I work with a guy who was involved in a near miss incident with these cannisters. They are not risk free, although you could argue that the accidents are rare and potentially worth the risk?

https://www.busnews.com.au/industry-news/1201/gas-bus-explos...

https://www.ctif.org/news/cause-stockholm-cng-bus-explosion-...

https://hal-ineris.archives-ouvertes.fr/ineris-00976180/docu...