Static electricity from gas and water jets

On a number of occasions people have received a mild electric shock while using a carbon dioxide fire extinguisher. The gas jets from the extinguishers contain small particles of solid carbon dioxide, so a charge will collect on the horn of the extinguisher and may pass to earth via the hand of the person who is holding the horn. 

A few years later carbon dioxide was injected into an underground tank containing Jet fuel as a tryout of a fire-fighting system. The tank blew up, killing 18 people who were standing on top of the tank. In this case the discharge may have occurred from the cloud of carbon dioxide particles. 

The water droplets from steam Jets are normally charged, and discharges sometimes occur from the Jets to neighboring grounded pipes. These discharges are of the corona type rather than true sparks and may be visible at night they look like small flames [2]. 

A glass distillation column cracked, and water was sprayed onto the crack. A spark was seen to Jump from the metal cladding on the insulation. which was not grounded, to the end of the water line. Although no ignition occurred in this case, the incident shows the need to ground all metal objects and equipment. They may act as collectors for charges from steam leaks or steam or water Jets. 

Most equipment is grounded by connection to the structure or electric motors. But this may not be true of insulation cladding, scaffolding, 

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