The ACTU has reissued its warning to the government to ban engineered stone. The nation's peak trade union body says the popular material used for kitchen bench tops needs to be banned because the high levels of silica it contains cause the incurable lung disease, silicosis. Reports have shown as many as 1 in 4 stonemasons who work with engineered stone develop the deadly disease and more than 600,000 people in Australia are exposed to it at work.