Workers from the Assmang Ferro-Manganese Smelter [joint venture African Rainbow Minerals, Assore] in Cato Ridge have disrupted the Labour Department's formal inquiry into the exposure of poisonous fumes at the company...The inquiry was due to start today after numerous reported cases of manganese exposure dating as far back as 2005...Meanwhile the National Union of Metalworkers (Numsa)...regional secretary, Petros Ngcobo, says...they want an explanation as to why workers were allowed to work in an area that had already been declared unsafe.