Pharmaceutical Powder Dryer Fire and Explosion

An operator had tested dryer samples on a number of occasions. After the last sampling, he closed the manhole cover, put the dryer under vacuum, and started rotation of the dryer. A few minutes later an explosion and flash fire occurred, which self-extinguished. No one was injured. Investigations revealed that after 

After this incident, the following precautions were instituted to prevent similar incidents from occurring in the future  

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