Americans are being bombarded" with chemicals, gases and radiation that can cause cancer, and the federal government must do far more to protect them, presidential cancer advisers said. The panel said many avoidable cancers were also caused by pollution, radon from the soil and medical imaging scans. Since so little is known about the possible risks of cell phones, people would be prudent to wear headsets and make calls quickly ... the panel advised. "The panel was particularly concerned to find that the true burden of environmentally induced cancer has been grossly underestimated," they wrote in the report. It is the first time the panel has taken such a sharp turn into what had long been disputed territory - whether pollution, cell phones and even household objects, such as water bottles, can cause cancer. Cancer is the No. 2 killer of Americans, after heart disease. "The incidence of some cancers, including some most common among children, is increasing for unexplained reasons," the report reads. "With nearly 80,000 chemicals on the market in the United States, many of which are used by millions of Americans in their daily lives and are un- or understudied and largely unregulated, exposure to potential environmental carcinogens is widespread," it adds.