The National Glass Centre in Sunderland was forced to close its doors this afternoon.
The centre said it would also be closed to the public tomorrow.
A message on its Facebook post, said: "Due to unforeseen circumstances, National Glass Centre will be closed for the rest of today, April 21, and tomorrow Sunday, April 22.
"However, please note adults courses will still go ahead as planned, please check in at the main reception on arrival.
"We apologise for any inconvenience caused."