Staffordshire Fire and Rescue Service went to an incident at Queen’s Hospital and Hobbycraft, Burton-on-Trent yesterday.
Two fire engines from Longton and one from Burton attended, after four Hobbycraft employees went to the hospital's A&E department after coming into contact with the substance.
The powder was later identified as Napthalene, which is a low risk product, and used to fumigate products shipped from abroad.
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Some showers at first this evening, gradually clearing overnight. Tomorrow, a mostly dry day but with a few showers.
A good deal of cloud this evening and overnight, with showery outbreaks. Tomorrow, generally cloudy, with some sunny intervals.