Federal regulators have maintained that cellphones pose no danger. But a growing body of scientific research is raising questions, with the stakes heightened by the ongoing deployment of hundreds of thousands of new transmitters in neighborhoods across America. ProPublica recently examined the issue in detail, finding that the chief government regulator, the Federal Communications Commission, relies on an exposure standard from 1996 ... and that the agency brushed aside a lengthy study by a different arm of the federal government that found that cellphone radiation caused rare cancers. The newest generation of cellphone technology, known as 5G, remains largely untested. A growing body of research has found evidence of health risks even when people are exposed to radiation below the FCC limits. The array of possible harms ranges from effects on fertility and fetal development to associations with cancer. Some studies of people living near cell towers have also confirmed an array of health complaints, including dizziness, nausea, headaches, tinnitus and insomnia. In 2011, the International Agency for Research on Cancer, an arm of the World Health Organization, cited troubling but uncertain evidence in classifying wireless radiation as "possibly carcinogenic to humans." In 2018, a study by the federal government that was nearly two decades in the making found "clear evidence" that cellphone radiation caused cancer in lab animals.