A stowage container including a barrier such as a door or access panel and a breach detector for monitoring and/or detecting a breach of the barrier. The breach detector includes an indicator assembly having a slot that can be positioned between, and defined by, a front panel and a back panel of the barrier, and an indicator within the slot. The indicator assembly further includes a retainer that maintains the indicator in a first state when the barrier is in a first position (e.g., closed or sealed) and which releases the indicator into a second state when the barrier moves from the first position to a second position (e.g., open or breached). Upon returning the barrier to the first position, the indicator remains in the second state until the indicator reset to the first state.