The family of a Rotherham man who died on his 43rd birthday have no idea how he caught an asbestos-related disease at such a young age.
Lawyers acting for Ian Edmondson before his death last month have been unable to establish whether or not he came into contact with the deadly dust.
Mr Edmondson, of Barron Road, Brampton Bierlow, became ill with shortness of breath around Christmas 2011.
A biopsy at Doncaster Royal Infirmary in March 2012 confirmed he had mesothelioma, usually associated with asbestos exposure.
Mr Edmondson, a glassworker, died at home on Sunday, October 27, his 43rd birthday. His wife, Jillian, said she was not aware of any asbestos exposure in his working life at the glassworks or in his previous occupation as a signfitter.
Lawyers had been unable to identify where there had been any contact or exposure and Mrs Edmondson had no idea where else he might have been exposed to it.
Fred Curtis, Rotherham deputy coroner, recorded a narrative conclusion that it was more likely than not there was exposure to asbestos at an unknown place outside or inside an industrial environment.