This report contains the results and process of the National Research Council Committee to Assess the Potential Health Effects from Exposure to PAVE PAWS Low-Level Phased-Array Radiofrequency Energy. The PAVE PAWS radar system is located on Cape Cod, Massachusetts—near several populated residential areas and in a region known for its scenic beauty and ecological richness as well as being a popular tourist area. The purpose of this section is to describe the history of the facility and, in particular, the history of public concerns that have led to the committee’s charge as well as to a number of other studies and investigations.
While the committee was established to perform an independent assessment of the possible biological and potential health effects of the PAVE PAWS phased-array radar system, and has a very specific statement of work (see below), the committee has taken very seriously the genesis for this study and, in particular, the specific concerns expressed by some members of the public.
HISTORY OF THE FACILITY
The PAVE PAWS phased-array radar system on Cape Cod was first conceived by the Joint Chiefs of Staff in 1972. The Raytheon Company was selected as the primary contractor on April 12, 1976, to build the facility. On March 17, 1976, the Air Force issued an environmental assessment of the PAVE PAWS radar system. For the purposes of that assessment, a power desity of 10 milliwatts per square centimeter (mW/cm2) as averaged over any 6-minute period was established as a guideline for limiting occupational exposure. This guideline was provided by the U.S. Air Force School of Aerospace Medicine on
the basis of existing Occupational Safety and Health Administration guidelines. In understanding the history of the community’s concerns, it is important to note that these guidelines were not specified for non-occupational, continuous exposure. The Air Force’s assessment considered a number of potentially detrimental scenarios to the environment due to the construction and operation of the radar and judged the impact to be minimal. It also noted considerations that were thought to offset the identified potential adverse environmental effects. The Air Force Environmental Assessment concluded in part that the proposed installation and operation of PAVE PAWS “is not a major federal action with significant adverse impact on the quality of the human environment.” A report was also issued by a Department of Defense contractor, the Illinois Institute of Technology Research Institute, in May of 1976 that evaluated the impact of the proposed PAVE PAWS radar system on the electromagnetic environment at and near the proposed facility (IITRI 1976). Subsequently, on December 22, 1977, the Environmental Protection Agency (EPA) issued an environmental impact analysis of the PAVE PAWS system at the request of Massachusetts Representative Gerry E. Studds. For locations selected for evaluation that were beyond the boundaries of Otis AFB, the report concluded that “the predicted values of time-averaged power density are considered to be well below values that should have any health impact.”
Following those studies, the Cape Cod Environmental Coalition, Inc. (CCEC), a citizens group, undertook court action in the U.S. District Court against various Air Force officials on March 3, 1978. The suit contended that the PAVE PAWS project was in violation of the National Environmental Policy Act of 1969 because an Environmental Impact Statement (EIS) had not been prepared. On October 31, 1978, the CCEC and the Air Force entered into an agreement temporarily suspending further litigation brought by the citizens group. Under the agreement, the Air Force was allowed to continue construction of the facility while it completed an EIS. The EIS was prepared by Stanford Research International under a contract with the Air Force in May of 1979.
Prior to completion of the EIS, the Air Force asked the National Academy of Sciences to perform two studies relevant to the EIS. One study was to focus on the safety measures inherent in the engineering design of the radar system and the second study was to focus on the extent of human exposure from the radar. These studies were completed in 1979. The results from the studies concluded that the “PAVE PAWS system may be anticipated to expose a limited number of members of the general public intermittently to low intensities of pulse-modulated microwave fields with maximal instantaneous intensities of 100 µW/cm2 or less and time-averaged intensities lower by two orders of magnitude. There are no known irreversible effects of such exposure on either morbidity or mortality in humans or other species. Thus it is improbable that exposure will present any hazard to the public.” However, the report went on to add, “In view of the known sensitivity of the mammalian central nervous system to electromagnetic fields,
especially those modulated at brainwave frequencies, the possibility cannot be ruled out that exposure to PAVE PAWS radiation may have some effects on exposed people. Because these effects are still hypothetical, it is not feasible to assess their health implications. Such assessment will require additional research and surveillance and must be addressed in future evaluations of the potential exposure effects of PAVE PAWS and other high-power-output radar systems.” Finally, the report recommended that additional research be conducted to clarify the possible effects of long-term exposure to the radar system. It is this recommendation that has formed the basis, in part, for some of the concerns expressed in the intervening 23 years by some local citizens prior to the start of this committee’s current study.
