True Charlie, I should have said most of the time...

The Wetterhahn case was mentioned in the original comment thread (or one of the articles linked from the original post) and was so shocking that permanent changes in regulations and practice occurred.

More mundane and work-a-day 'early failures' here...

http://pipeline.corante.com/archives/2012/02/16/when_reagent...

PS: Posting this from near the site of a biological failure that claimed two lives and (I gather) inspired one novel...

https://en.wikipedia.org/wiki/Janet_Parker