The Mount Kilimanjaro Western Breach is a gap, formed by the lava flow, on the western outer rim of Mount Kilimanjaro‘s main summit, Kibo.
Despite its moderate inherent risks, among experienced climbers the Western Breach is still a popular ascent route because it is very direct and more interesting than the two heavily frequented standard routes on the southeast face of Kibo.  
In September 2015, San Francisco resident Scott Dinsmore was killed by a boulder while hiking up from Arrow Glacier Camp.
Alternatively, it is possible for trekkers on most other routes to stay one night in the crater at the Crater Camp, allowing for extended time to explore the peak without the added risk of an assault via the Western Breach. 
It may be advisable to spend an additional night at Lava Tower Camp (4600m) to aid acclimatization before positioning to Arrow Glacier Camp (4800m) the day after, in preparation for the final night-time push to the summit.
Avoid being in the breach in windy conditions, as well as daylight hours, which may both increase the probability of rock fall. Ensure sufficient acclimatization and rest before entering the breach, so as to be able to move through it swiftly, minimizing exposure time to rock fall.