Some of the concerns voiced by the public at the time of the 1979 study included concerns about possible thermal effects, disruption of implanted medical devices (such as pacemakers), and secondary radiation effects from improperly grounded structures exposed to the radar. In recent years, public concerns have shifted away from thermal effects of RF energy emitted by the radar and have centered on theories that relate to the waveform of the phased-array radar and concerns over the possible health ramifications from the propagation of the RF energy in tissue. A number of hypotheses have been advanced that propose possible mechanisms for health effects. In particular, some community members have made mention of studies done, and possible mechanisms of action advanced, by Dr. Richard Albanes.1
Dr. Albanese’s concerns include potential biological effects on cells and tissues from:
“Steep” rise-times in the PAVE-PAWS waveform,
Overlapping wave fronts originating from multiple antennas on the PAVE PAWS radar, and
The possibility of precursor formation in tissue.
Public concern over the potential for health effects from PAVE PAWS have been heightened by the Massachusetts Department of Public Health Cancer Registry reports, which for the last 10-plus years have reported on several excess cancers in the Cape Cod area, and, for certain cancers, on the upper Cape. Chapter 9 includes a summary and review of the available health studies and cancer registry information. Concern over the potential excess in cancers has been linked, for some members of the public, to potential environmental sources including PAVE PAWS.
Citizens expressed further concern over the PAVE PAWS radar system when
the Air Force announced in 1999 its proposed plans to upgrade the PAVE PAWS system. The Air Force has noted that the upgrades only involve system upgrades and do not involve physical expansion of the system. Following the Air Force’s proposal, the Sandwich Board of Selectman and Senator Kennedy called for a site-specific EIS. The Sandwich Board of Selectman also requested that the Air Force perform laboratory studies of the effects of long-term exposure to PAVE PAWS and that a retrospective epidemiological study be done on Cape Cod to investigate the elevated cancer rates.
Since the time of this committee’s inception, there have been citizens stating concerns on behalf of at least some members of the public about the absence of phased- array site-specific measurement data on PAVE PAWS from the Air Force for the past 23-plus years. That lack of data and failure to follow through on the recommendation made in the original NRC report have appeared to heighten the public’s generalized concern and, for some, resulted in severe distrust of the Air Force. One such citizen’s group is the Coalition for the Operation of PAVE PAWS Safely (COPPS). There has also been concern expressed by some members of the public that the group currently tasked with recommending and overseeing health or epidemiological studies—the local PAVE PAWS Public Health Steering Group (PPPHSG)—is not totally objective or independent of the Air Force, and thus, might not wholly represent some of the citizens who have been expressing concern. Distrust has been further elevated by a concern over potential information contained in the classified Air Force Environmental Health and Safety (EHS) program to which citizens requested that the current NRC committee be provided access. The committee’s review of the EHS program and the committee’s evaluation of the classified information are contained in Chapter 2 of this report.
Although laboratory studies of the effects of long-term exposure to PAVE PAWS waveforms have not been done, a retrospective epidemiological study and supporting power-density analysis have been commissioned by the PPPHSG. The power-density study was completed in May of 2004 and this committee anticipates an NRC review of the epidemiological study when it is completed in 2005. The committee’s evaluation of the PPPHSG power-density study appears in Chapter 4 (Exposure Levels).
In summary, there are members of the Cape Cod public who have had long-standing concern over the potential health effects of the PAVE PAWS radar system. The absence of measured data and further specific studies since the facility was constructed and became operational have increased concerns and frustrated many residents.
ORIGIN OF PRESENT STUDY
In a January 11, 2001, letter from Senator Edward M. Kennedy to the Secretary of the Air Force, F. Whitten Peters, Kennedy asked that the Air Force fund an independent study through the National Research Council of the National Acad-
emies “to examine the health effects of the PAVE PAWS system.” Kennedy further requested that this follow-on study (to the previous 1979 report) should address, at a minimum, the effects, if any, of the PAVE PAWS radar over the past two decades and should also examine the validity of using continuous-wave and pulsed non-ionizing radiation biological-effects data as surrogates for phased-array non-ionizing radiation biological-effects data. The following Statement of Task evolved out of discussions between the Massachusetts congressional delegation (Senators Kennedy and Kerry, and Congressman Delehunt), the Air Force, and the National Academies.
