Approximately how much external contamination on a person can be removed by taking off outer clothing?

Removing outer clothing can effectively eliminate a significant amount of external contamination due to the nature of how such contaminants typically adhere to surfaces. Outer clothing often acts as a barrier, capturing and holding particles or substances that may have come into contact with the skin.

In scenarios involving contamination, clothing can trap various materials, including radioactive particles or chemical agents. When an individual removes outer layers, they effectively displace and dispose of a large proportion of these contaminants, particularly those that have settled on the fabric. Research and practical experience in contamination control have demonstrated that the removal of clothing can lead to the decontamination of up to 90% of the contaminating material. This high percentage reflects the assumption that the most accessible and superficial contamination is primarily found on clothing rather than deeply embedded in the skin or in other layers.

Although complete decontamination is not always achievable through clothing removal alone—since some contaminants may adhere strongly or may have penetrated into the underlying skin—the significant reduction in contamination highlights the importance of prompt clothing removal as a primary initial response to exposure. This makes the option indicating that approximately 90% of external contamination can be removed by taking off outer clothing the most accurate in this context.