no there is no flash. It just lights. It is very safe to use in a outhouse blind. I use it in mine all the time. It isnt like using deisel. There is no smell and no soot. It is kinda like using a sterno can. The alcohol will ignite but there isnt a flash of any kind. It is safe enough that I let my teenagers use them. Try making one and lighting it at home just to see what it will do. This little backwoods heater thingie has kept me from freezing my buns off plenty of times.

Thanks Penny!

Kindest Regards,

-Will in Maryland

Will, shouldn't that be "warmest regards"?

Ha!

Warmest Regards (to all users of this wonderful device)

-Will in Maryland