An incident Sunday at a biogas plant in France taught local firefighters that under the right conditions even manure can become an explosion risk.

Firefighters with Departmental Service of Fire and Rescue 29 in Chateaulin responded to a plant where fuel is extracted from manure by biological decomposition. A large metal building used to store fermenting manure had begun releasing smoke, the newspaper Le Telegramme reports.

Rapidly reproducing bacteria in standing piles of manure cause release of methane that appears to be smoke. While the risk of ignition is low, that much methane building up in a confined space can become an explosion hazard.

Methodically the firefighters removed nearly 450 cubic meters of manure from the warehouse, spread it across the ground and used fire hoses to moisten it. Runoff was channeled into a retention pond to avoid environmental impact.

Despite its environmentally friendly intentions, the biogas plant is earning a reputation for being bio hazardous. Last week more than 400 cubic meters of digestate overflowed from a tank at the plant, potentially contaminating tap water used by 180,000 area inhabitants.

Those inhabitants went five days limited to two bottle of water per day per person.