Public dossier The risks Over 800 accidents in 10 years
Leaks, fires and explosions
Across 13,171 European biogas stations there were more than 800 accidents in 10 years, most without serious consequences. Modelled effects usually stay within tens of metres.
What is known
Across 13,171 European biogas stations there were more than 800 accidents in 10 years; most had no serious consequences and 3 were serious for human life. In France, methanisation events in the ARIA accident database rose 82% in 2017 compared with the previous five-year average, and the responsible public body says the sector "has not yet reached maturity". The hazards are fire, explosion, digester rupture, gas leaks and spills.
A fatal toxic-gas precedent occurred at Rhadereistedt (Germany, 2005): a hydrogen sulphide release in a closed hall killed 4 people, three workers and a driver. The acute toxic risk is mainly to the people who work there.
How far
In the generic scenarios of the French institute INERIS, the effects of a leak, fire or explosion at well-designed plants stay within tens of metres, up to about 100 m. At Sousel the calculated hazard zones were 27 m and 37 m; at German plants, 25 to 60 m. The theoretical worst cases, very unlikely, reach 230–420 m for glass breakage.
In Guarda
The site has a "High" and "Very High" fire hazard rating. Satellite imagery shows a burnt area next to the parcel; the date and cause of the fire are still to be confirmed. Whether the plant would fall under the major-accident (Seveso) regime is unknown, because its capacity has not been disclosed.
What to ask the promoter
- What risk analysis has been done, and with what effect distances?
- What fire-protection strips will the site have?
- Who responds to an alarm at night?
- Air and odours
- Water
- Soil
- Traffic and noise
- Leaks, fires and explosions
- House values
- Health: what the evidence says
Sources on this page
- Kotek, Trávníček e Blecha (2015), Chemical Engineering Transactions 43: 1933–1938: acidentes em estações de biogás europeias
- Scénarios accidentels et modélisation des distances d'effets associées pour des installations de méthanisation de taille agricole et industrielle (rapport Ineris-201652-2437679-v2.0)
- Flash ARIA: Méthanisation, comment développer la filière sans développer les risques ?
- Informationspapier zur Sicherheit bei Biogasanlagen
- Parecer da Comissão de Avaliação, procedimento de AIA n.º 3857: Unidade de Biometano de Sousel
- Auswirkungsanalyse nach KAS-18: Biogasanlage Neu Sterley (Entwurf)
- Gutachten zum angemessenen Sicherheitsabstand (Achtungsabstand): Biogasanlage Sielenbach, Bericht 10011/BE02V01
- Ata da reunião ordinária da Câmara Municipal da Guarda de 19 de junho de 2026 (Ponto 18, Proposta VPCM n.º 10/2026)
- MOV.AP: medições sobre imagem de satélite, outubro de 2026 (distâncias do limite da parcela à zona de exploração de água, quintas e aldeias)
Kotek, Trávníček e Blecha (2015), Chemical Engineering Transactions 43: 1933–1938: acidentes em estações de biogás europeias
Scénarios accidentels et modélisation des distances d'effets associées pour des installations de méthanisation de taille agricole et industrielle (rapport Ineris-201652-2437679-v2.0)
Flash ARIA: Méthanisation, comment développer la filière sans développer les risques ?
Informationspapier zur Sicherheit bei Biogasanlagen
Parecer da Comissão de Avaliação, procedimento de AIA n.º 3857: Unidade de Biometano de Sousel
Auswirkungsanalyse nach KAS-18: Biogasanlage Neu Sterley (Entwurf)
Gutachten zum angemessenen Sicherheitsabstand (Achtungsabstand): Biogasanlage Sielenbach, Bericht 10011/BE02V01
Ata da reunião ordinária da Câmara Municipal da Guarda de 19 de junho de 2026 (Ponto 18, Proposta VPCM n.º 10/2026)
MOV.AP: medições sobre imagem de satélite, outubro de 2026 (distâncias do limite da parcela à zona de exploração de água, quintas e aldeias)
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