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Nerve Agents

The Occupational Safety and Health Act (OSH Act) requires employers to comply with hazard-specific safety and health standards. In addition, pursuant to Section 5(a)(1) of the OSH Act, employers must provide their employees with a workplace free from recognized hazards likely to cause death or serious physical harm. Emergency Preparedness Guides do not and cannot enlarge or diminish an employer's obligations under the OSH Act.

Emergency Preparedness Guides are based on presently available information, as well as current occupational safety and health provisions and standards. The procedures and practices discussed in Emergency Preparedness Guides may need to be modified when additional, relevant information becomes available or when OSH Act standards are promulgated or modified.

Because of recent terrorist events many workers have expressed concern about the possibility of a terrorist attack involving nerve agents. In 1995, twelve people were killed when the nerve agent sarin was released in the Tokyo subway system. The following frequently asked questions will help workers understand what nerve agents are and how they may affect their health and safety.

General Information

What are nerve agents?

Nerve agents are highly toxic chemicals called "organophosphates" that poison the nervous system and disrupt bodily functions which are vital to an individual’s survival. They were originally produced in a search for insecticides, but because of their toxicity, they were evaluated for military use.

What are the different forms of nerve agents and their properties?

Nerve agents, depending on their purity, are clear and colorless or slightly colored liquids and may have no odor or a faint, sweetish smell. They evaporate at various rates and are denser than air, so they accumulate in low areas. Nerve agents include tabun(GA), sarin(GB), soman(GD), and VX.

Why are we concerned about nerve agents as a terrorist’s weapon?

There are large stockpiles of nerve agents which, if obtained by terrorists, could be released using bombs, explosives, spray tanks, or rockets.

How long will aerosolized nerve agents persist in the environment?

The "G" agents tend to be volatile liquids which do not persist in the environment very long. The "VX" tends to be highly persistent and thus non-volatile. When compared to the "G" agents, "VX" is much more lethal and persistent. See the following table for more information:

Types and Characteristics Chemical Agents

		PERSISTENCE	PERSISTENCE		ENTRANCE
TYPE OF AGENT	SYMBOL	SUMMER	WINTER	RATE OF ACTION	VAPOR/AEROSOL	LIQUID
NERVE	GA, GB, GD	10 min-24 hr	2 hr-3 days	Very Quick	Eyes, Lungs	Eyes, Skin, Mouth

*ARMY FIELD MANUAL NO. 8-10-7. Health Service Support in a Nuclear, Biological, and Chemical Environment.

Health Effects

How do nerve agents affect people?

Nerve agents are highly toxic and rapidly affect exposed individuals. Nerve agents enter the body primarily through the respiratory tract, although they may be absorbed through the eyes or skin. In the liquid state, nerve agents are hazardous via skin or eye contact and through ingestion. Generally, all nerve agents are highly toxic and fast acting.

When a person is exposed to a nerve agent, the nerve agent, upon entering the body, inhibits the normal actions of acetylcholinesterase; a chemical within the body whose normal function it is to break down the chemical acetylcholine. Acetylcholine causes muscular contraction. What nerve agents do to acetylcholinesterase is inhibit it from breaking down acetylcholine which in turn causes violent muscle spasms.

What are the symptoms of nerve agent poisoning?

When an individual is exposed to low amounts of a nerve agent (as a gas or aerosol) the initial symptoms are a runny nose, contraction of the pupils, deterioration of visual accommodation, headache, slurred speech, nausea, hallucinations, pronounced chest pains, and an increase in the production of saliva. At higher doses, these symptoms are more pronounced. Coughing and breathing problems also begin to occur. The individual then may begin to go into convulsions possibly progressing to coma or death. At even higher doses, an exposed individual would almost immediately go into convulsions and die from suffocation because of the simultaneous shut-down of the nervous and respiratory systems.

See the following links for more information on health effects:

Sarin (GB). CDC Emergency Preparedness and Response (2003, April 3). This page includes links Fact Sheets, an Emergency Response Card, Medical Management Guidelines, and FAQ's about Sarin.
VX. CDC Emergency Preparedness and Response (2003, April 3). This page includes links to Fact Sheets, an Emergency Response Card, Medical Management Guidelines, and FAQ's about VX.
Tabun (GA). CDC Emergency Preparedness and Response (2003, March 13). This page includes links Fact Sheets, an Emergency Response Card, Medical Management Guidelines, and FAQ's about Tabun.
Soman (GD). CDC Emergency Preparedness and Response (2003, March 13). This page includes links Fact Sheets, an Emergency Response Card, Medical Management Guidelines, and FAQ's about Soman.

