Council on Radiation Protection and Measurements, said in 2010 that millimeter wave scanners are probably within bounds [of standards for safe operation], but there should be an effort to verify that they are safe for frequent use. WHO (World Health Organization) in 2011 categorized RF (radio frequency) radiation as a possible carcinogen. Numerical simulations of terahertz radiation, which active millimeter-wave scanners do not operate at, have produced mixed results. Researchers at the Center for Nonlinear Studies at Los Alamos National Laboratory in New Mexico have used simulations to show a way that terahertz radiation may affect DNA, However, this has not been verified. Backscatter X-ray scanners In the United States, the FAA Modernization and Reform Act of 2012 required that all full-body scanners operated in airports by the Transportation Security Administration use "Automated Target Recognition" software, which replaces the picture of a nude body with the cartoon-like representation. As a result of this law, all backscatter X-ray machines formerly in use by the Transportation Security Administration were removed from airports by May 2013, since the agency said the vendor (Rapiscan) did not meet their contractual deadline to implement the software. In the European Union, backscatter X-ray screening of airline passengers was banned in 2012 to protect passenger safety, and the deployment at Manchester Airport was removed. Several radiation safety authorities including the National Council on Radiation Protection and Measurements, The Health Physics Society, and the American College of Radiology, have stated that they are "not aware of any evidence" that full-body scans are unsafe. However, other radiation authorities, including the International Atomic Energy Agency and Nuclear Energy Agency recommend against using ionizing radiation on certain populations like pregnant women and children, and opponents of the devices say that no long-term studies have been done on the health effects of either backscatter X-ray or millimeter wave scanners: "I don't think the right questions have been asked. We don't have enough information to make a decision on whether there's going to be a biological effect or not". (Douglas Boreham, professor in Medical Physics and Applied Radiation Sciences at McMaster University in Hamilton, Ontario.) Richard Morin, a medical physicist at the Mayo Clinic has said that he is not concerned about health effects from backscatter X-ray scanners: "From a radiation standpoint there has been no evidence that there is really any untoward effect from the use of this device [backscatter scanner], so I