Final answer:
Option C. Dusts, mists, and fumes represent an eye hazard because their small size allows them to penetrate the eye easily and unknowingly, leading to irritation, and in some cases, more serious health issues.
Step-by-step explanation:
Dusts, mists, and fumes are considered a serious eye hazard primarily because they are often too small to see, which means they can easily enter and irritate the eye without notice. Tiny particles like PM2.5 are responsible for visibility impairment and can also cause harm when they come into contact with the eyes. In occupational settings, the risk of exposure to these substances is heightened, and workers may be subject to health effects including eye irritation, damage to the central nervous system, and possibly cancer.
In addition, certain substances like volatile organic compounds (VOCs) can cause irritation to the eyes, nose, and throat. Nitrogen dioxide (NO2) is another compound that, even though it is colorless and odorless, results in eye irritation and potentially aggravates respiratory conditions.