In a statement on Cwmcarn High School's website, headteacher Jacqui Peplinski said "concerns were dealt with swiftly".
"There was no risk to any staff or learner and the relevant support services were contacted as a precautionary measure."
"Cwmcarn High is a caring and safe environment and we are committed to everyone’s safety."
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It will be wet and windy this evening and through much of tonight with some heavy rain at times.
Welsh golfing legend Ian Woosnam has set his sights on securing a home victory at the Wales Senior Open in Newport.
It will be a bright start to Saturday, with some sunny spells. However, cloud and rain will reach the far west by late-afternoon.