Emergency crews were called to clean up mercury that was spilled at Smiths Hill High School this afternoon.
The NSW Fire Brigade's hazardous materials crews from Wollongong and Shellharbour attended but were forced to conduct a quiet mop up as Higher School Certificate exams were underway nearby.
The mercury was spilled accidentally and covered an area approximately 2sqm about 2.10pm.
Crews were in their splash suits and breathing apparatus to prevent contact with the toxic metal during the clean-up operation.