Toxic mercury leak contained in Ham East

A faulty blood pressure tester had hearts racing at Southern Cross Hospital this afternoon after it busted and started to leak toxic mercury.

Four fire appliances, including the mobile hazardous materials unit, rolled in to deal with the liquid metal problem in Hamilton East at 1.45pm.

Hamilton senior station officer Dave Gunn said it was an aged blood pressure testing unit that closed into a plastic case.

''When they closed it, they heard something crack and opened it to find the tube had broken or cracked and it was letting the mercury out,'' Mr Gunn said.

Mercury, a heavy metal, is liquid at room temperature and poisonous to humans.

Common symptoms include itching, burning or pain, skin discoloration such as pink cheeks, fingertips and toes, swelling, and shedding of skin.

Mr Gunn said hospital staff closed the tester immediately and put it in a black rubbish bag.

''The hospital staff were excellent.''

He said the fire service contained the mercury and it will now be taken to a chemical dump in Auckland.