Final answer:
The primary route of exposure of vesicant agents is the skin, which is most susceptible to the harmful effects of these chemicals, such as blisters and burns.
Step-by-step explanation:
The primary route of exposure of vesicant agents is the skin. Vesicant agents, when in contact with the skin, can cause severe blisters, chemical burns, and tissue damage. Although respiratory exposure can also occur, particularly with vaporized vesicants, the skin is regarded as the most common and immediate route of exposure. It is crucial for individuals working with or around vesicant agents to wear appropriate protective gear to prevent skin contact. In addition to the skin, vesicants can also enter the body through other routes such as the eyes (via the conjunctiva) or wounds, leading to localized or potentially systemic effects.