(Wall Street Journal) — Using a cellphone may increase the risk of a certain type of brain cancer, an international panel of experts said Tuesday, adding to a growing debate about whether a now nearly ubiquitous form of communication poses health risks. The experts said cellphone radio waves are “possibly carcinogenic,” classifying them in the same risk category as lead, chloroform and coffee. The classification from the World Health Organization’s International Agency for Research on Cancer could lead the United Nations health body to look again at its mobile-phone guidelines, the scientists said. The IARC panel did not conduct new research. Its findings, which will be published July 1 in the journal Lancet Oncology and in a few days online, came after reviewing the “available literature” on everything from microwave exposure to the environmental exposures of radio, television and wireless signals.