Police are warning people to stay away from a mine in the Forest of Dean.
This after offenders tried to break into a metal container at Heywood Drift Mine on Monday.
Police say breaking into the mine itself ciuld have deadly consequences, as the mine contains a mixture of unbreathable gases known as black damp.
Police Sergeant Simon Clemett, of the Forest North Safer Community Team said:
“These attempted break-ins are obviously of concern to the owners not just because of the cost and inconvenience they have caused but also because of the possible consequences for the offenders if they decide to target the mine next. The mine contains black damp, which can be fatal if you are exposed to it for more than a couple of minutes.
“While the mine is securely sealed and barricaded by half a ton of rubble, the owners are keen to get the message out there. They will also be putting more signs up to make the presence of the gas in the mine very clear.”
Anyone who has any information about the incident should call Gloucestershire Police on 0845 090 1234 , or Crimestoppers anonymously on 0800 555 111 , quoting incident 120 of July 12.