Chemicals caused an explosion and subsequent fire on Tuesday morning at the former headquarters of electrolyser maker McPhy, in the village of La Motte-Fanjas, southeast France, which had been vacated at the end of January.

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“An explosion that occurred during the transfer of chemical materials caused a liquid spill outside the McPhy Energy premises in La Motte-Fanjas followed by the start of a fire,” said a press release by the local government in Drôme prefecture.

Local newspapers said a 200-litre drum outside the building had exploded and then caught fire at 10am during a clean-up of the site.

None of the five McPhy employees at the site were injured.

“The fire was brought under control by firefighters who were quickly on the scene,” said the local authority, adding that the building suffered no damage.

There has been no word on what caused the fire, but Hydrogen Insight has learned that magnesium hydride was manufactured at the site — a material that can explode on contact with water, and even ignite when exposed to air.

McPhy moved to its new headquarters in Grenoble in October 2022.

A few weeks later, in early November, the company took a final investment decision on building a new 1GW electrolyser factory in northeast France after being awarded up to €114m ($121.6m) of state aid from the French government. It is due to be commissioned in the first half of 2024.