Maybe you’ve seen me and my family on a flight between Hawaii and the Mainland. We were the people sitting uncomfortable in our seats with white, cotton gloves, a sweatshirt with hood covering our heads, and a face mask. The rest of the passengers were typical American flyers, oblivious to the pathogenic germs that surrounded them.

As a medical anthropologist I am sensitive to the health hazards of flying. Apart from the mechanical problems that can cause issues, there is the radiation exposure, exposure to internationally-sourced pathogens, low cabin pressure with low oxygen content, and dehydration. But it wasn’t until I started to plan a trip “down under” to New Zealand and Australia that I realized another toxic aspect of flying.

Airlines going to certain countries must spray passengers and their luggage with pesticide to kill insects. This is sometimes done right before takeoff, as flight attendants walk down the aisle with a pesticide spray can in each hand, fumigating the entire plane and its passengers and luggage with pyrethrin or d-pyrethroid insectside. You then have to breathe in this spray for the full flight time under pressurized cabin conditions. Other times, the spraying is done just before letting passengers leave the plane on arrival. The other method of application is a long-lasting residual spraying of the interior of the plane when passengers are not onboard. Sometimes, the plane is pre-sprayed with long-lasting spray followed by fumigation when passengers are onboard.

The World Health Organization requires this spraying to prevent the spread of disease-causing mosquitoes and other insect pests. Some places, like Australia, New Zealand, and Tahiti, require all in-bound flights from anywhere to be sprayed. The WHO claims that, “Passengers are sometimes concerned about their exposure to insecticide sprays during air travel, and some have reported feeling unwell after spraying of aircraft for disinsection. However, WHO has found no evidence that the specified insecticide sprays are harmful to human health when used as recommended.” They fail to mention that the lack of evidence is from a lack of research.

One study explains that, “Although approved by WHO for aircraft disinsection, certain adverse health effects on cabin crew and flight attendants, such as dizziness, nausea, fatigue and mild disturbance of consciousness, have been reported by various researchers. Recent toxicological studies have also identified adverse neurological effects, age-related disease, and abnormal development of fetal brain in rats and mice resulting from exposures to pyrethroids.”

The Centers for Disease Control claims that flight crew and passengers have been harmed by disinsection. In addition, pesticides cannot be used outside of their approved uses, and no pesticide has been approved by the EPA for use in passenger cabins on commercial aircraft.

The CDC article concludes with the following observation.

Research gaps

•It is unknown whether long-term exposure to the chemicals used in aircraft disinsection might cause health effects in air and ground crew.

•Pesticides used for aircraft disinsection are mixtures including solvents, propellants, surfactants, and synergists. Research on the health effects of exposure to these mixtures, as well as possible combined effects with other chemicals present in aircraft environments, are needed.

•Although pyrethroid pesticides are generally not believed to cause allergy or asthma symptoms, allergic sensitization, asthma symptoms, and anaphylaxis (a sudden and severe allergic reaction) have been reported related to exposure to commercial aircraft disinsection products.Additional research is needed to clarify the relationship between disinsection and asthma/allergy.

•Reports from passengers and air crew suggest that there are major differences in how disinsection is performed. Better understanding of current practices is needed.

•Further studies of aircraft surfaces and air crew are needed to evaluate whether repeated applications of insecticides in a cabin, or improper application of pesticides in aircraft, might cause increased exposure.

•Some insects are resistant to the pesticides used in aircraft disinsection. Research to evaluate the usefulness of chemical disinsection, as well as non-chemical and engineering controls that can be used as an alternative, is needed.

FYI, here are places where you will be sprayed. Frankly, I didn’t know about disinsection spraying for trips to Australia or New Zealand until I called Fiji Airways to speak with a ticket agent. The voice message while I waited announced that they treat all flights with pesticide to prevent the introduction of pests. I didn’t yet realize that disinsection was a requirement for all carriers, so I decided to check into Hawaiian Airlines, my hometown carrier, to see if they did the same.

I discovered that Hawaiian Airlines also uses disinsection on flights, which they explain on their website.  However, unlike Fiji Airways, Hawaiian Airlines does not let customers know up front about the spraying. Unless customers search the Hawaiian Airlines website for disinsection, nothing is told to customers about being sprayed until they are in the plane and the flight attendants are beginning the fumigation.

