AN investigation by the Department of Labour hopes to determine how a Hawera man sustained a "substantial" head injury while working at Fonterra's Whareroa plant in Hawera. The man ? Andrew Paul Smith, 44, ? had been installing a new piece of equipment when it appeared he suffered a severe blowto the head that killed him last Friday. Detective Sergeant Blair Burnett, of Hawera police, told the Wanganui Chronicle it appeared an item of machinery had inflicted a substantial wound that caused Mr Smith's death. However, an autopsy would determine the cause of death, he said. Mr Smith was an electrician but had worked for Fonterra before and was well known to staff, Fonterra spokesman John Redwood said. "Our thoughts are with his family." "There is concern that it happened and the Department of Labour had carried out a preliminary investigation," Mr Redwood said. Control of the site was given back to the company on Saturday afternoon. Mr Redwood said he didn't know the details of what happened and would rather wait until all the information was known before commenting. Department of Labour Taranaki manager Brett Murray said because it was a workplace accident it fell into their jurisdiction. Mr Murray said an investigation into the accident had began but it could be several months before the outcome is known.