Staffordshire's first decontamination drill had to be abandoned yesterday after firefighters were called to a real emergency.
The county's Fire and Rescue Service and Staffordshire Police were due to simulate the fall-out following a chemical incident or dirty bomb in Newcastle-under-Lyme.
Before they had time to set up inflatable showers and screening areas fire crews were called to a chemical spill at a factory unit in Chesterton, Staffordshire.
More than 100 public services students were on stand-by at Newcastle-under-Lyme College where they would be "decontaminated".
The event will be rescheduled to take place in the next few weeks. Staffordshire Ambulance Service, which was not taking part, and firefighters were called to Pallet Express System, on the Lymedale Business Park, at 9.25am.
A 302-kilo drum of trichloroethylene - a chemical used in cleaning solutions - had been split as it was moved to the warehouse.
No-one was affected by the substance, which can cause respiratory problems and eye and skin irritation. Keith Griffith, watch manager at Newcastle-under-Lyme fire station, said: "The cost implications are minimal as we had called in stand-by crews and part-time officers to cover stations."
The Home Office drew up emergency plans in May 2004 to deal with a mass terror strike on British soil, accidents or natural disasters.