In 2005 the Salzburg Medical Director of Public Health, Dr. Gerd Oberfeld sent a letter to all schools in Salzburg warning against the danger of Wi-Fi in schools.  In the same year Professor Olle Johansson, a neuroscientist at the Karolinska Institute in Sweden also sent out a letter to concerned parents quoting research showing the link between radio frequency radiation and health effects  . Four years later in 2009 Dr. Magda Havas, an Environmental toxicologist at Toronto University, Canada, sent a letter to all School Principals and School Boards in Canada warning against the use of Wi-Fi in schools on health grounds . An up-dated version of this letter was sent to those holding positions of responsibility in the education sector again in May 2012 .
Adding weight to the gravitas of this issue, in March 2013, The Executive Committee of the American Academy of Environmental Medicine urged the Los Angeles Unified School District, when considering its proposal to install Wi-Fi in Los Angeles, to opt instead for hardwired internet connections due to the uncertain risks Wi-Fi technology poses – its health risks for children being first on its list .