A squib is an attachment to a fuse, when pulled, initiates the fuse to burn. The only link I know that may give insight to this is www.isee.org
Many underground mines will use them for the allowable time given to vacate the mine for a shot.
The last mine I saw use them was in Silver City, NM, USA
I had to use them to set off a shot at this mine because it was the only method they would allow.