{{Short description|Environmental monitoring organization}} {{Use dmy dates|date=April 2026}} {{Infobox organization | name = Safecast | logo = Safecast.org logo boxed version.svg | founded = {{start date and age|2011}} | founders = Sean Bonner, Joi Ito, Pieter Franken | location = Dogenzaka, Shibuya, Tokyo, Japan | focus = Citizen science, environmental monitoring, open data | method = Volunteer data collection, open hardware, open data | website = {{URL|https://safecast.org/}} }}
'''Safecast''' is an international volunteer-driven nonprofit organization focused on citizen science and environmental monitoring. Founded in 2011 in the aftermath of the Fukushima Daiichi nuclear disaster, it is best known for collecting and publishing open radiation data and for developing community-based environmental sensing projects.<ref>{{cite web |title=About |url=https://safecast.org/about/ |website=Safecast |access-date=8 April 2026}}</ref><ref>{{cite web |title=History of Safecast |url=https://safecast.org/history-of-safecast/ |website=Safecast |access-date=8 April 2026}}</ref><ref>{{cite journal |last1=Brown |first1=Azby |last2=Franken |first2=Pieter |last3=Bonner |first3=Sean |last4=Dolezal |first4=Nick |last5=Moross |first5=Joe |title=Safecast: successful citizen-science for radiation measurement and communication after Fukushima |journal=Journal of Radiological Protection |date=2016 |volume=36 |issue=2 |pages=S82–S101 |doi=10.1088/0952-4746/36/2/S82 |pmid=27270965 |bibcode=2016JRP....36S..82B |doi-access=free}}</ref>
Safecast publishes its measurements as open data under a CC0 public-domain dedication and makes them available through a public API and interactive map.<ref>{{cite web |title=About |url=https://safecast.org/about/ |website=Safecast |access-date=8 April 2026}}</ref><ref>{{cite web |title=Data |url=https://safecast.org/data/ |website=Safecast |access-date=8 April 2026}}</ref><ref>{{cite web |title=Safecast Map |url=https://map.safecast.org/ |website=Safecast |access-date=8 April 2026}}</ref> Its data and methods have been discussed in both scientific and social-scientific literature as an example of post-disaster citizen sensing and open environmental data production.<ref>{{cite journal |last1=Brown |first1=Azby |last2=Franken |first2=Pieter |last3=Bonner |first3=Sean |last4=Dolezal |first4=Nick |last5=Moross |first5=Joe |title=Safecast: successful citizen-science for radiation measurement and communication after Fukushima |journal=Journal of Radiological Protection |date=2016 |volume=36 |issue=2 |pages=S82–S101 |doi=10.1088/0952-4746/36/2/S82 |pmid=27270965 |bibcode=2016JRP....36S..82B |doi-access=free}}</ref><ref>{{cite journal |last=Abe |first=Yasuhito |title=Safecast or the Production of Collective Intelligence on Radiation Risks after 3.11 |journal=The Asia-Pacific Journal: Japan Focus |date=2014 |volume=12 |issue=7 |url=https://apjjf.org/2014/12/7/yasuhito-abe/4077/article |access-date=8 April 2026}}</ref>
==History==
Safecast was initiated on 12 March 2011, one day after the 2011 Tōhoku earthquake and tsunami and the beginning of the Fukushima nuclear accident.<ref>{{cite journal |last1=Brown |first1=Azby |last2=Franken |first2=Pieter |last3=Bonner |first3=Sean |last4=Dolezal |first4=Nick |last5=Moross |first5=Joe |title=Safecast: successful citizen-science for radiation measurement and communication after Fukushima |journal=Journal of Radiological Protection |date=2016 |volume=36 |issue=2 |pages=S82–S101 |doi=10.1088/0952-4746/36/2/S82 |pmid=27270965 |bibcode=2016JRP....36S..82B |doi-access=free}}</ref> It was founded by Sean Bonner, Joi Ito, and Pieter Franken in response to the lack of accessible, granular, and trusted public radiation information after the disaster.<ref>{{cite web |title=History of Safecast |url=https://safecast.org/history-of-safecast/ |website=Safecast |access-date=8 April 2026}}</ref><ref>{{cite journal |last1=Brown |first1=Azby |last2=Franken |first2=Pieter |last3=Bonner |first3=Sean |last4=Dolezal |first4=Nick |last5=Moross |first5=Joe |title=Safecast: successful citizen-science for radiation measurement and communication after Fukushima |journal=Journal of Radiological Protection |date=2016 |volume=36 |issue=2 |pages=S82–S101 |doi=10.1088/0952-4746/36/2/S82 |pmid=27270965 |bibcode=2016JRP....36S..82B |doi-access=free}}</ref>
