Radiation of Airline Passengers by “Dark Lightning”?

This is the type of lightning you can typically see during a thunderstorm — but there is also apparently a different kind of lightning called dark lightning, which you typically cannot see. Photograph ©istockphoto.com by Martin Fischer..

FlyerTalk members have long been concerned with being exposed to radiation during their travels — whether it is by being screened at an airport security checkpoint, or simply by flying as a passenger aboard a commercial aircraft — as they do not want to increase their chances of being diagnosed with such diseases as cancer.

The levels of radiation and their effect on your safety have also been long debated. For example, FlyerTalk member UAConcorde learned from a lecture that frequent fliers who travel between 100,000 miles and 450,ooo miles per year are subject to radiation exposure equivalent to a scan of your pelvis, or 60 X-ray images of your chest; and FlyerTalk member spideysense was advised by both a doctor and a technician “that the radiation from an X-ray is very low and that flying in a plane exposes you to much more radiation.”

There are also conflicting reports about the radiation exposure levels and safety of the equipment used to scan passengers who are being screened daily at airport security checkpoints: for example, one report claims that there is no significant threat of radiation from being scanned and that the equipment is operating safely; while another report claims that no levels of radiation can be considered safe, no matter how low is the purported amount.

Now both The Washington Post and NBC News have reported on a phenomenon of brief but powerful terrestrial gamma-ray flash known as dark lightning — originating naturally from thunderstorms similarly to lightning but is virtually invisible due to emitting an insignificant and extremely brief glow of bluish-purple light, hence its name — which generates electrons and positrons and propels them towards space, possibly blasting airline passengers with large doses of gamma rays on a regular basis.

Because there is supposedly not enough information and understanding pertaining to the cause of dark lightning, attempts to discover whether or not it poses a radiation hazard to airline passengers have been limited — although the flashes do not seem to reach what are considered “truly dangerous levels.”

Scientists calculate that the amount of radiation near the tops of cumulonimbus clouds which produce thunderstorms is roughly equivalent to “ten chest X-rays, or about the same dose people receive from natural background sources of radiation over the course of a year.” However, the radiation is approximately ten times greater in the middle of a thunderstorm — which airline pilots attempt to avoid as much as possible — “comparable to some of the largest doses received during medical procedures and roughly equal to a full-body computed tomography scan.”

Because the doses of radiation supposedly never reach “truly dangerous levels”, there is generally no need to worry — although it is something about which to keep in mind until more information is discovered, as dark lightning seems to be more of a topic of interest for those who enjoy science rather that perceive it as a health threat. However, I would be curious as to whether or not a study exists on comparing rates of cancer between those people who fly frequently and those who do not.

I would think that if frequent fliers do have a higher risk of contracting cancer than their non-traveling brethren, the difference would be insignificant at best. Regardless, I think I will continue to take my chances of traveling via airplane all over this wonderful planet of ours and visiting as many places as possible before I die — and enjoy the added bonus of watching that mesmerizing light show created by thunderstorms below the aircraft during a flight, especially at night — even if that means that I might be shortening the span of my life by a few days due to my exposure to radiation…

Comments (Showing 5 of 5)

  • oktoberfest at 9:26pm April 10, 2013

    A better test would be to check the pilots and flight attendants. They must be getting the most radiation.

  • 91StealthES at 5:51am April 12, 2013

    If the radiation exposure was an issue with the flight attendants and pilots, they would be issued radiation badges to monitor their exposure.

    Before entering the corporate world, I worked with liquid, powder and emitted radiation and had to wear a ring and body badge to measure both exposures. I never had my badges read above the accepted exposure limit and I handled radiation everyday.

    I guess I should be really “scared” as I still routinely visit the hospitals for business and fly over 100,000 a year.

    It would be interested to see if the flight attendants or pilots are provided body badges to measure their exposure. As mentioned, being we haven’t heard of this, it must not be that large of an issue.

