hence, the length of this submission. The problems are varied, but the lack of oversight and protective measures is common to all and is in desperate need of remedy. Here, seven problems with aircraft air quality are described in detail, each accompanied by a series of proposed actions. The highlights are described here:


Inadequate ventilation: In buildings, owners must meet minimum ventilation standards intended to protect occupant health and comfort. On aircraft, there is no ventilation standard, despite the fact that aircraft are the most densely occupied of any environment. In buildings, workers can request an OSHA investigation of indoor air quality. On aircraft, there is no government body assigned to investigate related illness reports. Further, there are no protections in place for flight attendants assigned to fly to areas affected by Severe Acute Respiratory Syndrome (SARS), even though crewmembers do not have the option of "postponing non-essential travel." The World Health Organization recognizes flight attendants as potential "close contacts"; the Centers for Disease Control and Prevention does not.  (Pages 6-14)


Polluted air supply on the ground. Exhaust fumes and heated deicing fluids can be ingested into the air supply systems, especially during ground operations. (Page 14-15)


Exposure to heated oils and hydraulic fluids. Heated oils and hydraulic fluids can leak or spill into the air supply systems during any phase of flight, potentially exposing passengers and crew to carbon monoxide and neurotoxins, such as tricresylphosphates. There are almost no protective measures in place to prevent air supply contamination, and contaminated aircraft can be – and are - dispatched as "airworthy."  Chronic or even permanent neurological damage can result, although affected passengers and crew have little recourse without any record of air monitoring or access to maintenance records. Pilot incapacitation is an additional risk. The FAA has shown no signs that it plans to follow the recent National Research Council committee recommendation for requisite carbon monoxide monitoring on all flights.  (Pages 15-21)


Reduced oxygen in the ambient air during flight.  During flight, the aircraft cabin is maintained at a reduced pressure, generally equivalent to an altitude of 6,000 – 8,000 feet, although sometimes higher. At an effective altitude of 8,000 feet, the supply of oxygen is reduced by 25% relative to sea level. There is evidence that the current "8000 feet standard", first issued in 1957, is based not on health, but on operating costs, and that the reduced oxygen supply may be inappropriately low for a substantial portion of the flying public. (Pages 22-25)


Inadequate attention to the thermal environment. Providing air nozzles ("gaspers") at each occupant seat and work area allows flight attendants and passengers to adjust the temperature of their environment. This is especially important in areas where flight attendants are physically active. In addition, flight attendants regularly report that the galleys and jumpseats located near the aircraft doors can be uncomfortably cold at ankle level, presumably because the doors are poorly insulated. A standard that defines a target temperature range and maximum vertical and horizontal temperature differentials would address this problem. Door heaters have already proven an effective and practical remedy. (Pages 25-26)


Exposure to ozone gas: Symptoms associated with ozone exposure are well documented and include respiratory distress and increased susceptibility to infection. Ozone levels increase with altitude and latitude, and are highest in the late winter and early spring. The exposure limit for ozone cited in the Federal Aviation Regulations is 2.5 times higher than the workplace limit set by the National Institute for Occupational Safety & Health. Airlines are under no obligation to monitor or record ozone levels in the cabin. (Pages 26-29)


Exposure to potentially high concentrations of pesticides: Some countries require that incoming aircraft are sprayed with pesticides to kill any insects that may be on board and may carry disease. The pesticides are applied in occupied or soon-to-be-occupied aircraft cabin without any measures to inform or protect the health of passengers or crew. Reported symptoms range from sinus problems and rash to anaphylactic shock and nerve damage. Differences in exposure levels and individual susceptibilities are described. The US Department of Transportation’s investigation into the feasibility and efficacy of non-chemical methods to keep aircraft cabins insect free must be actively supported. (Pages 30-34)


On behalf of our 50,000 members, AFA thanks the members of the Aviation Subcommittee for considering these comments.




