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Chemical Datasheet


6.1 - Poison
Chemical Identifiers | Hazards | Response Recommendations | Physical Properties | Regulatory Information | Alternate Chemical Names

Chemical Identifiers

CAS Number - Chemical Abstracts Service registry number. Unique identification number assigned to this chemical by the American Chemical Society.

UN/NA Number - The United Nations-North America number (also called UN number or DOT number). 4-digit number identifying an individual chemical or group of chemicals with similar characteristics. Required on shipping papers; often shown on placards or labels. This numbering system was developed by the U.S. Department of Transportation, and then became the UN standard system for classifying hazardous materials.

DOT Hazard Label - U.S. Department of Transportation hazard warning label for the chemical (such as flammable liquid or corrosive). This label must be displayed on shipped packages, railroad tank cars, and tank trucks according to specifications described in 49 CFR 172.

CHRIS Code - 3-letter code used by the U.S. Coast Guard to identify individual chemicals included in its CHRIS (Chemical Hazards Response Information System) manual.

NFPA 704 - Text description of the diamond-shaped placard, which contains codes indicating the level of the chemical's health, flammability, and instability hazards, along with special hazards such as water- and air-reactivity. See a guide to the NFPA diamond.

General Description - Brief description of the chemical's general appearance, behavior, and hazardousness.

List of data sources.
CAS Number UN/NA Number DOT Hazard Label CHRIS Code
  • 541-25-3
  • Poison
NFPA 704
data unavailable
General Description
When pure, a colorless oily liquid solidifying at -13°C. Impurities cause colors ranging from brown to violet. Faint odor of geranium. Irritating to the eyes and mucous membranes at concentrations below the threshold of odor. Very toxic; used as a war gas. Produces severe vesication (blistering) even through rubber (Merck); absorbed through the skin to produce seven systemic effects. Antidote: dimercaprol (British Anti-Lewisite). Prolonged exposure of container to fire or intense heat may result in violent rupturing and rocketing of container.


Reactivity Alerts - Special alerts if the chemical is especially reactive (see list of reactivity alerts).

Air & Water Reactions - Special alerts if the chemical reacts with air, water, or moisture.

Fire Hazard - Description of the chemical's fire hazards (such as flammability, explosion risk, or byproducts that may evolve if the chemical is burned).

Health Hazard - Description of the chemical's health hazards (such as toxicity, flammability, or corrosivity).

Reactivity Profile - Description of the chemical's potential reactivity with other chemicals, air, and water. Also includes any other intrinsic reactive hazards (such as polymerizable or peroxidizable).

Reactive Groups - List of reactive groups that the chemical is assigned to, based on its known chemistry. Reactive groups are categories of chemicals that react in similar ways because their chemical structures are similar. Reactive groups are used to predict reactivity when you add a chemical to MyChemicals. Read more about reactive groups.

Potentially Incompatible Absorbents - Absorbents are products that can be used to soak up liquids from spills. However, some absorbents can react with particular chemicals (that is, they are incompatible), so caution should be used in selecting the correct absorbent for your situation. This section provides a list of potentially incompatible absorbents that have been known to react with liquids assigned to one or more of the reactive groups listed on this datasheet. Read more about absorbents, including situations to watch out for.

List of data sources.
Reactivity Alerts
Air & Water Reactions
Slowly decomposed by water.
Fire Hazard
(Non-Specific -- Arsenic Compound, Liquid, n.o.s.) Container may explode in heat of fire. Fire may produce irritating and poisonous gases. Hydrolyzed by alkalies; neutralized by sodium hypochlorite. (EPA, 1998)
Health Hazard
Highly toxic by all routes of exposure. Lethal dose in humans is 6 ppm (inhalation), 20 mg/kg (skin). Eye injury below 300 mg-min./m3. It is a blister agent, cell irritant, and systemic poison. (EPA, 1998)
Reactivity Profile
LEWISITE is hydrolyzed by alkalis. It is neutralized or inactivated as a vesicant by sodium hypochlorite [EPA, 1998].
Belongs to the Following Reactive Group(s)
Potentially Incompatible Absorbents

Use caution: Liquids with this reactive group classification have been known to react with the absorbents listed below. More info about absorbents, including situations to watch out for...

Response Recommendations

Isolation and Evacuation - Isolation and evacuation distance recommendations from the Emergency Response Guidebook (ERG).

Firefighting - Response recommendations if the chemical is on fire (or near a fire).

Non-Fire Response - Response recommendations if the chemical isn't on fire (or near a fire).

Protective Clothing - Recommendations for protective gear.

Dupont Tychem® Suit Fabrics - A table of normalized breakthrough times for DuPont Tychem suit fabrics for the chemical, if available.

