(C) Scientific American

DAEJEON, South Korea — In a landmark international study aimed at addressing long-standing public health concerns, researchers have concluded that long-term exposure to radiofrequency (RF) electromagnetic fields from mobile phones does not increase the risk of developing tumors.

The Electronics and Telecommunications Research Institute (ETRI) announced on Tuesday the results of a large-scale, four-year joint animal study conducted with Japanese researchers. The findings indicate no significant correlation between prolonged cell phone radiation exposure and the occurrence of brain or heart tumors.

Challenging Previous Findings
The study was launched in 2019 to verify controversial findings reported in 2018 by the U.S. National Toxicology Program (NTP). The NTP study had previously suggested an increase in brain and heart tumors among male rats exposed to high levels of 900MHz CDMA radiation.

To ensure scientific rigor, ETRI and their Japanese counterparts established the world’s first integrated cross-border data system for toxicity research. Both nations utilized identical experimental conditions, including the same animal species, feed, and ETRI-designed radiation exposure chambers, following OECD toxicity testing guidelines.

Rigorous Experimental Design
The experiment divided male rats into three groups:

RF Exposure Group: Subjected to 900MHz CDMA radiation at an intensity of 4W/kg (a level used as a baseline for human safety standards).
Sham Group: Placed in the same environment without radiation exposure.
Cage Control Group: Kept in standard laboratory conditions.
The subjects were monitored throughout their entire life cycle—104 weeks—starting from the early stages of pregnancy. This duration is roughly equivalent to a human living to old age while constantly using a mobile device.

Consistent Global Results
The results from both Korea and Japan were remarkably consistent. In the South Korean trials, the incidence of tumors in all groups fell within the range of natural occurrence. No statistically significant differences were found in the heart, brain, or adrenal glands between the exposed and sham groups.

While the Japanese trials showed a slightly higher survival rate in the radiation-exposed group, they similarly found no evidence that radiation triggered or accelerated tumor growth.

"This study is significant because it failed to replicate the tumor increases reported by the NTP at exposure levels that form the basis of our current safety standards," said Professor Ahn Young-hwan of Ajou University School of Medicine. "It should help alleviate excessive public anxiety regarding cell phone radiation."

Looking Toward 5G
The findings are expected to serve as a critical reference for the International Agency for Research on Cancer (IARC) when it re-evaluates the carcinogenicity of RF electromagnetic fields in the future.

Moon Jung-ik, head of the Radio Environment Monitoring Research Section at ETRI, emphasized that the work isn't over. "Having established a standardized protocol for international joint animal studies, we plan to pursue follow-up research to scientifically investigate the effects of complex environments where 4G and 5G coexist."