Station 3- Wait/ Interior Decon 

The objective of this station is to allow the DS2 to neutralize the chemical agent and to decontaminate the interior of the vehicle completely. Vehicles are moved to a concealed position. Vehicles will remain in station 3 for no less than 30 minutes. When you allow the DS2 to remain on the contaminated surface for 30 minutes, the amount of agent that will later desorb (off gas) will be significantly reduced. When there is a 30-minute contact time, there will be no resorption after decon operations for most chemical agents. However, studies suggest that HD vapor will desorb after decon, even if DS2 is allowed to remain for 30 minutes.

While the vehicle is held in this station for the DS2 to react completely, the driver inspects the interior of the vehicle for liquid contamination. The driver will be given M8 detector paper. If the driver identifies chemical contamination, he or she will be given decon supplies to decontaminate the interior of his or her vehicle. The best decon solution for use in the interior of vehicles is a 5 percent solution of HTH or STB. The driver wipes all reasonable accessible surfaces with a rag or sponge soaked in the HTH or STB solution. Do not attempt to decon areas where there is little likelihood of contamination (electrical assemblies, etc.).

CAUTION

Do not mix HTH or STB with DS2. If mixed, a violent reaction will occur.

Once interior decon is completed, the driver dismounts from the vehicle and proceeds to the start of the detailed troop decon (DTD). Having completed the DTD, the assistant driver mounts the vehicle and moves it to the next station. Drivers must exercise caution when entering or exiting the vehicle. A DS2-coated surface is slippery and DS2 may react with chemical protective footwear. Personnel should avoid stepping in DS2 and tracking it into the vehicle.

For radiological contamination, use an AN/ PDR 27-series radiac meter to decide the extent and location of contamination inside the vehicle. If there is contamination, figure out the intensity of the contamination inside of the vehicle. If the contamination has an intensity greater than 0.33 cGy (the negligible risk), the interior of the vehicle must be decontaminated. Use hot, soapy water to wash the contaminated areas. Use a sponge to mop up the water and the contamination. Table 6-6 is a planning guide for decon mixtures.

Station 4- Rinse The objective of this station is to remove the DS2 from the vehicle. The vehicle is sprayed with water

from top to bottom. Take care to rinse the undercarriage. This station uses approximately 200 gallons of water. Failure to remove all the DS2 from the vehicle may cause false positive readings at station 5. If high water pressure systems (M12A1 PDDA, M17 LDS) are not available, large volume water pumps (65-gpm pumps) should be used at this station.

Station 5- Check

The objective of this station is to check the completeness of the decon. This station determines whether the vehicle has a negligible risk or still has significant contamination remaining. Detection procedures will vary depending on the type of contamination. If significant contamination is found on the vehicle, the vehicle will be recycled to station 2 for chemical contamination or station 1 for radiological contamination.

Chemical The CAM is used to check for the presence of vapor from residual liquid contamination. A one bar or lower reading on the CAM indicates a negligible risk. Once the CAM indicates the presence of vapor contamination, M8 detector paper is used to verify the presence of liquid contamination. If it is suspected that both the CAM and M8 paper are producing a false positive reading, use an M256 chemical detector ticket to confirm or deny the presence of contamination. Table 6-7 is a list of common interference that can cause false positive readings on the CAM. If the vehicle has significant contamination remaining, recycle it.

There will be desorption of chemical agents from the surfaces after decontamination. On CARC-painted surfaces, the desorption of vapors will stop sooner than alkyd-painted surfaces. Consider this when checking decontaminated items for overall decontamination effectiveness.

Table 6-6.- Preparation of Decon Mixtures

Table 6-7.-

Common Interferences That Can Cause False Positive Readings on the CAM. Radiological Use the AN/ PDR-27-series to decide if any contamination remains. If there is contamination remaining, determine the intensity of the contamination inside and outside of the vehicle. If the contamination has an intensity greater that 0.33 cGy (the negligible risk), the vehicle is recycled to station 1.

Recycle Criteria The COC, together with the CBR officer, will establish the recycle criteria before the start of decon operations. The recycle criteria decides which vehicles return to station 1 after contamination is detected at station 5. If the unit has sufficient time and resources, any vehicle having more contamination than a negligible risk should be recycled. However, time and resources are usually limited and not all vehicles can be recycled. The recycle criteria is based on the weathering effects.