Initially centered on post-Fukushima radiation monitoring in Japan, the project developed a volunteer-based model for gathering, uploading, and openly sharing geolocated environmental measurements.<ref>{{cite journal |last1=Brown |first1=Azby |last2=Franken |first2=Pieter |last3=Bonner |first3=Sean |last4=Dolezal |first4=Nick |last5=Moross |first5=Joe |title=Safecast: successful citizen-science for radiation measurement and communication after Fukushima |journal=Journal of Radiological Protection |date=2016 |volume=36 |issue=2 |pages=S82–S101 |doi=10.1088/0952-4746/36/2/S82 |pmid=27270965 |bibcode=2016JRP....36S..82B |doi-access=free}}</ref> Over time it expanded into broader environmental sensing, including air-quality monitoring.<ref>{{cite web |title=Safecast |url=https://safecast.org/ |website=Safecast |access-date=8 April 2026}}</ref><ref>{{cite web |title=Air Quality Beta Kit |url=https://safecast.org/air-quality-beta-kit/ |website=Safecast |date=31 August 2016 |access-date=8 April 2026}}</ref>
==Data and methodology==
Safecast's principal activity has been the collection and publication of ionizing radiation measurements, especially ambient dose-rate data gathered by volunteers using mobile and fixed sensors.<ref>{{cite journal |last1=Brown |first1=Azby |last2=Franken |first2=Pieter |last3=Bonner |first3=Sean |last4=Dolezal |first4=Nick |last5=Moross |first5=Joe |title=Safecast: successful citizen-science for radiation measurement and communication after Fukushima |journal=Journal of Radiological Protection |date=2016 |volume=36 |issue=2 |pages=S82–S101 |doi=10.1088/0952-4746/36/2/S82 |pmid=27270965 |bibcode=2016JRP....36S..82B |doi-access=free}}</ref> Measurements are uploaded to the organization's database and displayed through its public map.<ref>{{cite web |title=Data |url=https://safecast.org/data/ |website=Safecast |access-date=8 April 2026}}</ref><ref>{{cite web |title=Safecast Map |url=https://map.safecast.org/ |website=Safecast |access-date=8 April 2026}}</ref>
The organization states that all collected data are released under a CC0 public-domain designation.<ref>{{cite web |title=Data |url=https://safecast.org/data/ |website=Safecast |access-date=8 April 2026}}</ref> Safecast data are also distributed through external open-data repositories, including the AWS Registry of Open Data.<ref>{{cite web |title=Safecast |url=https://registry.opendata.aws/safecast/ |website=AWS Registry of Open Data |access-date=8 April 2026}}</ref>
A 2020 study in the ''Journal of Environmental Radioactivity'' reported that Safecast had accumulated more than 120 million observations by January 2020 and used those data to estimate mean ambient dose rates in 330 cities worldwide.<ref>{{cite journal |last1=Bossew |first1=Peter |last2=Kuča |first2=Petr |last3=Helebrant |first3=Jan |title=Mean ambient dose rate in various cities, inferred from Safecast data |journal=Journal of Environmental Radioactivity |date=2020 |volume=225 |article-number=106363 |doi=10.1016/j.jenvrad.2020.106363 |pmid=33120027 |bibcode=2020JEnvR.22506363B |s2cid=226206056}}</ref> Safecast's website later described its radiation archive as the largest open dataset of background radiation measurements collected to date.<ref>{{cite web |title=Safecast |url=https://safecast.org/ |website=Safecast |access-date=8 April 2026}}</ref>
Independent validation work has also compared Safecast data with official aerial survey data gathered by the United States Department of Energy and the National Nuclear Security Administration in Fukushima Prefecture, finding the datasets to be highly correlated.<ref>{{cite journal |last1=Coletti |first1=Mark |last2=Cervone |first2=Guido |last3=Byrne |first3=John |last4=Hultquist |first4=Carolyn |title=Validating Safecast data by comparisons to a U.S. Department of Energy Fukushima Prefecture aerial survey |journal=Journal of Environmental Radioactivity |date=2017 |volume=171 |pages=9–20 |doi=10.1016/j.jenvrad.2017.01.016 |pmid=28167372 }}</ref>