Controls

How do I protect myself from nerve agents?

If you are exposed to a nerve agent attack, move away from the impacted area quickly without passing through the contaminated area. It may be necessary to "shelter-in-place" if you can’t get out of a building or if the nearest place with clean air is indoors.

If available, a good way to protect yourself from nerve agents is to wear appropriate chemical protective clothing and respiratory protection. However, protective equipment does not always work against nerve agents. The effectiveness is determined by the materials of construction, the type and level of exposure, and duration of exposure.

What does it mean to "shelter in place?"

"Shelter in place" means to go indoors, close up the building, and wait for the danger to pass. If you are advised to shelter in place, close all doors and windows; turn off fans, air conditioners, and forced-air heating units that bring in fresh air from the outside; only recirculate air that is already in the building; move to an inner room or basement; and keep your radio turned to the emergency response network or local news to find out what else you need to do.

For additional information see the Shelter-in-Place Information Center.

What should I do if I have been exposed to a nerve agent?

If you have been exposed to a nerve agent, remove all clothing immediately and wash with copious amounts of soap and water. Seek emergency medical attention.

Is there any treatment for persons exposed to nerve agents?

Because nerve act rapidly, treatment must begin immediately after exposure or death may occur. A general antidote to nerve agents is a combination of atropine and a reactivator. Atropine protects against the excess of acetylcoline formed during nerve agent poisoning. The reactivator's job is to restore acetylcholinesterase to its normal functions. The degree of difficulty in combating the nerve agent depends greatly on the quantity and type of nerve agent.

Health care professionals use an auto-injector to inject a mixture of atropine and the reactivator into patients exposed to nerve agents. The auto-injector consists of the two active components which are injected into an exposed individual through the use of a very long needle. The auto-injector is usually injected into an individual's thigh or another area where the antidote can reach the heart relatively quickly.

Is there a medical test to show whether I've been exposed to nerve agents GA, GB, GD, or VX?

Yes, medical tests can determine whether you have been exposed to nerve agents. There are tests to measure degradation products of nerve agents in the urine, but these are not generally useful. A different kind of test measures the levels of a substance called cholinesterase in the blood. If these levels are less than half what they should be, and you were exposed to nerve gases, you may experience symptoms of poisoning. Cholinesterase levels in the blood can remain low for months after you have been exposed to nerve agents. Measurement of cholinesterase levels in blood is not specific for exposure to nerve agents.

Has the federal government made recommendations to protect worker health?

OSHA has not set occupational exposure levels for exposure to nerve agents. However, other government departments and agencies have published existing and proposed standards.

Summary of Chemical Agent Air Exposure Values Table 1. (2004, August 3), 87 KB PDF, 2 pages.
Summary of Multi-Media Chemical Agent Toxicity and Exposure Values Table 2. (2004, August 3), 206 KB PDF, 2 pages.
Guide for the Selection of Chemical Agent and Toxic Industrial Material Detection Equipment for Emergency First Responders. National Institute of Justice Guide 100-00 (Volumes I and II) (200, June). This guide for emergency first responders provides information about detecting chemical agents and toxic industrial materials and selecting equipment for different applications.
Guide for the Selection of Personal Protection Equipment for Emergency First Responders, NIJ Guide 102–00 (Volumes I, IIa, IIb, and IIc). National Institute of Justice Guide 102-00 (Volumes I, IIa, IIb, and IIc) (2002, November). The three parts to Volume II cover Respiratory Protection, Percutaneous Protection-Garments, and Percutaneous Protection-Apparel, respectively.
Guidelines for Mass Casualty Decontamination During a Terrorist Chemical Agent Incident. U.S. Army Soldier and Biological Chemical Command (SBCCOM) (2000, January), 847 KB PDF, 56 pages.
Acute Exposure Guideline Levels (AEGLs) Chemical List. U.S. Environmental Protection Agency (EPA). Use the name for the AEGL chemical or its corresponding CAS number to find AEGL information on this web site.
Medical Management Guidelines (MMGs) for Nerve Agents: Tabun (GA); Sarin (GB); Soman (GD); and VX. Agency for Toxic Substances and Disease Registry (ATSDR) (2004, May 24).
Training Products. U.S. Army Medical Research Institute of Chemical Defense, Chemical Casualty Care Division.

