Identify Chemical Agents
Using M256-Series Chemical Agent Detector Kit
031-503-2001
Conditions: Given a tactical environment or a
simulated chemically (nerve and blister)
contaminated area and M256-series chemical agent
detector kit, protective mask, mission-oriented
protection posture (MOPP) gear or chemical
protective ensemble, watch, TM 3-6665-307-10,
and FM 3-5.
Standards: Identified chemical agents using an
M256 series chemical agent detector kit without
becoming a casualty.
References: FM 3-5 and TM 3-6665-307-10
Risk Assessment: Low
PERFORMANCE STEPS
1. Perform before-operation preventive
maintenance checks and services (PMCS)
according to TM 3-6665-307-10.
2. Prepare the kit for use.
a. Read all the instruction cards in the kit.
b. Remove one sampler detector from the kit, and
read the instructions printed on the bag.
WARNING
Do not expose the sampler detector to heavy rain
or other forms of water. Test results could be
tainted.
Do not touch the sampler detector test spots. Dirt
and oil from your gloves will cause test results to
be tainted.
c. Remove the sampler detector from the bag (save
the bag and use the instructions printed on the
outside). Discard the sampler detector if there are
broken or missing ampules, missing spots, or
crushed reagent channels, or if the blood agent test
spot is pink.
3. Test for toxic-agent vapors.
a. Swing out the heater and remove and save the
two heater pads (used for breaking glass ampules).
Swing the heater back in. Keep the protective strips
over the spots.
b. Remove the pull tab (marked 1) to expose the
lewisite detecting tablet. Bend the tab (marked 2)
over the lewisite detecting tablet, and rub the upper
half of the tab until a mark is visible.
WARNING
Before breaking the glass ampules (except heater
ampules), place one heater pad on each side of the
sampler detector, covering the ampule to be
broken. The pads will prevent pieces of glass from
cutting your gloves and hands.
c. Hold the sampler detector with the test spots
and the arrow pointing up. Crush the four center
ampules (marked 3).
d. Turn the sampler detector so the arrow points
down. Use the heater pads to squeeze the
ampules, forcing liquid through the formed
channels into the test spots.
e. Hold the sampler detector with the arrow pointed
down and your thumb on the protective strip over
the middle test spot.
(1) Swing the heater away from the blister test
spot.
(2) Activate the first heater ampule (marked 4)
by crushing one green ampule, swing the heater
back over the test spot, and leave it in place for 2
minutes. Hold the sampler detector to one side to
avoid the vapor. Do not use the heater pads to
crush green ampules.
WARNING
Do not use the heater pads to crush the green
ampules
(3) Swing the heater and the protective strip away
from the test spots.
WARNING
Do not hold the sampler detector in direct sunlight
while exposing the test spots, because test results
could be tainted
f. Expose the test spots to air (shield them from
direct sunlight) for 10 minutes. Lay the sampler
detector down or hold it by the hinged protective
strip.
g. Crush the second green ampule (marked 4) after
10 minutes and immediately swing the heater over
the blister test spot Swing the heater away from
the test spot after 1 minute.
WARNING
Do not use the heater pads to crush the green
ampules.
h. Hold the sampler detector with the arrow
pointing down and the test spots exposed. Use the
heater pads to crush the remaining ampules
(marked 5). Wet the test spots by squeezing the
ampules and forcing liquid onto them.
i. Bend the tab (marked 2) over the lewisite
detecting tablet, and rub the bottom half of tab
until a mark is visible.
j. Turn the sampler detector upside down, and
compare the colors of the test spots (including the
lewisite tab) with those shown on the sampler
detector.
(1) Compare the blood agent (round) test spot after
about 10 minutes exposure time.
(a) Yellow or orange sometimes occur when no
agent is present.
(b) Pink or blue must be present to indicate blood
agents. Any combination of colors or a rainbow
effect that includes pink or blue should be
considered as a positive blood agent test.
(2) Compare the lewisite test after about 10 minutes
exposure time. Look very closely; at low
concentrations, the color change may be very slight.
Note. Blister agents (H and CX) develop color
immediately after all ampules are broken.
(3) Wait 3 minutes for the nerve-agent test.
NOTE. Disregard any small blue or blue-green
areas under the plastic rim of the nerve agent spot.
(a) M256: If a peach color develops, a positive
nerve test is indicated.
(b) M256A1: If no color develops, a positive nerve
test is indicated.
4. Report the results to your supervisor.
5. Dispose of the materials by one of the following
methods:
a. Dispose of expended or unserviceable materials
according to Federal, state, and local laws; military
regulations and publications; host nation laws (if
more restrictive than U.S. laws); and the local
standing operating procedures (SOP). As a
minimum, place used decontaminating materials in
a sealed plastic bag and label it with the contents.
b. Dispose of contaminated hazardous waste
materials according to FM 3-5.
6. Perform after-operation PMCS according to TM
3-6665-307-10.
a. Ensure M8 detector paper is present.
b. Ensure there are at least four sample-detectors
in the kit.