An interview between Joi Iti, Sean Bonner and Pieter Franken, the co-founders of Safecast, a citizen science organisation that formed in response to Fukushima nuclear disaster. At the time of the disaster, information on local radiation level was scarce, but their organisation combined a crowd-sourcing approach with cutting edge and easily sourced technology to quickly begin monitoring, collecting, and openly sharing information on environmental radiation.This interview was originally recorded for Joi's conversations podcast (https://joi.ito.com/weblog/2016/12/24/safecast-conver.html) and is used here under Creative Commons licence 4.0Image is screenshot of Safecast.org's map of Eastern Japan, that shows heightened radiation levels around Fukushima (the red and yellow areas).