Which of the following is a primary route of toxic material entry through the skin?

The primary route of toxic material entry through the skin is absorption. This process occurs when substances come into contact with the skin and penetrate its layers, potentially entering the bloodstream. The skin can absorb various chemicals, toxins, and other harmful substances, depending on their chemical properties, the condition of the skin, and the duration of contact.

While inhalation, injection, and ingestion are significant routes of exposure for toxic materials, they do not specifically focus on the skin's ability to absorb substances directly. Inhalation refers to breathing in toxins, injection involves a sharp object puncturing the skin to deliver toxins, and ingestion occurs when substances are taken in through the mouth. In contrast, absorption highlights the skin's role as a barrier and its vulnerability to certain chemicals that can cause harm upon contact, making it a critical route of exposure that requires attention in fire and safety inspections.