DETECTION OF TOXIC CHEMICAL AGENTS

It is difficult, and sometimes impossible, to identify chemical agents by sight, smell, or other sensory impressions. This method is quite unreliable, and it can be fatal. Some toxic agents are so deadly and so quick acting that one brief skin contact or one smalI whiff of vapor can cause immediate death.

Various devices are available to detect and identify chemical agents. Table 9-2 lists various chemical agents and which detection devices may be used to detect the individual agent. Most of these devices indicate the presence of chemical agents by color changes that are chemically produced. Some of the detection devices used in the Navy are discussed in the following sections.

Chemical Agent Detection Paper

Two types of chemical agent detection paper are being used in the Navy at the present time- the M-8 and the M-9. The M-9 paper is relatively new, and it supplements the M-8 paper. The M-9 paper does not replace the M-8 paper. Both types of paper are requisitioned separately through the supply system.

M-8 PAPER.- The M-8 chemical agent detection paper (fig. 9-2) is issued in a book of 25 split sheets (50 separate responses). It is chemically treated, dye impregnated, and perforated for easy removal. This paper detects the

Figure 9-2.-Paper, chemical agent detector, MB. 9-13

Table 9-3.-M-8 Paper Color Comparison Chart

presence of liquid V agents, G agents (nerve), and H agents (blister/mustard). When the M-8 paper is brought in contact with the suspected chemical agent, the chemicals in the paper react with the agent to produce specific color changes. The sheet of paper is then matched to the color comparison chart printed on the inside front cover of the M-8 book. The color response for M-8 paper is listed in table 9-3. Liquid droplets as small as 125-200 microns will produce a color change that is detectable by the naked eye. Response time is approximately 20 seconds.

NOTE: Certain agents give a red-brown color response, which is intermediate between the typical H and the typical G colors.

When using the M-8 paper, follow these procedures:

1. Detach a sheet of detector paper from the book and attach it to your clothing, or place it on a surface so that it can be exposed to drops or liquid splash of chemical agents. Use masking tape or any other available means to secure the paper in place.

2. If colored spots appear, put on your protective mask. Be prepared to take proper medical action if symptoms appear.

3. Compare the colored spots with the colors on the inside cover of the detector paper book to determine what type of agent is present.

4. The paper may also be used to detect liquid contamination by placing the paper in contact with the suspect surface. A color change similar to that shown on the inside cover indicates the presence of chemical agents. This paper will NOT detect gases or vapors.

M-9 PAPER.- The new M-9 (fig. 9-3) detector paper detects nerve agents (G and V) and blister agents (H and L) in the liquid state. The paper is sensitive to droplets as small as 100 microns and responds in approximately 10 seconds or less. The response time increases at temperatures below freezing. High temperatures

of 160F or above may cause a red color to appear, thus producing a false reading. The use of the M-9 detector paper is limited to agents in the liquid state; it will not detect chemical agent vapors. The M-9 detector paper has no agent specificity; the red color appears for all detectable

agents.

The M-9 liquid agent detector paper is issued by the roll and is 30 feet long and 2 inches wide. It has a Mylar film backing that has adhesive and release paper on the reverse side. The roll comes in a cardboard dispenser that has a serrated metal edge for cutting. A moistureproof, resealable bag is provided for storing the dispenser after it is

removed from its original shipping package.

When you open the shipping package (fig. 9-3, view A), remove the dispenser and the plastic storage bag. Save the plastic storage bag and discard the shipping package. Immediately write or stamp the current date on the dispenser. This date will be the base line to determine the useful life of the M-9 detector paper. Remove the cutter

edge protector and throw the protector away.

WARNING: The M-9 detector paper dye may cause cancer, but because very little is used, the risk is small, Always wear protective gloves when touching the detector paper. Do NOT place the detector paper in or near your mouth or on your skin.

To remove the M-9 detector paper from the dispenser (fig. 9-3, view B), use the following procedures:

1. Start the olive drab (OD) paper strip through the slot by applying a little finger pressure with the thumb or finger.

2. Hold the detector paper strip between the forefinger and thumb of one hand and the OD paper strip between the forefinger and thumb of the other hand. Pull enough of the detector paper out through the slots for the intended use. (Pull the detector paper strip and the OD paper strip at the same time.)

Figure 9-3.-M-9 chemical agent detector paper.

3. After you pull both of the paper strips through the slots, cut the detector paper half way by pulling the strip down on the cutting edge.

4. Lift the detector paper strip up off the cutting edge, and then pull both of the strips out a little further, about 1 inch.

5. Tear through the remaining half of the detector paper strip.

6. Tear off the OD paper strip, but leave enough paper sticking out to be ready for your next use.

To attach the M-9 detector paper to equipment, use the following procedures:

1. Attach the detector paper to equipment and bulkheads at locations where it can be seen easily. Wrap the detector paper around some part of the equipment where it will not get stepped on. To help make it easier to remove the detector paper, fold 1 inch of the paper back over (adhesive side to adhesive side) to form a tab. Remember to keep the paper away from hot surfaces and direct sunlight. Heat may cause the detector paper to turn red and cause false readings.

2. To attach the detector paper to flat surfaces, place the paper on the surface. Cover the detector paper with the OD paper strip and

press the detector paper into date. Be sure to. make a tab, as mentioned above, to help make it easy to remove the detector paper when required.

To check the surface of an area for liquid chemical agent contamination, take a piece of the detector paper and blot the surface around the suspected contaminated area. Do not rub or scrape the detector paper across rough surfaces. Scuff marks will cause false readings. If spots on the paper appear pink, red, red-brown, red-purple, or any shade of red, take protective actions and assume that you have been exposed to a liquid chemical agent.

Do not check the detector paper under a red light because you will not be able to see the liquid chemical agent red spots. Personnel who are color-blind should not check the detector paper for red spots. Blue, yellow, green, gray, or black spots are caused by humidity, not by liquid chemical agents.

Detector paper strips that show false positive readings need to be replaced with a fresh strip. False positive readings can be caused by the following factors: l Temperatures above 125F

l Scuffs l Cleaning compounds l DS-2 decontaminating agent l Gasoline l Grease l Hydraulic fluid and brake fluid . Insect repellent/spray l Lubricating oil l Ethylene glycol (pure antifreeze)

The detector paper will work in rain, snow,

and sleet. However, the reaction to agents is slower when the detector paper is soaked. When the surfaces are wet, attach the detector paper tighter than usual to prevent it from slipping. Temperatures around 32F slow down the speed that the paper will turn red. It may take the paper several minutes to show a color change.

When the dispenser is not in use, place it in the plastic storage bag to prevent contamination of the detector paper. Squeeze out the air before sealing the plastic storage bag. If the discard date or the useful life date has passed, replace the detector paper with a new, unopened roll.