Fire officials in the U.K. say an electronic cigarette explosion is behind the death of a 62-year-old man.

The Merseyside Fire and Rescue Service said Friday that a small fire in the man's bedroom is believed to have started when an e-cigarette that had been charging exploded, caught on fire and ignited the oxygen tube of an oxygen concentrator.

Fire officials said there have been nine fires involving e-cigarettes in Merseyside, located about 350 kilometres northwest of London, since January 2013.

The death has prompted Merseyside fire service to launch a campaign advising area-residents on the safe use of e-cigarettes.

The electronic devices heat a liquid nicotine solution, creating vapour that users inhale.

E-cigarette users say the devices satisfy their nicotine fix without the thousands of chemicals found in regular paper-and-tobacco cigarettes. However, there's little research on the health risks of e-cigarettes.

Health Canada has warned Canadians not to buy or use electronic smoking products because their safety and quality hasn't been fully studied.

Despite the safety concern, North America's e-cigarette market is ballooning, with a recent U.S. study showing it's expanding at a rate of 10 brands per month.

With files from The Associated Press