Any closeable item (book, box, bottle, chest, coffer, coffin, door, drawer, and so forth) can be warded by a fire trap spell. The spell is centered on a point selected by the spellcaster. The item so trapped cannot have a second closure or warding spell placed upon it.
A knock spell cannot affect a fire trap in any way - as soon as the offending party opens the item, the trap discharges. As with most magical traps, a thief has only half his normal find traps score to detect a fire trap. Failure to remove it succesfully detonates it immediately. An unsuccessful dispel magic spell will not detonate the spell.
When the trap is discharged, there will be an explosion of five-foot radius from the spell's center. All creatures within this area must roll saving throws vs. spell. Damage is 1d4 points plus 1 point per level of the caster; half that total amount for creatures successfully saving. (Underwater, this ward inflicts half damage and creates a large cloud of steam.) The item trapped is not harmed by this explosion.
The caster can use the trapped object without discharging it, as can any individual to whom the spell was specifically attuned when cast (the method usually involves a keyword).
To place this spell, the caster must trace the outline of the closure with a stick of charcoal and touch the center of the effect. Attunement to another individual requiresa hair or similar object from the individual.
The material components are holly berries.