First Responders

How should first responders prepare for a release of nerve agents?

First responders should consider the possible impact of a release and potential exposure to nerve agents and address this in their health and safety plan (HASP). The safety and health plan should include guidelines such as: monitoring, detection, awareness training, personal protective equipment, decontamination, and medical surveillance of acutely exposed workers.

What equipment can first responders use to detect if a nerve agent is present?

The military has a number of devices to detect nerve agent vapor and liquid. The most portable of the vapor detectors are the M256A1 card or ticket and the Chemical Agent Monitor (CAM). The most simple liquid detectors are the M8 and M9 papers. Direct reading instruments that are available include specialized gas chromatographs (minicams) and ion mobility spectrometers such as the APD 2000. Since some of these detectors cannot adequately detect the agents at safe airborne levels, users should be trained in regards to the use and limitations of the detectors. Listed below is a table of military detection and monitoring equipment: Military Detection and Monitoring Equipment

Equipment	Agent	Sensitivity	Time	Cost	Operations/ Maintenance/ Limits	Notes
M-8 Paper	Nerve-G Nerve-VX Mustard-H Liquids only	100-µ drops 100-µ drops 100-µ drops	<=30 sec	$1 per book of 25 sheets	Disposable/ hand-held Dry, undamaged paper has indefinite shelf life	Chemical agent detector paper; 25 sheets/book and 50 booklets/box; potential for false positives.
M-9 Paper	Nerve-G Nerve-VX Mustard-H Liquids only	100-µ drops 100-µ drops 100-µ drops	<=20 sec	$5 per 10-m roll	Disposable/ hand-held 3-year shelf life Carcinogen	Adhesive-backed dispenser roll or books.
M-18A2 Detector Kit	Nerve-GB Nerve-VX Mustard-H, HN, HD, HT Lewisite-L, ED, MD Phosgene-CG Blood-AC Liquid, vapor, aerosol	0.1 mg/m³ 0.1 mg/m³ 0.5 mg/m³ 10.0 mg/m³ 12.0 mg/m³ 8.0 mg/m³	2—3 min	$360	Disposable tubes Hand-held	25 tests per kit; Detector tubes, detector tickets, and M-8.
M-256A1 Detector Kit	Nerve-G and VX Mustard-HD Lewisite-L Phosgene oxime-CX Blood-AC, CK Vapor or liquid	0.005 mg/m³ 0.02 mg/m³ 2.0 mg/m³ 9.0 mg/m³ 3.0 mg/m³ 8.0 mg/m³	15 min Series is longer AC--25 min	$140	Disposable/ Hand-held 5-year shelf life	Each kit contains 12 disposable plastic sampler-detectors and M-8 paper.
M-272 Water Test Kit	Nerve-G and VX Mustard-HD Lewisite Hydrogen cyanide	0.02 mg/l 2.0 mg/l 2.0 mg/l 20.0 mg/l	7 min 7 min 7 min 6 min	$189	Portable/ lightweight 5-year shelf life USN, USMC	Used to test raw or treated water; Type I and II detector tubes, eel enzyme detector tickets; Kit conducts 25 tests for each agent.
CAM Chemical Agent Monitor	Nerve-GA, GB, VX Blister-HD and HN Vapor only	0.03 mg/m³ 0.1 mg/m³	30 sec <=1 min	$7,500	Hand-held/portable battery operated 6—8 hours continuous use. Maintenance required.	Radioactive source. False alarms to perfume, exhaust paint, additives to diesel fuel.
ICAM Improved Chemical Agent Detector	Nerve-G and V Mustard-HD	0.03 mg/m³ 0.1 mg/m³	10 sec 10 sec	$7,500	4.5 pounds Minimal training	Alarm only; False positives common.
ICAM-APD Improved Chemical Agent Detector--Advanced Point Detector	Nerve-G Nerve-V Mustard-H Lewisite-L	0.1 mg/m³ 0.04 mg/m³ 2.0 mg/m³ 2.0 mg/m³	30 sec 30 sec 10 sec 10 sec	$15,000	12 pounds including batteries Low maintenance Minimal training	Audible and visual alarm.
ICAD Miniature Chemical Agent Detector	Nerve-G Mustard-HD Lewisite-C Cyanide-AC, CK Phosgene-CG	0.2—0.5 mg/m³ 10 mg/m³ 10 mg/m³ 50 mg/m³ 25 mg/m³	2 min (30 sec for high levels) 2 min 15 sec	$2,800	8 oz pocket-mounted 4 months service No maintenance Minimal training	Audible and visual alarm; Marines; No radioactivity.
M-90 D1A Chemical Agent Detector	Nerve-G, V Mustard Lewisite Blood Vapor only	0.02 mg/m³ 0.2 mg/m³ 0.8 mg/m³ N/A	10 sec 10 sec 80 sec	$16,000	15 lb. with battery Radioactive source exempt from licensing. Minimal training	Ion mobility spectroscopy and metal conductivity technology can monitor up to 30 chemicals in parallel. Alarm only.
M-8A1 Alarm Automatic Chemical Agent Alarm	Nerve-GA, GB, GD Nerve-VX Mustard-HD Vapor only	0.2 mg/m³ 0.4 mg/m³ 10 mg/m³	<=2 min <=2 min <=2 min	$2,555	Vehicle battery operated Maintenance required	Radioactive source (license required); Automatic unattended operation; Remote placement.
MM-1 Mobile Mass Spectrometry Gas Chromatograph	20—30 CWA Vapor	<10 mg/m² of surface area	<=45 sec	$300,000 military $100,000 civilian	Heater volatizes surface contaminants.	German "Fuchs" (FOX Recon System/Vehicle)
RSCAAL M-21	Nerve-G Mustard-H Lewisite-L Vapor	90 mg/m³ 2,300 mg/m³ 500 mg/m³		$110,000	Line-of-sight dependent 10 year shelf life 2-person portable tripod	Passive infrared energy detector 3 miles; Visual/ audible warning from 400 meters
SAW Mini-CAD	Nerve-GB Nerve-GD Mustard-HD Vapor	1.0 mg/m³ 0.12 mg/m³ 0.6 mg/m³	1 min 1 min 1 min 1 pound No calibration	$5,500	Minimal training Field use	Alarm only; False alarms from gasoline vapor, glass cleaner.
ACADA (XM22)	Nerve-G Mustard-HD Lewisite Vapor	0.1 mg/m³ 2 mg/m³ --	30 sec 30 sec --	$8,000	Vehicle mounted, battery powered Radioactive source (license required) Minimal training	Audible alarm; Bargraph display--low, high, very high.
Field Mini-CAMs	Nerve-G, V Mustard-H Lewisite-L	<0.0001 mg/m³ <0.003 mg/m³ <0.003 mg/m³	<5 min <5 min <5 min	$34,000	Designed for field industry monitoring (10 lb.) 8 hours training 24 hour/7 day operations	Plug-in modules increase versatility; Threshold lower than AEL.
Viking Spectratrak GC/MS	Nerve-G, V Mustard-HD Many others	<0.0001 mg/m³ <0.003 mg/m³	<10 min <10 min	$100,000	Field use, but 85 pounds Needs 120v AC, helium 40 hours training	Lab quality analysis; Library of 62,000 chemical signatures.
HP 6890 GC with flame photometric detector	Nerve-G, V Mustard-HD Many others	<0.0001 mg/m³ <0.0006 mg/m³	<10 min <10 min	$50,000	Not designed for field use Gas, air, 220v AC 40 hours training	State-of- the-art gas chromatograph; Used by CWC treaty lab.

