Europe and incidents

Documented incidents

These are 23 documented incidents at biogas and biomethane plants in Europe. Across 13,171 European stations there were more than 800 accidents in 10 years, most without serious consequences[13]: incidents are frequent, mostly minor and sometimes severe. The best-documented serious risk is water pollution[14][15].

1. 26.11.2024 Flemløse (Fyn) · Denmark

   Construction accident

   During construction of a concrete silo at a biogas plant, the internal formwork collapsed while the roof was being cast, bringing down about 750 t of concrete. A construction-safety accident, not a process accident.

   3 workers killed, several injured.[16][17][18]

   Confidence: High

2. 08.06.2024 Tarm (Jylland) · Denmark

   Structural failure

   A slurry tank of about 8,000 m³, built within the previous six months, collapsed; a second tank was found cracked and leaking.

   Slurry up to about 1 m deep on site, contained there; no injuries; extended shutdown.[19]

   Confidence: High

3. 21.07.2023 Mignéville (Meurthe-et-Moselle), Blette · France

   Water pollution

   The river Blette was polluted (turbid water, fish deaths); the slurry came from a neighbouring farm store with a broken valve. A criminal settlement was concluded with SARL Biorecycle, operator of a methanisation and cogeneration unit. The link between the plant and the spill is not fully clear.

   Significant fish deaths; criminal settlement signed on 23.10.2024.[20]

   Confidence: Medium

4. 25.02.2023 Mille / Pall / Atert · Luxembourg

   Water pollution

   Digestate from a biomethanisation plant reached three rivers. A 2018 national inspection had found 35 of 61 final digestate tanks non-compliant, including one at this plant.

   Prosecutor's investigation opened; the government ordered a review of all biomethanisation permits.[14]

   Confidence: High

5. 05.09.2022 Ariège · France

   Biogas release

   Water in a shredder motor tripped the power supply; mixing stopped, foam blocked the gas line and the pressure rose until the gasholder's outer membrane failed.

   Night-time biogas release; gasholder membrane damaged.[21]

   Confidence: High

6. 28.08.2022 Cher · France

   Structural failure

   A digester cover was torn off by excessive gas accumulation; one of two mixers stopped and material blocked the gas pipe to the safety valve.

   Digester cover destroyed; biogas release.[21]

   Confidence: High

7. 18.06.2022 Gironde · France

   Biogas release

   A flare failure caused the safety valves to open on a Saturday; the controller was replaced the next day and grid injection restored two days later.

   3,500 Nm³ of raw biogas emitted to the atmosphere.[21]

   Confidence: High

8. 20.05.2022 River Ottery, Warbstow (Cornwall) · United Kingdom

   Water pollution

   About 2,300 gallons of digestate escaped when a hose broke during transfer to a tanker; the farmer washed the spill into a watercourse and did not report it.

   471 dead fish counted, about 1,610 estimated (Atlantic salmon, brown trout); populations had not recovered two years later. Fine of £215 plus £3,550 costs.[22]

   Confidence: High

9. 20.01.2022 (sentença) Saint-Bonnet-de-Salers / Sainte-Eulalie (Cantal) · France

   Water pollution

   Repeated leaks of livestock effluent (several hundred m³ according to the FNE association) from two methanisation sites since 2017, due to defective storage areas and undersized retention basins. One site was suspended in 2020.

   Streams polluted and livestock watering points unusable. The Aurillac court imposed a €200,000 fine and suspended prison sentences on the managers.[23]

   Confidence: Medium

10. 16.03.2021 Seine-et-Marne · France

    Biogas release

    Foaming in a digester (inputs had changed a week before) blocked the relief valve; the overpressure tore off the flexible roof. The operator did not hear the first night-time alarm.

    Biogas released to the atmosphere; digester roof destroyed.[21]

    Confidence: High

11. 03.12.2020 Avonmouth, Bristol · United Kingdom

    Explosion

    A silo of treated sewage biosolids exploded while people were working on its roof. This is not a biomethane plant but a wastewater site; it only illustrates the gas hazard in organic-material silos.

