Abstract: A plant for producing silicon thin-film solar cells has at least one chamber (1) in which the silicon thin-film is deposited from silicon hydride gas during the production process. The chamber (1) is subsequently cleaned of contaminants by an etching process e.g. with sulfur hexafluoride as the etchant gas. The waste gas formed during the production process and containing silicon hydride is supplied to a burner (6) and subsequently filtered. The waste gas formed during the etching process and containing sulfur hexafluoride is washed with water after having been supplied to a burner. The hydrofluoric acid formed by burning of the sulfur hexafluoride is separated from the washing water.