Enesco Limited, of Carlisle, pled guilty over the incident, which happened at its workshop at Borders Fine Arts, Langholm.
No one was injured in the explosion, which happened on July 11, 2012, but there was considerable damage to the property. An investigation failed to uncover the source of the blast.
The company admitted at Dumfries Sheriff court that it breached rules contained in the Dangerous Substances and Explosive Atmospheres Regulations Act.
Gary Aitken, head of the Crown Office and Procurator Fiscal Service Health & Safety Division said: "It was simply good fortune no employees were in the vicinity of the explosion and that no one was injured or killed."