Which of the following is NOT considered a primary route of pesticide exposure for applicators?

The option identified is not considered a primary route of pesticide exposure for applicators because primary routes generally refer to the main ways through which substances can enter the body and cause potential harm.

Swallowing, direct skin contact, and inhalation are the traditional primary routes of exposure. When pesticides are inadvertently ingested, they enter the gastrointestinal system, which can lead to systemic effects. Skin exposure can occur through either dermal contact or absorption of pesticides, making it a significant concern because of the skin's ability to absorb certain chemicals. Inhalation is another critical route, where airborne particles or vapors can be breathed in, directly affecting the respiratory system.

On the other hand, contact through vision—while it can certainly pose a risk in specific scenarios—is not recognized as one of the primary exposure pathways. Vision contact typically refers to the possibility of getting pesticides in the eyes, which can lead to irritation or other issues but does not have the same widespread systemic effects as the other routes.

Therefore, the correct answer reflects a more nuanced understanding of exposure routes that are central to pesticide safety for applicators.