If flammable vapors have penetrated a gas free space, which of the following actions would be the most hazardous to perform?

Correct Answer: Option A — Opening switches in the space to de-energize circuits.

Opening an electrical switch creates a spark that can ignite flammable vapors present in the atmosphere. In a gas-freeing operation, all electrical equipment must be de-energized from a remote location before entering or manipulating switches within the space to prevent an explosion caused by electrical arcing.