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031-503-2001 (SL2) - Identify Chemical Agents Using M256-Series Chemical Agent Detector Kit

Standards: Identified chemical agents using an M256-series chemical agent detector kit without becoming a casualty.

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.

Identified chemical agents using an
M256-series chemical agent detector kit
without becoming a casualty.


1.   Perform before-operation preventive maintenance
checks and services (PMCS) according
to TM 3-6665-307-10.

2.   Prepare the kit for use.

Read all the instruction
cards in the kit.

Remove one sampler
detector from the kit, and read the
instructions printed on the bag.


not expose the sampler detector to
heavy rain or other forms of water. 
Test results could be tainted.

not touch the sampler detector test
Dirt and oil from your gloves
will cause test results to be tainted.

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.

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.

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.


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

Hold the sampler detector
with the test spots and the arrow
pointing up. 
Crush the four center ampules
(marked 3).

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.

Hold the sampler detector
with the arrow pointed down and your
thumb on the protective strip over
the middle test spot.

Swing the heater away
from the blister test spot.

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
Hold the sampler detector
to one side to avoid the vapor. 
Do not use the heater pads
to crush green ampules.


not use the heater pads to crush the
green ampules

Swing the heater and
the protective strip away from the
test spots.


not hold the sampler detector in
direct sunlight while exposing the
test spots, because test results could
be tainted

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

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.


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.

Bend the tab (marked 2)
over the lewisite detecting tablet,
and rub the bottom half of tab until
a mark is visible.

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.

Compare the blood agent
(round) test spot after about 10
minutes exposure time.

Yellow or orange
sometimes occur when no agent is

Pink or blue must be
present to indicate blood
Any combination of colors
or a rainbow effect that
includes pink or blue should be
considered as a positive blood
agent test.

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

Wait 3 minutes for the nerve-agent

NOTE.  Disregard
any small blue or blue-green areas
under the plastic rim of the nerve
agent spot.

M256: If a peach color develops,
a positive nerve test is

M256A1: If no color develops, a
positive nerve test is

4.   Report the results to your supervisor.

Dispose of the materials by one of the following methods:

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.

Dispose of contaminated
hazardous waste materials according
to FM 3-5.

6.   Perform after-operation PMCS according to TM

Ensure M8 detector paper is

Ensure there are at least
four sample-detectors in the kit.


Evaluate this task during a field exercise
or a tactical training session. The
contaminated area should be set up with
nerve and blister simulated agents. Use M256
training aid kits for training and
evaluation purposes.

Tell the soldier he will be
evaluated on his ability to perform operator
checks of the chemical agent detector kit,
to put the kit into operation using the
correct sequence while in MOPP 4, and to
identify agent(s) within the limitations of
the kit.




1.   Performed before-operation PMCS according to TM

2.   Prepared the kit for use.

3.   Tested for toxic-agent vapors.

4.   Reported the results to the supervisor.

5.   Disposed of expended or unserviceable kits.

6.   Disposed of hazardous waste materials.

7.   Performed after-operation PMCS.

Score the soldier GO if all
performance measures are passed. Score the
soldier NO GO if any performance measure is
failed. If the soldier fails, show him how
to do it correctly.











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