AFA            Association of Flight Attendants, AFL-CIO

ASHRAE    American Society of Heating, Refrigerating, and Air Conditioning Engineers

APU            Auxiliary Power Unit (a key component of aircraft air supply system)

BLS            US Bureau of Labor Statistics

CDC           US Centers for Disease Control & Prevention

CFM/p        Cubic feet of outside air per minute, supplied to each person (a measure of ventilation rate)

DOT           US Department of Transportation

FAA            US Federal Aviation Administration

OSHA         US Occupational Safety & Health Administration

NIOSH        US National Institute for Occupational Safety & Health

ppm            parts of contaminant per million parts of air

(used as a measure of airborne concentration)

SARS                   Severe Acute Respiratory Syndrome

SLE             Sea level equivalent pressure  (a measure used to standardize ventilation rates and contaminant concentrations)

TCPs          Tricresylphosphates

WHO          World Health Organization

Summary of aircraft quality problems, impact on the health of passengers and crew, and proposed actions.




Health Impact

Proposed Actions

1.      Inadequate ventilation

·     Reports of stuffy, smelly air and symptoms of "sick building syndrome"

·     Increased risk of disease transmission

·       Establish a minimum ventilation standard for aircraft in operation, including the current fleet.

·       Require gaspers on all aircraft types.

·       Recognize flight attendants as at-risk for SARS transmission on aircraft.

2.      Exposure to exhaust fumes and deicing  fluid, especially during ground operations

·     Reports of respiratory irritation, headache, nausea, etc. attributed to exposure to heated deicing fluids and exhaust fumes.

·       Implement specific preventive measures to reduce the ingestion of exhaust fumes and deicing fluids into the air supply system.

3.      Exposure to air contaminated with heated hydraulic fluids and oils.

·     Reports of serious symptoms, including tremors, tunnel vision, and memory loss associated with "smoke in the cabin incidents." Symptoms are consistent with exposure to carbon monoxide and neurotoxic components of oils and hydraulic fluids.

·       Require in-duct carbon monoxide monitoring on all flights and train pilots to respond to elevated levels.

·       Implement specific preventive measures to prevent the contamination of air supply systems, already proven effective at airlines in other countries.

·       Ensure that crew and passengers with particular medical documentation have timely access to specific airline records necessary to prove their case.

4.      Inadequate oxygen during flight

·     Reports of hypoxia (dizziness, fainting, tunnel vision) and in-flight cardiovascular or respiratory emergencies.

·       Issue an operating standard consistent with the original operating intent of the existing design standard (i.e., 5,000-6,000 feet cabin altitude). At the very least, collect blood oxygen saturation data from active cabin crew and a cross-section of passengers to determine necessary cabin altitude requirements.


(Continued on next page)



Health impact

Proposed Actions

5.   Inadequate attention to the thermal environment

·     Regular reports of discomfort caused by cold air radiating from poorly-insulated doors into crew work areas. Also, gaspers that allow passengers and crew to adjust their local temperature are only optional.

·        Establish a target temperature range and maximum allowable temperature differentials (horizontal and vertical). Door heaters have proven an effective remedy to maintain reasonable temperature differentials in areas adjacent to poorly insulated doors.

·       Require gaspers at individual seats and crew work areas.

6. Exposure to ozone gas

·     Reports of respiratory distress consistent with ozone exposure. FAA exposure limit is not health based (e.g., 2.5 times higher than the NIOSH limit set for workers). No air monitoring provisions for ozone

·       Establish a health-based ozone standard.

·       Require monitoring on high-latitude flights and other elevated ozone areas during  "ozone seasons."

·       Require that catalytic converters installed on aircraft that fly polar routes during ozone seasons be replaced more often.

7. Exposure to pesticides

·     Reports of symptoms associated with exposure to pesticides and solvents, including anaphylactic shock. Exposures can be significant and are unregulated.

·       Actively support the DOT-chaired task group that is investigating the feasibility and efficacy of mechanical methods of disinsection to replace current chemical spraying methods that jeopardize crew and passenger health.