First Aid - Recommended first aid treatment for people exposed to the chemical.

List of data sources.
Isolation and Evacuation
Excerpt from ERG GUIDE 153 [Substances - Toxic and/or Corrosive (Combustible)]:

As an immediate precautionary measure, isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

SPILL: If this material is being used as a weapon, see ERG Table 1 - Initial Isolation and Protective Action Distances on the UN/NA 2810 datasheet. Otherwise increase, in the downwind direction, as necessary, the isolation distance shown above.

FIRE: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2016)
(Non-Specific -- Arsenic Compound, Liquid, n.o.s.) Wear special protective clothing and positive pressure breathing apparatus.

(Non-Specific -- Arsenic Compound, Liquid, n.o.s.) Extinguish with dry chemical, carbon dioxide, water spray, or foam. Use water spray, fog, or foam for large fires. (EPA, 1998)
Non-Fire Response
Excerpt from ERG GUIDE 153 [Substances - Toxic and/or Corrosive (Combustible)]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames in immediate area). Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. DO NOT GET WATER INSIDE CONTAINERS. (ERG, 2016)
Protective Clothing
For emergency situations, wear a positive pressure, pressure-demand, full facepiece self-contained breathing apparatus (SCBA) or pressure- demand supplied air respirator with escape SCBA and a fully-encapsulating, chemical resistant suit. (EPA, 1998)
DuPont Tychem® Suit Fabrics
Tychem® Fabric Legend
QC = Tychem QC
SL = Tychem SL
TF = Tychem F
TP = Tychem ThermoPro
C3 = Tychem CPF 3
BR = Tychem BR
LV = Tychem LV
RC = Tychem Responder® CSM
TK = Tychem TK
RF = Tychem Reflector®
Testing Details
Permeation data obtained per ASTM F739. Normalized breakthrough times (the time at which the permeation rate is equal to 0.1 µg/cm2/min) reported in minutes. All liquid chemicals have been tested between approximately 20°C and 27°C unless otherwise stated. All chemicals have been tested at a concentration of greater than 95% unless otherwise stated. Chemical warfare agents (Lewisite, Sarin, Soman, Sulfur Mustard, Tabun and VX Nerve Agent) have been tested at 22°C and 50% relative humidity per military standard MIL-STD-282.
Normalized Breakthrough Times (in Minutes)
Chemical CAS Number State QC SL TF TP C3 BR LV RC TK RF
Lewisite (10 g/m²) 541-25-3 Liquid >360 120 >480 >480 >480 >480 >480
Lewisite (100 g/m²) 541-25-3 Liquid 360 360 120 120 120 >480 120
> indicates greater than.
A blank cell indicates the fabric has not been tested. The fabric may or may not offer barrier.

Special Warnings from DuPont

  1. Serged and bound seams are degraded by some hazardous liquid chemicals, such as strong acids, and should not be worn when these chemicals are present.
  2. CAUTION: This information is based upon technical data that DuPont believes to be reliable. It is subject to revision as additional knowledge and experience are gained. DuPont makes no guarantee of results and assumes no obligation or liability...
    ... in connection with this information. It is the user's responsibility to determine the level of toxicity and the proper personal protective equipment needed. The information set forth herein reflects laboratory performance of fabrics, not complete garments, under controlled conditions. It is intended for informational use by persons having technical skill for evaluation under their specific end-use conditions, at their own discretion and risk. Anyone intending to use this information should first verify that the garment selected is suitable for the intended use. In many cases, seams and closures have shorter breakthrough times and higher permeation rates than the fabric. Please contact DuPont for specific data. If fabric becomes torn, abraded or punctured, or if seams or closures fail, or if attached gloves, visors, etc. are damaged, end user should discontinue use of garment to avoid potential exposure to chemical. Since conditions of use are outside our control, we make no warranties, express or implied, including, without limitation, no warranties of merchantability or fitness for a particular use and assume no liability in connection with any use of this information. This information is not intended as a license to operate under or a recommendation to infringe any patent or technical information of DuPont or others covering any material or its use.

(DuPont, 2016)

First Aid
Warning: Lewisite vapors are extremely toxic. Inhalation of high concentrations may be fatal in as little as 10 minutes. Serious poisoning may produce symptoms within 30 to 60 minutes, but may also be delayed for a few hours. Lewisite produces an immediate searing sensation in the eye leading to permanent blindness if not decontaminated within one minute following exposure.

Signs and Symptoms of Lewisite Exposure: Signs and symptoms of acute exposure to lewisite may include headache, red staining of the conjunctiva, a garlicky odor of the breath, and pulmonary edema. Lewisite has produced an immediate and strong stinging sensation to the skin, followed by reddening within 30 minutes and blistering after 13 hours. Subnormal body temperature, restlessness, hypotension, and T-wave elevations are occasionally seen. Gastrointestinal symptoms include nausea, vomiting, diarrhea, anorexia, and abdominal pain. Generalized weakness, muscle cramping, red or green colored urine, and jaundice have also been reported.

