
49Industrial Accidents
These errors, therefore, can remain and eventually enough
such errors align to produce a chain of events leading to an acci-
dent or process failure. Effectively it is the duration or lifetime
of each latent error that makes this alignment or “Swiss cheese”
effect inevitable. Therefore, periodic, detailed “what if” audits
involving experts as well as production staff and documentation
and removal of latent errors are crucial (and sometimes missing)
steps in production facilities. These are sometimes incorporated
into safety auditing processes, but the level of detail needed to
pick up many latent errors in control systems ...