From AIChE's Center for Chemical Process Safety, the "Process Safety Beacons" so far this year:

Hydrate Hazards - "When a hydrate forms it can plug piping, instrument connections, valves, and other equipment causing process upsets which may be hazardous. ... Clearing a blockage from hydrate formation could be a routine or non-routine work activity that is hazardous if not done properly."

Still Overflowing Tanks! - "With all of the complex operations going on in many process facilities, it is surprising that putting more material into a tank than will fit is a frequent contributor to major incidents."

Safety Device or Control Device? - "Supervisors decided that the operator could be given other work to do while the tank was filling since there was a high level shutdown. No management of change review was done. A device that was intended to be a second layer of protection became the primary control. When the high level instrument failed, there was nobody in the area and the spill was actually larger."

Plugged Flame Arrester Causes Explosion - "The flame arrester on an oil tank was corroded and plugged with deposits. This resulted in the tank 'breathing' through a sample hatch at the tank rather than through the flame arrester as intended. When it was hot, during the day, vapors would exit the tank through the hatch."

More Repeat Incidents! - "If you use any hazardous materials, or if your process operates at hazardous conditions, you should understand what incidents have happened in the past with the materials and process conditions in your plant."