What method is primarily used for physical decontamination after exposure to OC?

The method primarily used for physical decontamination after exposure to oleoresin capsicum (OC), commonly known as pepper spray, is to wash the affected area with soap and water. When someone is exposed to OC, it can cause intense irritation, including a burning sensation and disorientation. Utilizing soap and water helps to break down the oil-based compounds in OC and effectively removes them from the skin or eyes.

The choices that involve using a vacuum, strobing the eyes, or covering the face do not address the need for decontamination directly. While strobing the eyes might provide some temporary distraction, it does not cleanse the irritant from the surface nor relieve the symptoms of exposure. Similarly, simply covering the face does not eliminate the substance and can even trap the irritant against the skin, worsening the situation. Thus, washing with soap is the best practice for decontaminating after exposure to OC.