==Devices==
Safecast has developed and supported several open-hardware environmental sensing devices. Its best-known instrument is the ''bGeigie Nano'', a GPS-enabled mobile radiation sensor used primarily for car-borne mapping, but also for static readings and contamination surveys.<ref>{{cite web |title=bGeigie Nano |url=https://safecast.org/devices/bgeigie-nano/ |website=Safecast |access-date=8 April 2026}}</ref> The device has been described in the scientific literature as one of the main tools used in the Safecast monitoring project.<ref>{{cite journal |last=Walsh |first=Joshua |title=Assessment of Safecast bGeigie Nano Monitor |journal=Radiation Environment and Medicine |date=2019 |volume=8 |issue=1 |pages=1–8 |url=https://remcp.hirosaki-u.ac.jp/wp-content/uploads/2019/03/rem_vol8no1_01_JoshuaWalsh-1.pdf |access-date=8 April 2026}}</ref><ref>{{cite journal |last1=Kuča |first1=Petr |last2=Helebrant |first2=Jan |last3=Bossew |first3=Peter |title=Response of the bGeigie Nano and CzechRad monitors to cosmic radiation and implications for environmental monitoring |journal=Sensors |date=2024 |volume=24 |issue=24 |pages=7915 |doi=10.3390/s24247915 |doi-access=free }}</ref>
<gallery widths="200" heights="150"> File:Safecast bGeigie Nano - closed.jpg|bGeigie Nano with closed case File:Safecast bGeigie Nano opened.jpg|Safecast bGeigie Nano opened </gallery>
250px|right|thumb|Screenshot of Safecast Tile Map website with data visualization
In 2021 Safecast introduced the ''bGeigie Zen'', an updated mobile radiation sensor based on the earlier bGeigie design.<ref>{{cite web |title=SAFECAST-10 EVENT: "Read the Air" |url=https://safecast.org/safecast-10-event-read-the-air-thu-april-22-1800-jst/ |website=Safecast |date=15 April 2021 |access-date=8 April 2026}}</ref>
Safecast has also developed air-quality sensing projects and devices to monitor particulate matter, including PM1.0, PM2.5 and PM10.<ref>{{cite web |title=Air Quality Beta Kit |url=https://safecast.org/air-quality-beta-kit/ |website=Safecast |date=31 August 2016 |access-date=8 April 2026}}</ref><ref>{{cite web |title=Safecast |url=https://safecast.org/ |website=Safecast |access-date=8 April 2026}}</ref>
==Ukraine initiative==
Following the Russian invasion of Ukraine in 2022 and Russian military activity in the Chernobyl Exclusion Zone, Safecast launched the ''bGeigies for Ukraine'' initiative in cooperation with SaveDnipro, the Czech National Radiation Protection Institute (SÚRO), and the Chornobyl Radiation and Ecological Biosphere Reserve.<ref>{{cite web |title=Announcing "bGeigies for Ukraine" |url=https://safecast.org/announcing-bgeigies-for-ukraine/ |website=Safecast |date=27 July 2022 |access-date=8 April 2026}}</ref>
According to Safecast, the project was intended to support rapid, open radiation monitoring after the withdrawal of Russian troops from contaminated areas.<ref>{{cite web |title=Announcing "bGeigies for Ukraine" |url=https://safecast.org/announcing-bgeigies-for-ukraine/ |website=Safecast |date=27 July 2022 |access-date=8 April 2026}}</ref> In September 2022, the organization stated that the initiative had gathered more than 300,000 radiation data points in Ukraine.<ref>{{cite web |title=Over 300,000 data points gathered by #bgeigies4ukraine |url=https://safecast.org/over-300000-data-points-gathered-by-bgeigies4ukraine/ |website=Safecast |date=17 September 2022 |access-date=8 April 2026}}</ref>
==See also== * Citizen science * Fukushima Daiichi nuclear disaster * Environmental monitoring * Open data
==References== {{Reflist}}
==External links== {{Commons category|Safecast.org}} * {{Official website|https://safecast.org/}} * [https://map.safecast.org/ Safecast Map]
Category:Citizen science Category:Crowdsourcing Category:Emergency organizations Category:Environmental organizations established in 2011 Category:Fukushima nuclear accident Category:Ionising radiation detectors Category:Non-profit organizations based in Japan Category:Open data Category:Radiation protection organizations Category:Shibuya