    4 killed, 1 injured. In July 2026 the Health and Safety Executive authorised criminal charges against Wessex Water.[24][25]

    Confidence: High

12. 17.08.2020 Châteaulin (Finistère), Aulne · France

    Water pollution

    A tank overflowed after a technical incident and about 400 m³ of digestate reached the river Aulne upstream of a drinking-water plant, raising ammonium levels.

    Tap-water use restricted in about 50 communes, for about 180,000 people, for about 5 days. Engie Bioz was fined €150,000 (€50,000 suspended) on 16.11.2023.[26][27]

    Confidence: High

13. 30.07.2019 River Mole, South Molton (Devon) · United Kingdom

    Water pollution

    Anaerobic digestate leaked from a pipe during land spreading and washed into a tributary after heavy rain.

    An estimated 15,600 fish killed along 4.7 km. The company was fined £2,000 plus costs.[28]

    Confidence: High

14. 09.06.2019 Loir-et-Cher · France

    Pipeline rupture

    An underground biogas pipe (6 bar) between storage and a grid injection station ruptured from overpressure; a pressure-regulator failure is suspected.

    Biogas leak; a crater about 1 m wide in the ground.[21]

    Confidence: High

15. 11.03.2019 Seedorf (Fribourg), Sonnaz · Switzerland

    Water pollution

    About 50 m³ of digestate from a methanisation plant flowed into the river Sonnaz.

    518 dead fish.[29][30]

    Confidence: High

16. 04.04.2018 Yonne · France

    Explosion

    Explosion followed by fire at a post-digester gasholder during the test of an agitator after maintenance; the agitator support was not earthed, causing an electric arc in an ATEX zone. Certified inspections had not detected it.

    Explosion and fire; equipment damage.[31]

    Confidence: High

17. 15.09.2017 Loiret · France

    Structural failure

    A digester membrane burst, throwing off pieces of concrete wall; a flexible liquid-digestate tank was pierced and emptied. Cause: foaming from organic overload; the high-level alarm failed to trigger.

    Digestate spilled on site; equipment destroyed.[31]

    Confidence: High

18. 16.06.2017 Yvelines · France

    Biogas release

    Methane sensors overheated in direct sun and triggered emergency stops; pressure rose, the safety valves opened and the control system also shut off the flare.

    Raw (unburned) biogas released to the atmosphere over 3 days.[31]

    Confidence: High

19. 20.01.2017 Finistère · France

    Odour

    A process imbalance in a methaniser treating dairy effluent (effluent bypass, frozen pH-correction line) overwhelmed the air treatment.

    Nauseating odours affected residents for 4 days.[31]

    Confidence: High

20. 12.03.1997 Peschiera del Garda · Italy

    Explosion

    Explosion during repair work inside a concrete biogas fermentation silo; the silo roof was blown off. Gas residue and welding work were identified as the cause.

    2 workers killed, 1 seriously injured.[32]

    Confidence: High

21. 11.2005 Rhadereistedt (Niedersachsen) · Germany

    Toxic gas (H2S)

    Hydrogen sulphide was released in a closed reception hall when protein-rich slaughterhouse waste was tipped into a receiving tank at a biogas plant.

    4 dead (3 workers and a truck driver), 1 seriously injured, about 10 firefighters intoxicated.[33][34]

    Confidence: High

22. 02.2021 Caparroso (Navarra), Aragón · Spain

    Water pollution

    Digestate from a biomethanisation process at a cattle macro-farm was sprayed by irrigation pivots without authorisation; the runoff reached the river Aragón, inside a special area of conservation.

    Two Valle de Odieta board members sentenced to 1 year in prison and 14 months' disqualification (reported 27.10.2025).[35]

    Confidence: High

23. 07.2024 Favières (Seine-et-Marne) · France

    Water pollution

    One of two flexible bags storing liquid digestate failed; the contents reached the river crossing the site.

    Heavy fish deaths downstream; emergency prefectoral order of 15.07.2024.[36]

    Confidence: Medium

Open the map Leaks, fires and explosions: what research says