When the employees of a restaurant attended a fire safety seminar, they watched a fire official demonstrate the proper way to operate an extinguisher.
"Pull the pin like a hand grenade," he explained, "then depress the trigger to release the foam."
Later an employee was selected to extinguish a controlled fire in the parking lot.
In her nervousness, she forgot to pull the pin.
The instructor hinted, "Like a hand grenade, remember?"
In a burst of confidence she pulled the pin and hurled the extinguisher at the blaze.
In the heat the ctclinder exploded killing the fireman.