Emergency services are currently in attendance at Elite Fitness in Cowper Road on Gilwilly Industrial Estate in Penrith.
Police and fire are in attendance.
A 100m cordon is in place as a precaution due to the potential for a gas leak.
There is no report of anyone having been injured at this time.
People are asked to avoid the area and respect the cordon put in place.
People working in Gilwilly Industrial Estate are asked to stay inside unless asked to do otherwise by the emergency services.