A man was killed when a charging e-cigarette exploded and ignited oxygen equipment he is believed to have been using, fire service in the English town of Wallasey said on Friday.
The 62-year-old victim was found in the living room of a house in Penkett Road, Wallasey.
A small fire in the bedroom of the property had gone out before firefighters arrived, Merseyside Fire and Rescue Service (MFRS) said.
The exact cause of death is yet to be established, the BBC reported.
An MFRS spokesman said: "The subsequent fire investigation identified that an e-cigarette that had been charging in the bedroom exploded, caught fire and ignited the oxygen tube of an oxygen concentrator, which may have been in use by the occupier."
Myles Platt, MFRS area manager, said: "The investigation into the cause of this fire is continuing but at this stage it is thought that the charging device being used at the time may not have been the one supplied with the e-cigarette."
"We urge people to always use electrical equipment in accordance with the manufacturer's instructions and guidance, always ensure that no electrical items are left charging overnight or left unattended for a long period when being charged, and do not mix parts from different e-cigarettes."
Since January, nine fires involving e-cigarettes have been recorded on Merseyside.
An electronic cigarette is a battery-powered vaporiser which simulates tobacco smoking by producing an aerosol that resembles smoke.