No, they aren't that powerful.
Fertiliser and sugar make good ones, which I use when I go ratting.
How did they ignite in his pocket???? The mix needs high temperature to ignite, from either a fuse or jet flame lighter.Jonny made home made smoke grenades.
One almost melted a team mates leg when it ignited n his pocket.
And another charred Jonnys hand with chemical burns after using it as a launch pad...
Not reccomended
Cool video though, those look safe