Feds Disagree on Cell Phone
November 2, 2018
National Toxicology Program (NTP) concluded there is clear evidence
that male rats exposed to high levels of radio frequency radiation (RFR)
like that used in 2G and 3G cell phones developed cancerous heart
tumors, according to final reports released today. There was also
some evidence of tumors in the brain and adrenal gland of exposed
male rats. For female rats, and male and female mice, the evidence
was equivocal as to whether cancers observed were associated with
exposure to RFR. The final reports represent the consensus of NTP
and a panel of external scientific experts who reviewed the studies
in March after draft reports were issued in February.
“The exposures used in the studies cannot be compared directly to
the exposure that humans experience when using a cell phone,” said
John Bucher, Ph.D., NTP senior scientist. “In our studies, rats and
mice received radio frequency radiation across their whole bodies.
By contrast, people are mostly exposed in specific local tissues
close to where they hold the phone. In addition, the exposure levels
and durations in our studies were greater than what people
The lowest exposure level used in the studies was equal to the
maximum local tissue exposure currently allowed for cell phone
users. This power level rarely occurs with typical cell phone use.
The highest exposure level in the studies was four times higher than
the maximum power level permitted.
“We believe that the link between radio frequency radiation and
tumors in male rats is real, and the external experts agreed,” said
The $30 million NTP studies took more than 10 years to complete and
are the most comprehensive assessment, to date, of health effects in
animals exposed to RFR with modulations used in 2G and 3G cell
phones. 2G and 3G networks were standard when the studies were
designed and are still used for phone calls and texting.
“A major strength of our studies is that we were able to control
exactly how much radio frequency radiation the animals received —
something that’s not possible when studying human cell phone use,
which has often relied on questionnaires,” said Michael Wyde, Ph.D.,
lead toxicologist on the studies.
He also noted the unexpected finding of longer lifespans among the
exposed male rats. “This may be explained by an observed decrease in
chronic kidney problems that are often the cause of death in older
rats,” Wyde said.
The animals were housed in chambers specifically designed and built
for these studies. Exposure to RFR began in the womb for rats and at
5 to 6 weeks old for mice, and continued for up to two years, or
most of their natural lifetime. The RFR exposure was intermittent,
10 minutes on and 10 minutes off, totaling about nine hours each
day. RFR levels ranged from 1.5-6 watts per kilogram in rats, and
2.5-10 watts per kilogram in mice.
These studies did not investigate the types of RFR used for Wi-Fi or
“5G is an emerging technology that hasn’t really been defined yet.
From what we currently understand, it likely differs dramatically
from what we studied,” said Wyde.
For future studies, NTP is building smaller RFR exposure chambers
that will make it easier to evaluate newer telecommunications
technologies in weeks or months, rather than years. These studies
will focus on developing measurable physical indicators, or
biomarkers, of potential effects from RFR. These may include changes
in metrics like DNA damage in exposed tissues, which can be detected
much sooner than cancer.
The U.S. Food and Drug Administration nominated cell phone RFR for
study by NTP because of widespread public use of cell phones and
limited knowledge about potential health effects from long-term
exposure. NTP will provide the results of these studies to FDA and
the Federal Communications Commission, who will review the
information as they continue to monitor new research on the
potential effects of RFR.
NTP uses four categories to summarize the evidence that a
substance may cause cancer:
Clear evidence (highest)
Jeffrey Shuren, M.D., J.D.,
Director of the FDA’s Center for Devices and Radiological Health
said, "We know that cell phones are an important, everyday tool to
most Americans. We use them now for much more than just talking—from
booking travel on an app to using mobile wallets to pay for
groceries. Our ubitquitious use of cell phones inevitably means that
we must continue to review and ensure their safety.
The Food and Drug Administration is charged with ensuring cell
phones— and any radiation-emitting electronic product—are safe for
the public to use. Our scientific expertise and input, along with
other health agencies, are used by the Federal Communications
Commission (FCC) to set the standards for exposure limits of
radiation from cell phones, called radiofrequency energy.
