Paris, Aug 4 : An explosion in a factory in the city of Bergerac in southwest France left eight people injured, one in critical condition, a French daily has reported. As many as 35 people were overcome with fumes from the explosion, which happened on Wednesday afternoon, local authorities were quoted as saying by Le Figaro newspaper, Xinhua news agency reported. French Interior Minister Gerald Darmanin wrote on his social media that those injured in the explosion were being treated. The factory owned by the Eurenco company is specialised in the fabrication of explosives. However, the origin of the explosion remains unknown. A total of 60 firefighters and 20 police officers attended the scene of the explosion. Two helicopters from intensive care units at Bergerac hospital were also present, with the hospital on high alert. The Manuco factory, present in Bergerac since 2013, is listed as a "high threshold Seveso" establishment, with an activity linked to handling, manufacturing, using or storing dangerous substances. In France, 705 industrial sites are on high threshold Seveso, while 607 are on low threshold. In 2019, a fire broke out at the Lubrizol factory, which was on high threshold Seveso, in the city of Rouen. Several people were injured, including eight requiring hospitalisation. /IANS