The Standard P&I Club have raised a safety alert on e-cigarettes:
http://www.standard-club.com/news-and-knowledge/news/2018/06/web-alert-personal-injury-e-cigarette-battery-explosion.aspx
And you thought that e-cigarettes were safer than tobacco??
The US Navy banned e-cigs on ships for this reason, had a few incidents of battery explosions(generally it was sailors being dumb and fucking with stuff they shouldn’t have been.)
I am on a Navy hybrid ship now. Banned on Navy and MSC ships. Despite the ban, they are still in use.