36. You have water washed your cargo tanks using the fixed machines. What should you do before using portable machines to clean areas screened from the wash of the fixed machine by structural members?

Ventilating the tank removes electrostatically charged mist, which can ignite flammable vapors. Water washing creates a fine mist that can become electrostatically charged, and introducing portable equipment increases the risk of static discharge. Therefore, ventilation is necessary before using portable machines.