Emergency Life-Support Procedures: Acute exposure to lewisite may require decontamination and life support for the victims. Emergency personnel should wear protective clothing appropriate to the type and degree of contamination. Air-purifying or supplied-air respiratory equipment should also be worn, as necessary. Rescue vehicles should carry supplies such as plastic sheeting and disposable plastic bags to assist in preventing spread of contamination.

Inhalation Exposure:
1. Move victims to fresh air. Emergency personnel should avoid self-exposure to lewisite.
2. Evaluate vital signs including pulse and respiratory rate and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer 100% humidified oxygen or other respiratory support.
3. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
4. Rush to a health care facility.

Dermal/Eye Exposure:
1. Remove victims from exposure. Emergency personnel should avoid self-exposure to lewisite.
2. Evaluate vital signs including pulse and respiratory rate and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer 100% humidified oxygen or other respiratory support.
3. Remove and isolate contaminated clothing as soon as possible.
4. If eye exposure has occurred, eyes must be flushed with lukewarm water for at least 15 minutes. Speed in removing material from the eyes is of extreme importance.
5. Wash exposed skin areas thoroughly with water. Speed in removing material from skin is of extreme importance.
6. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
7. Rush to a health care facility.

Ingestion Exposure:
1. Evaluate vital signs including pulse and respiratory rate and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer 100% humidified oxygen or other respiratory support.
2. DO NOT induce vomiting or attempt to neutralize.
3. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
4. Activated charcoal is of no use.
5. Rush to a health care facility. (EPA, 1998)

Physical Properties

This section contains physical properties, flammability limits, and toxic thresholds for this chemical (see definitions of each property). More property data is available for common chemicals.

See also the Levels of Concern guide for information on AEGLs, ERPGs, PACs, and IDLH values.

List of data sources.
Chemical Formula:
  • ClCHCHAsCl2
Flash Point: None (EPA, 1998)
Lower Explosive Limit (LEL): data unavailable
Upper Explosive Limit (UEL): data unavailable
Autoignition Temperature: data unavailable
Melting Point: 32 ° F (EPA, 1998)
Vapor Pressure: 0.395 mm Hg at 68.0 ° F (EPA, 1998)
Vapor Density (Relative to Air): 7.1 (EPA, 1998)
Specific Gravity: 1.888 at 68.0 ° F (EPA, 1998)
Boiling Point: 374 ° F at 760.0 mm Hg decomposes (EPA, 1998)
Molecular Weight: 207.31 (EPA, 1998)
Water Solubility: data unavailable
IDLH: data unavailable

AEGLs (Acute Exposure Guideline Levels)

Final AEGLs for Lewisite 1 (541-25-3)
Exposure Period AEGL-1 AEGL-2 AEGL-3
10 minutes NR 1.3 mg/m3 3.9 mg/m3
30 minutes NR 0.47 mg/m3 1.4 mg/m3
60 minutes NR 0.25 mg/m3 0.74 mg/m3
4 hours NR 0.07 mg/m3 0.21 mg/m3
8 hours NR 0.037 mg/m3 0.11 mg/m3
NR = Not recommended due to insufficient data
(NAC/NRC, 2016)

ERPGs (Emergency Response Planning Guidelines)

No ERPG information available.

PACs (Protective Action Criteria)

Chemical PAC-1 PAC-2 PAC-3
Chlorovinylarsine dichloride; (Lewisite 1) (541-25-3) 0.023 mg/m3 0.25 mg/m3 0.74 mg/m3
(SCAPA, 2016)

Regulatory Information

This section contains regulatory information from the U.S. Environmental Protection Agency's Title III Consolidated List of Lists and the U.S. Department of Homeland Security's Chemical Facility Anti-Terrorism Standards (see details about each regulatory field).

List of data sources.

EPA Consolidated List of Lists

Regulatory Name CAS Number/
313 Category Code
CAA 112(r)
Arsenic Compounds N020 & 313
Lewisite 541-25-3 10 pounds 10 pounds

(EPA List of Lists, 2015)

DHS Chemical Facility Anti-Terrorism Standards (CFATS)

Chemical of Interest CAS Number Min Conc STQ Security
Min Conc STQ Security
Min Conc STQ Security
Lewisite 1; [2-chlorovinyldichloroarsine] 541-25-3 CUM 100 grams CW/CWP

(DHS, 2007)

Alternate Chemical Names

This section provides a listing of alternate names for this chemical, including trade names and synonyms.