STATEMENT OF TASK
The committee will first determine whether continuous and pulsed radiofrequency (RF) energy research data are adequate for determining the biological and potential health effects of the PAVE PAWS phased-array system. This determination will be communicated to the sponsor as a letter report. If the research data from continuous and pulsed RF energies are considered to be applicable for the determination of possible health effects of phased-array RF energy, the committee will use this information to update the 1979 National Research Council analysis of the exposure levels and potential biological effects of the PAVE PAWS Radar System. If the data are not applicable, the committee will use other information that it determines to be relevant to phased-array health effects to update the 1979 report. In this update the committee will evaluate potential biological and health effects, evaluate exposures of the public to electromagnetic energy from the PAVE PAWS system, and make recommendations for the need for, and focus of, additional scientific studies to address continued scientific uncertainty related to health outcomes and exposure to low-level radiofrequency energy emitted by the PAVE PAWS Radar System. At the completion of its work, the committee will provide an update of the 1979 Research Council report that includes a discussion of:
The applicability of, and the level of uncertainty associated with, using data derived from cell, animal, and epidemiological studies employing continuous-wave exposure for evaluation of potential adverse health effects following phased-array exposures;
The extent of the exposure of the public to electromagnetic energy from the PAVE PAWS system;
Potential biological and health effects of the PAVE PAWS Radar System; and
Recommendations for appropriate follow-on study-design issues, including the strengths and limitations of the approaches suggested and the potential value of the proposed work.
Within the above specific scope, the committee has reviewed the information provided to us by members of the public, outside scientists, and the Air Force. The committee’s scientific review process and deliberations in carrying out the statement of task have been performed with the highest level of scientific and professional integrity. It was also our intent that the process we used be made as transparent as possible. Furthermore, the draft report went through a rigorous independent peer review before the National Academies approved its issuance. The peer reviewers were anonymous to the committee until publication and the committee was required to respond to the satisfaction of the National Academies Report Review Committee before the draft was approved for release as a report of the National Academies. It is extremely difficult, if not impossible, to prove safety—it is, however, possible to examine whether there is a reasonable degree of certainty regarding the presence or absence of harm. In carrying out our statement of work and writing this report, the committee has attempted to evaluate the best available science and used this information and evaluation to address the public’s concerns.
INFORMATION AVAILABLE TO THIS COMMITTEE
A large body of information on radiofrequency effects was available to this committee including RF information databases and recent reviews such as AGNIR (2001, 2003), Boice and McLaughlin (2002), GAO (2001), HCN (2000, 2002, 2003), ICNIRP 2001), Krewski and others (2001a, 2001b), NCRP (2002), NRPB (2004), SSI (2003), and Zmirou (2001). In addition to these databases and reviews, the committee had access to personal libraries accumulated during years of research by committee members on this and related subjects. To evaluate information the committee felt was most relevant to the PAVE PAWS issue, a table was constructed to focus the literature review on those components that the committee felt would be most useful to the present study. That table of criteria was published in a letter report delivered to the Air Force on November 15, 2002, and is included in this report as Appendix A.
Secondly, the Air Force made a PAVE PAWS waveform study available to the committee (AFRL 2003) and the PAVE PAWS Public Health Steering Group made a PAVE PAWS power-density study available to the committee through their contractor, Broadcast Signal Laboratories (BSL 2004).
Finally, a large amount of information was made available to the committee by citizens and other individuals interested in the Academies PAVE PAWS study.
UNCERTAINTIES ASSOCIATED WITH THE EVALUATION OF PAVE PAWS HEALTH EFFECTS
The Statement of Task asks the committee to discuss the level of uncertainty associated with using data derived from cell, animal, and epidemiological studies
employing continuous-wave exposure for evaluation of potential adverse health effects following phased-array exposures. Some of the uncertainties associated with using data derived from studies employing continuous-wave or pulsed-wave exposure for evaluation of potential adverse health effects following phased-array exposures include:
The extent to which pulse shape, repetition rate, and carrier frequency affect biological systems;
The extent to which power levels and exposure duration for a given waveform affect biological systems; and
Identification of the relevant biological effects and how they relate to health outcomes, including the state of the biological system and the pathways by which biological changes occur. Biological test systems may not closely approximate the physiological state in humans, and human physiological conditions vary widely. The approaches to extrapolate from biological effects to health effects are frequently not well defined.
The committee emphasizes that uncertainties are associated with all scientific information and analyses and these uncertainties and others were taken into account in reaching the committee’s conclusions and recommendations.
AFRL (The Air Force Research Laboratory). 2003. Phase IV—Time-domain Waveform Characterization Measurements of the PAVE PAWS Radar. Air Force Research Laboratory, Kirtland Air Force Base, Albuquerque, NM.
