In the caution making the scene safe mnemonic, which letter corresponds to Obstruction?

• A. D
• B. R
• C. O
• D. W

Answer: (C)

In this mnemonic, Obstruction is the factor you must identify to keep the scene safe; it refers to anything that blocks access, egress, or a clear path for responders and evidence collection. The letter associated with Obstruction is O, because Obstruction starts with O. So the correct choice is the one linked to O. Think of examples like a vehicle blocking a doorway, debris across a corridor, or a locked exit that could impede movement. Recognizing Obstruction early lets responders address it before moving on to other safety checks. The other letters in the set correspond to different aspects of scene safety, so they do not represent Obstruction.