Infantry Drills

I-8: Unmasking with M256/M256A1 Detector Kit

Previous: Section II: Unmasking Procedures

I-8. If an M256/M256A1 detector kit is available, use it to supplement unmasking procedures. The kit does not detect all agents; therefore, proper unmasking procedures, which take approximately 15 minutes, must still be used. If all tests with the kit (to include a check for liquid contamination using M8 detector paper) have been performed and the results are negative, use the following procedures:

  • The senior person should select one or two Soldiers to start the unmasking procedures. If possible, they move to a shady place; bright, direct sunlight can cause pupils in the eyes to constrict, giving a false symptom.
  • Selected Soldiers unmask for 5 minutes, then clear and reseal masks.
  • Observe the Soldiers for 10 minutes. If no symptoms appear, request permission from higher headquarters to signal “ALL CLEAR.”
  • Watch all Soldiers for possible delayed symptoms. Always have first-aid treatment immediately available in case it is needed.

Next: I-9: Unmasking without M256/M256A1 Detector Kit

Go Back To: U.S. Army FM 3-21.8: The Infantry Rifle Platoon and Squad