Reference from National Research Council’s Chemical and Biological Terrorism: Research and Development to Improve Civilian Medical Response.

What personal protective equipment (PPE) should first responders use?

When an active release is occurring, or the release has stopped but there is no information about the duration of the release or the airborne concentration of nerve agents, don level A protection. The requirement of OSHA’s Hazardous Waste Operations and Emergency Response (HAZWOPER) standard (29 CFR 1910.120(q)) provides additional information for responding to hazardous substance releases including nerve agents.

For additional information see CBRN Personal Protective Equipment Selection Matrix for Emergency Responders - Nerve Agents.

Healthcare Workers

How should healthcare workers prepare to respond to a nerve agent release?

Healthcare facilities should have a health and safety plan in place that addresses the possibility of receiving patients exposed to nerve agents from a terrorism event. The document "OSHA Best Practices for Hospital-Based First Receivers of Victims" contains practical information developing a emergency management plan and includes victim decontamination, personal protective equipment, and employee training.

How do I decontaminate a patient?

Healthcare professionals should don appropriate gloves and respiratory protection and then remove contaminated clothing from victim and thoroughly wash exposed areas with soap and water. Healthcare professionals should also wash hands after removing any protective gloves and any other potentially exposed body surfaces.

Last Updated: 01 March 2005

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