We have relied on decades of research and hundreds of studies to
have the most complete evaluation of radiofrequency energy exposure.
This information has informed the FDA’s assessment of this important
public health issue, and given us the confidence that the current
safety limits for cell phone radiofrequency energy exposure remain
acceptable for protecting the public health.
When new studies or information becomes available, the FDA conducts
thorough evaluations of the data to continually inform our thinking.
We reviewed the recently finalized research conducted by our
colleagues at the National Toxicology Program (NTP), part of the
National Institute of Environmental Health Sciences within the
National Institutes of Health, on radiofrequency energy exposure.
After reviewing the study, we disagree, however, with the
conclusions of their final report regarding “clear evidence” of
carcinogenic activity in rodents exposed to radiofrequency energy.
In the NTP study, researchers looked at the effects of exposing
rodents to extremely high levels of radiofrequency throughout the
entire body. This is commonly done in these types of hazard
identification studies and means that the study tested levels of
radiofrequency energy exposures considerably above the current whole
body safety limits for cell phones. Doing this was intended to help
contribute to what we already understand about the effects of
radiofrequency energy on animal tissue. In fact, we only begin to
observe effects to animal tissue at exposures that are 50 times
higher than the current whole body safety limits set by the FCC for
radiofrequency energy exposure.
Our colleagues at NTP echoed this point in a statement earlier this
year about their draft final report, including the important note
that “these findings should not be directly extrapolated to human
cell phone usage.”
We agree that these findings should not be applied to human cell
NTP hosted a three-day peer review of this study in March, as part
of their normal process for issuing scientific reports. The FDA was
not a participant in that process, but was invited to observe the
panel discussions, which included an assessment of the study methods
and data by a panel of 15 peer reviewers to determine the basis of
evidence for the final report. Based on their assessment, the panel
voted to upgrade the conclusions from some evidence to clear
evidence for malignant heart schwannomas in male rats, and from
equivocal (ambigious) to some evidence for malignant gliomas of the
brain and benign tumors of the adrenal gland in male rats. It’s
important to note that the vote does not mean new data or findings
were reported in the final assessment.
In addition, as we’ve noted previously, there were unusual findings
in the study, such as: the rats exposed to whole body radiofrequency
energy lived longer than rats that were not exposed to any radiation
(control group); only male rats exposed to the highest
radiofrequency energy dosage developed a statistically significant
number of heart schwannomas, which are very rare in humans, when
compared to the control group in this experiment. There was also no
true dose response, or a lack of a clear relationship between the
doses of radiation administered to the animals and their subsequent
tumor rate. Researchers will need to consider all of the findings
when exploring future human epidemiological studies.
As scientists, we welcome new studies. Animal studies like this one
contribute to our discussions on this topic, but we must remember
the study was not designed to test the safety of cell phone use in
humans, so we cannot draw conclusions about the risks of cell phone
use from it. We also must thoroughly evaluate and take into
consideration the totality of the data, and do so within the context
of the complete body of evidence rather than drawing conclusions
from the results of a single study.
part of our commitment to protecting the public health, the FDA has
reviewed, and will continue to review, many sources of scientific
and medical evidence related to the possibility of adverse health
effects from radiofrequency energy exposure in both humans and
animals and will continue to do so as new scientific data are
Based on our ongoing evaluation of this issue, the totality of the
available scientific evidence continues to not support adverse
health effects in humans caused by exposures at or under the current
radiofrequency energy exposure limits. We believe the existing
safety limits for cell phones remain acceptable for protecting the
The FDA, an agency within the U.S. Department of Health and Human
Services, protects the public health by assuring the safety,
effectiveness, and security of human and veterinary drugs, vaccines
and other biological products for human use, and medical devices.
The agency also is responsible for the safety and security of our
nation’s food supply, cosmetics, dietary supplements, products that
give off electronic radiation, and for regulating tobacco products."