Arsenic

1Identification

Name

Arsenic

IUPAC name

arsenic

CAS number

7440-38-2

EC number

232-066-3

Molecular formula

As

Molecular weight

74.92159 g/mol

InChIKey

RQNWIZPPADIBDY-UHFFFAOYSA-N

SMILES

[As]

PubChem CID

5359596

Synonyms

ARSENIC, Arsen, Arsenic-75, Gray arsenic, Colloidal arsenic, Arsenic, elemental, Scherbenkobalt, Dietary Arsenic, Arsenic 75, RefChem:5564, ELEMENTAL ARSENIC, ARSENICUM METALLICUM, Arsenic Black, Arsenic ion

Recommended uses

• Inorganic arsenic is primarily used as a preservative to make wood resistant to rot and decay, although the use for certain residential items, such as decks and picnic tables, has been phased out. Inorganic arsenic is still used for this purpose in industrial applications. Arsenic and its compounds have been used as alloy additives; in electronic devices, such as smartphones; in veterinary medicines; in pigment production; in glass manufacturing; as bronzing or decolorizing agents; in textile printing; in tanning; and other uses. Until the 1940s, inorganic arsenic was used as a therapeutic agent in the treatment of various diseases, such as leukemia, psoriasis, and chronic bronchial asthma.
  EPA Hazardous Air Pollutants
• MINING OR SMELTING: Smelt lead, copper, zinc, cobalt, nickel, or gold; Harden copper and lead; MANUFACTURING: Pesticides (sheep dips, insecticides, herbicides, fungicides, algicides, wood preservatives, cotton desiccants); Lead-arsenic alloys for solder, battery grids, or cable shielding; Electronics (microwave devices, lasers, light-emitting diodes, photoelectric cells, semiconductors); Clarified glass or ceramics; Pigments; USING OR DISPOSING: Clean fossil fuel furnaces, flues, or boilers; Sand or burn arsenic-treated wood; Lead arsenate, calcium arsenate, and sodium arsenite have been used as pesticides;
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• EPA regulates copper smelters, glass manufacturing emissions, and drinking water. Inorganic arsenic no longer used in agriculture in the U.S. [ATSDR ToxFAQs] Arsenic-treated lumber for residential use voluntarily banned in 2003; [Olson, p. 140]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• Other Alloys Fuel agents Flux agent Hardener Intermediate
  EPA Chemical Data Reporting (CDR)
• Other Not Known or Reasonably Ascertainable Flux agent Hardener
  EPA Chemical Data Reporting (CDR)

Use categories: Chemical Classes -> Inorganic substances · Food Contaminant -> METALS -> JECFA Functional Classes

Description

• Arsenic is a naturally occurring element widely distributed in the earth's crust. In the environment, arsenic is combined with oxygen, chlorine, and sulfur to form inorganic arsenic compounds. Arsenic in animals and plants combines with carbon and hydrogen to form organic arsenic compounds. Inorganic arsenic compounds are mainly used to preserve wood. Copper chromated arsenic (CCA) is used to make "pressure-treated" lumber. CCA is no longer used in the U.S. for residential uses; it is still used in industrial applications. Organic arsenic compounds are used as pesticides, primarily on cotton plants.
  Agency for Toxic Substances and Disease Registry (ATSDR)
• Arsenic (inorganic arsenic compounds) can cause cancer according to California Labor Code.
  California Office of Environmental Health Hazard Assessment (OEHHA)
• Arsenic appears as a grayish metallic solid that turns black upon exposure to air. Insoluble in water. Toxic by ingestion.
  CAMEO Chemicals

2Hazard identification

Signal word

Danger

Pictograms

GHS06, GHS09

Classification source

Regulation (EC) No 1272/2008 of the European Parliament and of the Council

Precautionary statements

Other reported classifications

6 classification records exist across sources. Differences usually reflect purity, physical form or impurities.

Health hazards

• Poisonous by inhalation of dust or by ingestion. Regardless of exposure route, symptoms in most cases are characteristic of severe gastritis or gastroenteritis. All chemical forms of arsenic eventually produce similar toxic effects. Symptoms may be delayed. (USCG, 1999)
  CAMEO Chemicals
• · Highly toxic, may be fatal if inhaled, ingested or absorbed through skin. · Contact with molten substance may cause severe burns to skin and eyes. · Avoid any skin contact. · Fire may produce irritating, corrosive and/or toxic gases. · Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental contamination.
  Emergency Response Guidebook (ERG)

Fire hazards

• Special Hazards of Combustion Products: Contain highly toxic arsenic trioxide and other forms of arsenic. Arsenic gas, the most dangerous form of arsenic, is produced upon contact with an acid or acid fumes. Behavior in Fire: Burns to produce dense white fumes of highly toxic arsenic trioxide. (USCG, 1999)
  CAMEO Chemicals
• · Combustible material: may burn but does not ignite readily. · Containers may explode when heated. · Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. · Runoff may pollute waterways. · Substance may be transported in a molten form.
  Emergency Response Guidebook (ERG)
• Combustible. Gives off irritating or toxic fumes (or gases) in a fire. Risk of fire and explosion on contact with incompatible substances. See Chemical Dangers.
  ILO-WHO International Chemical Safety Cards (ICSCs)

