Fagnes fire: machine had prior incident, probe hears

Belgian prosecutors have confirmed that the agricultural machine suspected of igniting the devastating August wildfire in the Hautes Fagnes nature reserve had already caused an incident the day before the blaze — a finding that sharpens scrutiny of how the brush-cutting work was managed in drought conditions.

The Liège prosecutor’s office, quoted by RTBF, said a problem involving the machine had been noted on 13 August, the day before the fire broke out. “We can confirm that a problem involving the machine had already been noted the day before,” spokesperson Rosalie Heinen said. “This element is taken into account in the ongoing investigation.”

The fire and its scale

The blaze began on Friday 14 August near the Hautes Fagnes plateau in Wallonia’s Liège province. Parachutists preparing to jump nearby spotted flames from their aircraft and filmed the smoke column. Ultimately, more than 3,366 hectares burned — roughly the area of the city of Verviers, and the majority within a protected Natura 2000 zone, making it the most serious fire in Belgian history.

The origin hypothesis centres on a hammer flail mower, or gyrobroyeur à marteaux, used for authorised brush-cutting (fauchage) on the parcel. Such machines rotate at around 2,000 revolutions per minute and can throw sparks when their blades strike stones, wood or earth — a recognised fire risk in tinder-dry conditions.

A machine reused without repair

According to RTBF, on 13 August a private company mandated by the Département de la Nature et des Forêts (DNF) carried out brush-cutting all day. That day, the machine caused an incident. One source close to the company said the machine produced a smoke emission controlled by DNF agents on site; another DNF source said part of the mower overheated and agents emptied their water reserves onto it to cool it and secure the equipment.

Crucially, RTBF reported that the next day the flail mower was put back to work from early morning “without any maintenance or repair.” The machine had left the cutting zone before mid-morning — it was no longer on site when the fire broke out around midday.

The private company declined to comment but said there was no fire when its worker left the site. RTBF noted that a fire can smoulder for hours before flames appear.

Expert warnings on drought risk

Agricultural contractor Bruno Wibrin, who regularly uses flail mowers, told RTBF the equipment is dangerous in dry conditions. “With inertia, as the rotor turns at 2,000 rpm, the hammers go vertical,” he said. “It can be dangerous — I would not have used it in August.”

The RTBF Décrypte and Investigation teams went further in a detailed reconstruction of the fire’s start, using parachutists’ footage and Copernicus Sentinel-2 satellite imagery to pinpoint the ignition zone about 300 metres west of the Croix Mockel, along a path called the allée du grand fossé. Jean-Luc Evrard, director-general of a company that sells and repairs such machines, was blunt: “It’s scandalous to have mandated a contractor with such a machine in well-known drought conditions. The activity with mechanised machines on such dry sites was not at all recommended.”

A patchwork of warnings and bans

Questions are also being raised about prevention. On 10 August, the Celex expertise cell warned that “currently and until 15 August, the fire risk for open environments is high.” For Luxembourg province, a circular banned brush-cutting until 14 August. But the Hautes Fagnes lie in Liège province, where no explicit brush-cutting ban was imposed.

Liège governor Hervé Jamar said he took all measures within his power, citing a police order published on 2 July and valid until 6 September. “We have taken a clear and unambiguous order on fire risk for the whole of Liège province,” he said. “I don’t see what I could have done more… I am not going to forbid a combine harvester from operating.”

The Service public de Wallonie declined to comment, citing the secrecy of the investigation. Its spokesperson, Nicolas Yernaux, said he was “very surprised that the Prosecutor himself confirmed the information.” “We are talking about the most serious fire in Belgium’s history,” he added.

Judicial inquiry under way

The Liège prosecutor opened a judicial inquiry for involuntary fire (incendie involontaire). Two experts — one specialising in fire, one in driving and mechanics — have been appointed, and several months will be needed before their final reports. Experts have delineated a restricted ignition zone of about 500 square metres.

David Roussel, a French forest technician deployed through the EU Civil Protection Mechanism, said meteorological indices that day pointed to a high risk of accidental ignition. “On 14 August, we had a number of indicators showing the situation was favourable to accidental fire outbreaks,” he said.

The brush-cutting itself is a long-standing DNF technique to restore biodiversity on the plateau by controlling Molinia grass. For the past two years, the work has been subcontracted to private companies. The communes of Baelen and Waimes have filed civil-party actions as the question of legal responsibility — the contractor, the DNF, or the Walloon Region — remains open.

What’s next

As investigators work toward final expert reports, the case is exposing a governance gap between provincial warning systems and on-the-ground practice. The revelations of a prior incident add weight to the central question: whether a known risk was allowed to proceed. With a million-euro restoration pledge from the water group Spadel and continued surveillance of the burn zone, the Hautes Fagnes will take years to recover — and the inquiry’s findings will shape how Belgium manages fire risk in its most protected landscapes.