For a decade now, the potential health risks of mobile phone use and more generally, exposure to radiofrequencies have been a very controversial subject. The core of this debate is our uncertainly about the risks entailed by ubiquitous but low-level exposure to the electromagnetic spectrum emitted by telecommunication technologies. The analysis of the health risks from this kind of exposure is very complex; and it divides experts and activists, and even experts among themselves. This paper, which adopts simultaneously a historical and epistemological perspective, shows that this controversy highlights the complexity and ambivalence of how we deal with the uncertainty of environmental risks. The analysis of the institutional and political responses to this debate in France shows the shifts in expert opinion that have followed it. This paper argues that it is essential to reevaluate our view on the links between science and uncertainty if we are to overcome some of the challenges of this kind of controversy.