An interlock mechanism (51, 52) for selectively retaining a door (40; 340; 440) of a safety cabinet (30; 330; 430) in a closed position, the interlock mechanism (51, 52) including a mounting element (201, 205), a fusible link (310, 314; 604, 608), a catch (272, 280), and a biasing mechanism (203, 207), wherein: the fusible link (310, 314; 604, 608) is connected to both the mounting element (201, 205) and the catch (272, 280); the catch (272, 280) is movable over a range of travel between a retracted position and an interlocked position; the biasing mechanism (203, 207) arranged with the catch (272, 280) to urge the catch (272, 280) to the interlocked position; and the fusible link (310, 314; 604, 608) is connected to the catch (272, 280) such that the catch (272, 280) is constrained from moving to the interlocked position by the fusible link (310, 314; 604, 608), characterized in that the catch (272, 280) is moveable to an intermediate extended position, the intermediate extended position being disposed between the retracted position and the interlocked position, the biasing mechanism (203, 207) is arranged with the catch (272, 280) to urge the catch (272, 280) toward the intermediate extended position under ambient temperatures below a fuse threshold for the fusible link (310, 314; 604, 608), the fusible link (310, 314; 604, 608) being connected to the catch (272, 280) such that the catch (272, 280) is prevented from moving from the intermediate extended position to the interlocked position until the fusible link (310, 314; 604, 608) melts at a predetermined temperature, and the fusible link (310, 314; 604, 608) is configured to melt at the predetermined temperature to thereby allow the biasing mechanism (203, 207) to move the catch (272, 280) from the intermediate extended position to the interlocked position. the fusible link (310, 314; 604, 608) is connected to both the mounting element (201, 205) and the catch (272, 280); the catch (272, 280) is movable over a range of travel between a retracted position and an interlocked position; the biasing mechanism (203, 207) arranged with the catch (272, 280) to urge the catch (272, 280) to the interlocked position; and the fusible link (310, 314; 604, 608) is connected to the catch (272, 280) such that the catch (272, 280) is constrained from moving to the interlocked position by the fusible link (310, 314; 604, 608), characterized in that the catch (272, 280) is moveable to an intermediate extended position, the intermediate extended position being disposed between the retracted position and the interlocked position, the biasing mechanism (203, 207) is arranged with the catch (272, 280) to urge the catch (272, 280) toward the intermediate extended position under ambient temperatures below a fuse threshold for the fusible link (310, 314; 604, 608), the fusible link (310, 314; 604, 608) being connected to the catch (272, 280) such that the catch (272, 280) is prevented from moving from the intermediate extended position to the interlocked position until the fusible link (310, 314; 604, 608) melts at a predetermined temperature, and the fusible link (310, 314; 604, 608) is configured to melt at the predetermined temperature to thereby allow the biasing mechanism (203, 207) to move the catch (272, 280) from the intermediate extended position to the interlocked position. the catch (272, 280) is moveable to an intermediate extended position, the intermediate extended position being disposed between the retracted position and the interlocked position, the biasing mechanism (203, 207) is arranged with the catch (272, 280) to urge the catch (272, 280) toward the intermediate extended position under ambient temperatures below a fuse threshold for the fusible link (310, 314; 604, 608), the fusible link (310, 314; 604, 608) being connected to the catch (272, 280) such that the catch (272, 280) is prevented from moving from the intermediate extended position to the interlocked position until the fusible link (310, 314; 604, 608) melts at a predetermined temperature, and the fusible link (310, 314; 604, 608) is configured to melt at the predetermined temperature to thereby allow the biasing mechanism (203, 207) to move the catch (272, 280) from the intermediate extended position to the interlocked position.