There was one time in the past when I experienced being sprayed on a plane. It was about 20 years ago, on a flight from Thailand to the UK. It was a terrible feeling being forced to breathe pesticide. Usually, we avoid breathing in these poisons, so when you’re forced to breathe it on a closed airship with recirculated air, there is an instinctive recoil and sense of horror. Why would Hawaiian Airlines not let passengers know about being sprayed before entering the plane?

I asked the management of Hawaiian about this in an email. I wrote:

Hawaiian Airlines flights to Australia, New Zealand, and Tahiti are subject to disinsection.

I realize that disinsection is required by these destinations. However, it has come to my attention that HA does not inform passengers that they will be sprayed with pesticide until after the passenger has boarded the plane.

While disinsection may be mandatory for those destinations, it does not justify HA waiting to notify passengers that they will be subject to spraying until the passengers have boarded. As you may know, some airlines, such as Fiji Airways, inform potential customers of their disinsection requirements up front, prior to ticket purchase. This seems reasonable given the potential for adverse health reactions to the spray, and the desire by some passengers to not be sprayed by pesticides for personal, health reasons.

Is there a reason why HA does not give advanced notice of disinsection to passengers to these destinations prior to ticket purchase?

What would be the procedure if someone objected to being sprayed while onboard?

Are there any mitigations offered by HA to passengers prior to spraying, such as the use of masks?

Thank you for helping me understand HA procedures concerning this use of pesticide on passengers and the lack of advanced notice.

Here is their reply:

On behalf of Hawaiian Airlines, I understand your concern regarding the disinsection procedures we follow while flying to Australia, New Zealand and French Polynesia.

The treatment, which is intended to prevent harmful pests from entering these destinations is required by each government and their authorities. All airlines arriving in Sydney, Brisbane, Auckland, and Papeete must meet the stringent requirements for insect control. Other airlines may elect to treat the entire aircraft by saturating it with the chemical on a periodic basis. Hawaiian Airlines elects to have the aircraft sprayed upon arrival, which reduces exposure for our guests.

As disinsection is a requirement by the governments of Australia, New Zealand, and French Polynesia, we currently don’t provide messaging about the disinsection process upon purchasing a ticket to destinations in our South Pacific destinations. Please know that we’ve shared this with our Web Support Team for their review in order to add specific travel information for these cities.

Our flight attendants are required to make the disinsection announcements after each flight has safely landed. If a guest insists on getting off the aircraft for health reasons, they first must advise any flight attendant upon hearing the announcement. The governments of Australia and New Zealand will allow guests to disembark during the on-arrival disinsection treatment of the flight, but they require that all carry-on items to remain on board for the process. Guests will be allowed back on board by the Quarantine officers once the disinsection process has been completed to collect their items.

We do not offer any mitigation to guests during the spraying process, although guests are free to use their own masks. We make it known prior to disinsection that the spray we utilize is non-toxic to humans and approved by the World Health Organization and Australasian authorities.

While flight crew members and some passengers may disagree that the spray is non-toxic to humans, at least Hawaiian Airlines has apparently agreed to make the issue known up-front on their website. We’ll see how they accomplish this.

The other question is what happens when a sprayed plane is used for flights to other places that don’t require spraying, needlessly exposing passengers to pesticide residues. I asked a Hawaiian Airlines customer service person if airplanes remain dedicated to certain flights, or are shuffled to other routes. This is an issue for United Airlines, which sends its disinsected, pesticide-coated planes to Mainland routes, which means passengers to LAX or San Francisco, for example, are unintentionally exposed to pesticides meant for passengers going to spray-requiring countries. I was told that Hawaiian does not do this. Pesticide contaminated planes are only used on flights to disinsection destinations.

One other issue to keep in mind is when traveling with pets. Cats are not able to metabolize the pesticides used on planes, and can die. So if you are traveling with a cat, you may want to choose a different destination.

Meanwhile, you may want to do what we do when traveling. Wear gloves at all times, keep your body covered to prevent skin contact with pesticide (and germ) coated surfaces, cover your head with a hoodie, and wear a face mask. You may also want to select travel destinations based on whether or not you will be fumigated. Travel may be fun, but it’s no fun when you are poisoned.

We also need a determined effort to find alternatives to using pesticides. While the dangers of spreading disease through air travel is real, the solution should not itself be a health threat. Most importantly, people have the right to know about being sprayed so they can make informed choices with their travel plans, and their health.