biggest stuff up you have done at work

[Hitman]

A few years ago i was working at Co*kburn Cement in W.A, and my job was to blend the special cement mixes as dry powder and then pump it into a silo using compressed air and a series of valves an pipes, well, I forgot to change one of the valves and ended up pumping 18 tonnes of dry cement powder into the wrong silo, unfortunately there was already a different type of cement powder in there already, so they had to hire a huge truck mounted vacuum and send a guy in through the top, hanging in a harness to vacuum it all out. Never got in trouble, and barely a word was spoken about it.