A new U.S. government report will undoubtedly revive the debate as to whether or not cellphones cause cancer. The findings revealed low rates of two types of tumors — gliomas, in the brain, and schwannomas, in the heart — were discovered in rats that had been exposed to radio frequencies emitted by cellphones.

The two-year peer-reviewed study was conducted by the National Toxicology Program. In it, more than 2,500 rats and mice were exposed to GSM and CDMA radio frequencies (900Mhz for rats and 1900 Mhz for mice) each day for 18 hours — 10 minutes on, followed by 10 minutes off. Cancer was discovered only in male rats, and those exposed while in utero tended to show lower birth weights.

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When asked for comment, Neil Grace, the senior communications advisor for the FCC, wrote this response: "We are aware that the National Toxicology Program is studying this important issue. Scientific evidence always informs FCC rules on this matter. We will continue to follow all recommendations from federal health and safety experts including whether the FCC should modify its current policies and RF exposure limits.”

Previous studies by various agencies and organizations have produced contradictory results. One such study, published in the peer-reviewed Environmental Health Perspectives Journal in 2011 found no connection, while another study the same year by the World Health Organization categorized cellphones as "possibly carcinogenic to humans," and grouped it in the same category as lead, gasoline fumes and the pesticide DDT.

Only partial results of the most recent program were released yesterday (May 26); the full report will be released in the fall of 2017.

The CTIA released the following statement: "CTIA and the wireless industry note the release of the National Toxicology Program partial findings, and are still reviewing those findings. The larger scientific community will consider the partial findings, as well as the complete reports, in the context of the many other scientific studies conducted over several decades."

"Numerous international and U.S. organizations, including the U.S. Food and Drug Administration, World Health Organization, and American Cancer Society, have determined that the already existing body of peer-reviewed and published studies shows that there are no established health effects from radio frequency signals used in cellphones. The evidence includes official federal brain cancer statistics showing that since the introduction of cellphones in the mid-1980s, the rate of brain cancer in the United States has remained stable.”