  • robbarish at 1:29am April 15, 2013

    The National Council on Radiation Protection and Measurements (NCRP) publishes periodic reports on the occupational exposure of radiation workers in all industries. And, yes, flight attendants and aircrew are considered to be radiation workers. In their latest report on occupational exposures, NCRP Report No. 160, this category of employment has the highest radiation exposures of any worker group – greater than those in any medical, industrial, nuclear power or any other industry. In all countries in the European Union, since the year 2000. it has been mandatory that all of these personnel receive radiation training and dose assessment as a matter of law. The dose assessment cannot be performed using the type of badges described above because of the complex mix of radiation types and energies present in the in-flight environment. Instead, computer modeling is applied on a route-by-route basis to provide reasonable estimates of the total annual exposure of individual members of this worker group. Our own FAA has a computer program (CARI-6) that can do the calculations for any interested person who wants an estimate of their exposure for a single flight with the input of simple flight information. It can be accessed by anyone at:


    At present, there is no definitive data showing harm from the levels of radiation encountered in-flight, but analysis of health impacts at these levels of exposure is very difficult. Several studies are ongoing with regard to this possible health risk. A wild-card in this discussion is the potential significant increase in radiation levels as a result of certain “solar storms” causing what are called coronal mass ejections, the release of particulate radiation that, if it is directed in the direction of the Earth during the sun’s rotation, can dramatically increase the ordinary radiation levels for brief periods. Our FAA has a radiation warning system that alerts airlines in such circumstances. Usually this results in the diversion of polar flights to lower latitudes since the radiation particles are pulled in to the polar regions by the Earth’s magnetic field and the exposures are higher there than at mid-latitudes. Some carriers take action. Others don’t. See:


    In general, anyone flying more than about 85,000 miles per year on high-altitude trips will receive a radiation exposure greater than would be permitted to a member of the public if such an exposure were to come from a ground-based medical or industrial source. So business frequent flyers are also radiation workers although, notwithstanding efforts of myself and a few others to advance public perception of this issue, as far as I know no employers are providing this information to their frequent-flyer employees. This may be of particular interest to women in early-stage pregnancy because fetal sensitivity to radiation is greater than that of adults

    Robert Barish, PhD
    author: The Invisible Passenger: Radiation Risks for People Who Fly

  • 91StealthES at 10:17am April 17, 2013

    Thank you for the response.

    I find it interesting that you state that body badges and meters cannot be used due to the radiation type and energies present. There are badges and meters designed to access all different forms of radiation. Also, besides gamma and beta, what are you exposed to in-flight?

    To me, if individuals and airlines are worried, it would make sense to have a meter on every plane, as it could be reset after each flight and would allow each employee to maintain a record of their exposure.

    I find it interesting that there is a supposed concern, but only models are used to assess their exposure. It doesn’t make sense. How can a model be used, if you indicate there is no way to measure the level of exposure?

  • robbarish at 5:06am April 19, 2013

    The primary radiation component encountered in an airliner at altitude is neutrons produced by the interaction of solar and galactic charged particles with the Earth’s atmosphere. There are other radiation components as well, in lesser quantities. Measuring neutrons over the wide energy spectrum encountered in flight is problematic but there are instruments that can do so. They are relatively massive but have been used extensively since the late 1980s in making measurements that have served to validate the computer models such as CARI-6, EPCARD, SIEVERT, PCAIRE and other computer programs that are widely used in the European Union and elsewhere. Because aircrew fly their typical routes repeatedly over the course of a year, the European Airlines have decided it makes sense to use average calculated exposures for these routes rather than make individual measurements. And measurements by various scientific groups continue to be made to further refine these models. See for example:


    As a point of interest, the radiation dose rate is very altitude dependent, changing by about a factor of two for every change in altitude of approximately 6,000 feet. So changes in flight altitude have significant impacts for individual trips but tend to average out for the airline personnel whose recordkeeping covers many hundreds of hours in the air each year. I have advocated instrumentation of the sort mentioned above but, to date, no one has passed such equipment through the required FAA engineering protocols necessary before any electronic devices can be placed in an aircraft. And, of course, even if such instrumentation were approved there would have to be an elaborate maintenance and calibration scheme associated with the thousands of units placed in service. Because only carriers outside of the USA require dose assessment, they have chosen the simpler and less expensive option of using the computed values of exposure. Since 1988 I have been trying to influence air carriers in the United States to at least afford their employees with education on this subject, but with very little success. In the financially-challenged airline industry any additional expense is quite uniformly ignored. And this has been the case for more than 25 years, notwithstanding strenuous lobbying on this issue by various flight attendant unions, particularly AFA whose 60,000 members work at more than 20 airlines. I’ve pretty well given up trying even after offering my book to that union for just about the cost of its production.

Leave Reply

You must be a logged in member to post a comment. Click here to Register.