Dynamite is a highly explosive mixture formed by absorbing nitroglycerin into a diatomaceous earth substrate, such as clay.
The Black Rock
A cache of extremely old highly-unstable dynamite was discovered in the hold of the Black Rock and very likely was intended for use in mining operations. It appears the stash was first discovered by Danielle Rousseau during her long exile on the Island. The dynamite from this cache has been used on a number of different occasions:
Danielle Rousseau used dynamite from the Black Rock to set at least one trap for the Others.
- Danielle Rousseau rigged her shelter with dynamite. When Jack and Sayid approached, they inadvertently triggered a tripwire which caused the entire shelter to detonate. ("Numbers")
Blowing open the Hatch
Danielle revealed the location of the cache to the survivors, taking Jack, Locke, Hurley, Kate and Leslie Arzt to the old wreck. The survivors carefully extracted six sticks of dynamite to carry in two separate backpacks with the intent to use it to blow open the Hatch.
- Arzt accidentally blew himself up while demonstrating how to safely handle dynamite. ("Exodus, Part 2")
- Kate used one of the sticks of dynamite to distract or repel the Monster which was trying to drag Locke into a mysterious hole in the ground.("Exodus, Part 2")
- Three of the sticks were used to blow open the Hatch. ("Exodus, Part 2")
- Later, Hurley was planning use the remaining dynamite to destroy the food reserves that were found in the Swan, but was talked out of the act by Rose. ("Everybody Hates Hugo")
- Eko ultimately uses the leftover dynamite in an unsuccessful attempt to breach the blast doors into the Swan's computer room. ("Live Together, Die Alone, Part 1")
Battle at the beach camp
- Much later, Locke observes Rousseau removing another box of dynamite from the Black Rock. ("The Brig")
- Jack and Rousseau detonate a random tree in the jungle as a proof of concept for his plan. ("Greatest Hits")
- Bernard and Sayid killed five of the Others by shooting guns at dynamite—a trap they set for the Others at the beach camp. Jin attempted to set off a third dynamite trap, but missed his shot. ("Through the Looking Glass, Part 1")
At Claire's hut
- Inside Claire's hut, when Claire is holding Jin and Justin captive, dynamite can be seen as part of her supplies. ("Lighthouse")
- Richard attempted to commit suicide by lighting a stick of dynamite within the Black Rock. Jack stayed at Richard's side, to prove that Jacob brought them both to the island for a reason, and the fuse burned out before it could explode.
- Ilana took some of the dynamite with the intent of using it to blow up the Ajira Flight 316 plane. She dropped it heavily and it detonated, killing her instantly. ("Everybody Loves Hugo")
The last of the dynamite
- After Ilana's death, Jacob's followers traveled back to the Black Rock to retrieve more dynamite. Hurley, following guidance from the spirit of Michael, manages to sneak onboard the ship and ignites the remaining dynamite, narrowly escaping before the explosion of the Black Rock. ("Everybody Loves Hugo")
The DHARMA Initiative
It appears the DHARMA Initiative had their own store of dynamite which was most likely used in ground-clearing for various stations and other facilities on the Island. In 1977 Horace Goodspeed, while intoxicated, was using lit dynamite to destroy trees near the sonar fence. Phil, who was on guard duty at the security office, immediately identified the dynamite upon seeing Horace on the monitor. Later Horace does not recognize the name Black Rock, indicating the dynamite he used came from a different source. ("LaFleur") This further evidenced by Richard resolving to go back to the Barracks where he hoped grenades and dynamite might still be. ("Everybody Loves Hugo")
- The dynamite transport scene (and Montand's name) are an homage to the movie The Wages of Fear, according to Damon Lindelof in the 5/19/06 podcast. The plot of the extraordinarily tense movie involved transport of dangerous explosives in a desperate situation with few safety precautions. It also featured the idea of separating into two groups that keep their distance from one another, planning for the "worst-case-scenario" of one of them not making it, that the other will reach the destination with adequate explosives to accomplish the mission (much like Jack's idea).
- Dynamite has played a central role in the season finales of seasons 1-3.