AGNIR (Advisory Group on Non-Ionising Radiation). 2001. Possible Health Effects from Terrestrial Trunked Radio (TETRA). Report of an Advisory Group on Non-ionising Radiation. Docs NRPB, (12)2 1-53. Available from http://www.nrpb.org/publications/documents_of_nrpb/abstracts/absd12-2.htm.
AGNIR. 2003. Health Effects from Radiofrequency Electromagnetic Fields. Report of an independent Advisory Group on Non-ionising Radiation. Docs NRPB, 14 1-177. Available from http://www.nrpb.org/publications/documents_of_nrpb/abstracts/absd12-4.htm.
Boice, J.D. and J.K. McLaughlin. 2002. Epidemiologic Studies of Cellular Telephones and Cancer Risk—A Review. SSI Report 2002:16. Stockholm: Statens Strålskyddsinstitut. Available from http://www.ssi.se/english/Press_release_rapp2001_16.html.
BSL (Broadcast Signal Lab). 2004. A Survey of Radio Frequency Energy Field Emissions from the Cape Cod Air Force Station PAVE PAWS Radar Facility: Final Test Report, prepared for PAVE PAWS Public Health Steering Group by Broadcast Signal Lab, Medfield MA.
GAO (General Acct. Office). 2001. Telecommunications: Research and Regulatory Efforts on Mobile Phone Health Issues. Report to Congressional Requesters. GAO-01-545. Washington DC: United States General Accounting Office. Available from http://www.gao.gov/new.items/d01545.pdf.
HCN (Health Council of the Netherlands). 2000. Electromagnetic Fields Committee. GSM Base Stations. Publication Number 2000/16E. The Hague: Health Council of the Netherlands.
HCN. 2002. Electromagnetic Fields Committee. Mobile Telephones: An Evaluation of Health Effects. Publication Number 2002/01E. The Hague: Health Council of the Netherlands.
HCN. 2003. Health Effects of Exposure to Radiofrequency Electromagnetic Fields: Recommendations for Research. Publication Number 2003/03. The Hague: Health Council of the Netherlands.
ICNIRP (International Commission on Non-ionizing Radiation Protection). 2001. Biological Effects, Health Consequences and Standards for Pulsed Radiofrequency Fields in Proceedings of the International Seminar on Biological Effects, Health Consequences and Standards for Pulsed Radiofrequency Fields, Erice, Italy, November 21-25, 1999, R. Matthes, J.H. Bernhardt, and M.H. Repacholi eds. International Commission on Non-ionizing Radiation Protection ISBN 3934994008.
IITRI (Illinois Institute of Technology Research Institute). 1976. EMC Analysis of Otis AFB PAVE PAWS Site. Electromagnetic Compatibiliy Analysis Center ECAC-PR-76-020, Annapolis, MD.
Krewski, D., C.V. Byus, B.W. Glickman, W.G. Lotz, R. Mandeville, M.L. McBride, F.S. Prato, and D.F. Weaver. 2001a. Potential health risks of radiofrequency fields from wireless telecommunication devices. J Toxicol Env Heal B 4:1-143.
Krewski, D., C.V. Byus, B.W. Glickman, W.G. Lotz, R. Mandeville, M.L. McBride, F.S. Prato, and D.F. Weaver. 2001b. Recent advances in research on radiofrequency fields and health. J Toxicol Env Heal B 4:145-159.
NCRP (National Council on Radiation Protection and Measurements). 2002. Biological Effects of Modulated Radiofrequency Fields. NRCP Commentary No 18. Bethesda, Maryland: National Council on Radiation Protection and Measurements.
NRC (National Research Council). 1979. Analysis of the Exposure Levels and Potential Biologic Effects of the PAVE PAWS Radar System. Washington, DC: National Academy Press.
NRPB (National Radiological Protection Board). 2004. Review of the Scientific Evidence for Limiting Exposure to Electromagnetic Fields (0-300 GHz). Docs NRPB 15 (3) 1-215. Available from http://www.nrpb.org/publications/documents_of_nrpb/abstracts/absd15-3.htm.
SSI (Swedish Radiation Protection Institute). 2003. Recent Research on Mobile Telephony and Cancer and Other Selected Biological Effects: First Annual Report from SSI’s Independent Expert Group on Electromagnetic Fields. Available from http://www.ssi.se/english/EMF_exp_Eng_2003.pdf.
Zmirou, D. 2001. Mobile Phones, Their Base Stations, and Health. Report to the French Health Directorate. France, Direction Générale de la Santé. Available from http://www.sante.gouv.fr. Summary in English available from http://www.sante.gouv.fr/htm/dossiers/telephon_mobil/pdf/teleph_uk.doc.