Assessment of health risks related to use of the ProVision 100
Following the attempted attack on a flight between Amsterdam and Detroit on 25 December 2009, the French Interior Security Council decided, for the purpose of reinforcing civil aviation security, to rapidly deploy more powerful imaging equipment than the metal detectors currently being used in French airports.
Given that the instrument being considered for use in French airports is a ProVision 100 body scanner using waves within the 24 - 30 GHz frequency band, the collective expertise report only looked at this model.
On 19 January 2010, AFSSET received a solicited request from the French Ministry of Ecology, Energy, Sustainable Development and the Sea, responsible for environmentally-friendly technologies and negotiations on climate issues, to fill knowledge gaps concerning the health risks associated with the use of so-called "millimetre-wave" body scanners, such as the ProVision 100, in airports.
Working method
Considering the deadline for responding to the solicited request, it was dealt with in accordance with the urgent requests procedure approved by AFSSET and its funding ministries (Health, Ecology and Work).
AFSSET called upon five expert rapporteurs to contribute to the requested expert appraisal. These experts were either members of the Committee of Specialised Experts on "physical agents, new technologies and major developments" or had previously been members of working groups studying electromagnetic fields. This expert appraisal is therefore the result of the work of a group of experts with complementary competences that validated its contents during a telephone conference on 11 February 2010. The expert appraisal was carried out in compliance with French standard NFX50-110 "Quality in expert appraisal activities - general requirements of competence for expert appraisals (May 2003)" in order to meet the following criteria: competence, independence, transparency and traceability.
To carry out their work, the experts used scientific and technical data available in the literature on body scanners, namely those issued by the French Civil Aviation Technical Department (STAC), and also the results of available measurements.
Summary of the expert appraisal
The ProVision 100 is a body scanner which allows "whole body" images of people to be taken for security purposes without exposing them to ionizing radiation, the claimed advantages being the scanner's reliability and reduced intrusiveness when compared to pat-down searches. Its technology is based on the use of so-called "millimetre" waves, found within the 24 - 30 GHz frequency band.
Assessment of the exposure of individuals to electromagnetic fields during a scan
The power densities measured during a scan are extremely low, of the order of a few tens to a few hundred microwatts per square meter (347 µW/m² according to a measurement report issued by Apave [1], 640 µW/m² according to measurements made by the Emitech laboratory and 59.7 µW/m² according to TSA1. The measurements carried out by French laboratories did not allow accurate characterisation of the electromagnetic field inside the scanner, mainly due to the extremely low signal intensities and also the metrological complexity required. It should be noted that there is no Cofrac accreditation in France for carrying out measurements in the frequency band used by this piece of equipment. To obtain reliable results from measurements taken of the signals emitted, the metrology would need to be more precise.
The exposure of individuals to electromagnetic fields during a scan is very short and does not exceed 2 seconds.
The data collected from the manufacturers of the scanner and from measurement reports provided by the STAC indicate that the exposure of individuals to electromagnetic fields produced by ProVision 100 body scanners is well below that prescribed in current regulations (Decree No. 2002-775 of 3 May 2002).
Assessment of the health risks associated with the use of the ProVision 100 body scanner
The skin is the main area of bodily interaction with the so-called "millimeter" waves. Notably, due to their low wavelength, they will only penetrate the body to a very shallow depth. Their interaction with living matter is essentially associated with the absorption of energy by free water in superficial skin tissues, which could potentially lead to biological effects for higher surface power densities.
Under normal operating conditions, a "millimeter" wave body scanner of the ProVision 100 type operates with surface power densities well below those required (in the order of 1,000 W/m²) to induce tissue heating. Thus, no thermal effect on exposed tissue is expected following a scan.
Many in vitro studies suggest the existence of potential biological effects from "millimeter" waves, especially on membrane rich organelles or even on ion exchanges. Certain results obtained are leading to ideas that the synthesis and secretion of proteins could be altered and/or favoured. However, these effects were observed for surface power densities well above those emitted by the ProVision 100. Currently, no mechanism of wave-cell interaction has been identified for the frequency band concerned (24 - 30 GHz).
Based on current knowledge, there is no known health effect associated with exposure to electromagnetic fields for this frequency range and the surface power densities used by the ProVision 100 device. Nevertheless the health effects of this frequency range are still less documented, and it is not possible to make any extrapolations based on data from higher densities.
In addition, due to improvements in electromagnetic compatibility with implanted medical devices (such as pacemakers for example) on one hand, and the depth of where these devices are found (not accessible to "millimeter" waves) on the other, no significant incompatibility issues have been identified with using the ProVision 100 scanner.
Conclusions
From the point of view of regulations concerning the exposure of individuals to electromagnetic fields, the values measured for the ProVision 100 "millimeter" wave body scanner are well below those detailed in Decree No. 2002-775 [4] (for the frequencies considered, the average surface power density over a 2 minute period must be less than 10 W/m²).
Furthermore, based on current knowledge regarding the health effects of "millimeter" waves, and on the basis of technical information gathered on the ProVision 100 device, there are no proven health risks to individuals from exposure to electromagnetic fields within the 24 - 30 GHz frequency range shown for this type of scanner.
Recommendations
With regard to the implementation of detection equipment in French airports
the Agency recommends:
continuing with the gathering of information relating to the implementation of passive technologies, for example, and the study of their performance and their potential implementation with regard to so called "millimeter" techniques.
With regard to guaranteeing the compliance and safety of "millimeter" wave body scanners
In order to guarantee that these instruments function correctly and also to ensure low levels of public exposure, the Agency recommends:
With regard to the characterisation of the exposure of individuals
In order to improve the metrology of "millimeter" waves emitted by body scanners, the Agency recommends:
With regard to the studies and research into the biological and health effects of "millimeter" waves
In order to gain scientific knowledge of the potential effects from "millimeter" waves, the Agency recommends:
With regard to information for the public and the users of the detection devices
In order to guarantee good public information, the Agency recommends:
Moreover, the Agency also recommends:
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Note relating to the "ProVision 100 "millimeter" wave body scanner" 
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