Yes they can be for sure - I only use mine when I get up in the
morning to warm things up a bit - if I need to keep it on all day -
probably too cold to be camping anyway
Ken J
>ANY un vented gas heater if it malfunctions can KILL you. I have received a
>lot of static from owners of these catalytic heaters because of my stand
>against them but maybe They have never had to help remove a family
>from a home
>after they ceased to exist because of a suppository safe heater.
>Just my 2 cents.
>Jim Smith