cell phones, mobile devices

Do cell phones cause cancer? A new study has found a troubling link.

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A major new U.S. government study says cell phones may cause cancer, reigniting years of debate over the long-term health effects of mobile devices.

The National Toxicology Program (NTP) announced late Thursday that a multi-year, peer-reviewed study found "low incidences" of two kinds of tumors in rats exposed to radio frequencies produced by cell phones. The Wall Street Journal reports the tumors were gliomas, which are in the glial cells of the brain, and schwannomas of the heart.

"Given the widespread global usage of mobile communications among users of all ages, even a very small increase in the incidence of disease resulting from exposure to [radio-frequency radiation] could have broad implications for public health," the findings said.

Yahoo! News reports the study, which cost $25 million for more than a decade of research, is the NTP's most expensive project ever. More than 2,500 rodents were exposed to the same type of radiation and frequencies used by cell phones for nine hours daily for two years.

The cancer link was only found in male rats, though rats exposed in utero tended to have slightly lower birth weights. Results from the research on mice weren't released.

The findings appear to support earlier research that found the same types of tumors in humans, causing the International Agency for Research on Cancer to classify radiation as a possible human carcinogen, back in 2011.The World Health Organization also said that year that cellphone radiation was considered a group 2B possible carcinogen.

"This study in mice and rats is under review by additional experts," a spokesperson for the National Institutes of Health (NIH), which oversaw the new study, said in a statement. "It is important to note that previous human, observational data collected in earlier, large-scale population-based studies have found limited evidence of an increased risk for developing cancer from cell phone use."

Industry leaders, on the other hand, have insisted there are no dangers in using cell phones or other mobile devices. The WSJ points out some pickled vegetables and coffee are also considered to be possibly carcinogenic by the WHO and the IARC.

Earlier this month, results from a 30-year study in Australia found no significant link between cell phones and brain cancer among humans despite an increase in mobile devices. Cancer rates rose slightly in men since 1993, but remained stable in women.

But Ron Melnick, who ran the NTP project until retiring in 2009, told the newspaper that the their results should put an end to people saying there's no risk.

The Federal Communications Commission, which determines safety guidelines for U.S. cellphone use, told the WSJ that no changes have been suggested to the public yet.

"Scientific evidence always informs FCC rules on this matter," an FCC spokesman said. "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."