I am not aware of any incidents, but then my experience is largely limited to one company, plus what I happen to read about. You might have better luck by asking your company's insurance carrier, who might have access to a larger set of industry incidents. Of course, they also have an interest in convincing you to spend lots of your money to minimize their potential for incurring a loss! There are also industry databases that can be used (CCPS, Institution of Chemical Engineers in the U.K.), but you have to pay to get access to most of them, and I obviously don't have access. It might also be worth while asking somebody at NFPA, Bob Benedetti might be a good place to start.