Hazards summary

• Arsenic is a naturally occurring element widely distributed in the earth's crust. In the environment, arsenic is combined with oxygen, chlorine, and sulfur to form inorganic arsenic compounds. Arsenic in animals and plants combines with carbon and hydrogen to form organic arsenic compounds. Inorganic arsenic compounds are mainly used to preserve wood. Copper chromated arsenic (CCA) is used to make "pressure-treated" lumber. CCA is no longer used in the U.S. for residential uses; it is still used in industrial applications. Organic arsenic compounds are used as pesticides, primarily on cotton plants.
  Agency for Toxic Substances and Disease Registry (ATSDR)
• Arsenic, a naturally occurring element, is found throughout the environment. For most people, exposure to arsenic, including to inorganic arsenic compounds, occurs through their diet. Acute (short-term), high-level inhalation exposure to inorganic arsenic has resulted in respiratory effects (cough, dyspnea, chest pain), gastrointestinal effects (nausea, diarrhea, abdominal pain), and central and peripheral nervous system effects. Chronic (long-term) inhalation exposure to inorganic arsenic in humans is associated with skin, cardiovascular, and neurological effects.
  EPA Hazardous Air Pollutants

3Composition / information on ingredients

This page describes the pure substance. Commercial products may be solutions or mixtures. Check Section 3 of your supplier's SDS for concentrations and other ingredients.

4First-aid measures

• Excerpt from NIOSH Pocket Guide for Arsenic (inorganic compounds, as As): Eye: IRRIGATE IMMEDIATELY - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately. Skin: SOAP WASH IMMEDIATELY - If this chemical contacts the skin, immediately wash the contaminated skin with soap and water. If this chemical penetrates the clothing, immediately remove the clothing, wash the skin with soap and water, and get medical attention promptly. Breathing: RESPIRATORY SUPPORT - If a person breathes large amounts of this chemical, move the exposed person to fresh air at once.
  CAMEO Chemicals
• General First Aid: · Call 911 or emergency medical service. · Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination. · Move victim to fresh air if it can be done safely. · Administer oxygen if breathing is difficult. · If victim is not breathing: -- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance. -- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped with a one-way valve or other device).
  Emergency Response Guidebook (ERG)
• (General first aid procedures) Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately. Skin: Soap wash immediately - If this chemical contacts the skin, immediately wash the contaminated skin with soap and water. If this chemical penetrates the clothing, immediately remove the clothing, wash the skin with soap and water, and get medical attention promptly. Breathing: Respiratory support Swallow: Medical attention immediately - If this chemical has been swallowed, get medical attention immediately.
  The National Institute for Occupational Safety and Health (NIOSH)

Symptoms of exposure

• See Ingestion.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Abdominal pain. Diarrhoea. Nausea. Vomiting. Weakness. Shock or collapse. Unconsciousness.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Ulceration of nasal septum, dermatitis, gastrointestinal disturbances, peripheral neuropathy, resp irritation, hyperpigmentation of skin, [potential occupational carcinogen]
  The National Institute for Occupational Safety and Health (NIOSH)

5Fire-fighting measures

• If material involved in fire: Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty.) Use water in flooding quantities as fog. Use foam, dry chemical, or carbon dioxide. /Arsenical cmpd, liquid, NOS/
  Hazardous Substances Data Bank (HSDB)
• Personnel protection: ... Wear positive pressure self-contained breathing apparatus when fighting fires involving this material. /Arsenical cmpd, solid, NOS/
  Hazardous Substances Data Bank (HSDB)

Hazardous combustion products

• Fire may produce poisonous or irritating gases.
  Hazardous Substances Data Bank (HSDB)

6Accidental release measures

Isolation and evacuation

• Excerpt from ERG Guide 152 [Substances - Toxic (Combustible)]: 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: Increase the immediate precautionary measure distance, in the downwind direction, as necessary. FIRE: If tank, rail tank car or highway tank 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, 2024)
  CAMEO Chemicals
• 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 · For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances. · For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind direction, as necessary. Fire · If tank, rail tank car or highway tank 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.
  Emergency Response Guidebook (ERG)

Spill cleanup

• Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Do NOT let this chemical enter the environment. Sweep spilled substance into sealable containers. Carefully collect remainder. Then store and dispose of according to local regulations.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Solvent extraction with high molecular weight amines and quaternary ammonium compounds may be a promising technique for the removal of toxic elements like ... arsenic ... from industrial effluents.
  Hazardous Substances Data Bank (HSDB)
• Prompt cleanup and removal are necessary. Control runoff and isolate discharged material for proper disposal.
  Hazardous Substances Data Bank (HSDB)

7Handling and storage

• Separated from strong oxidants, acids, halogens and food and feedstuffs. Well closed. Provision to contain effluent from fire extinguishing. Store in an area without drain or sewer access.
  ILO-WHO International Chemical Safety Cards (ICSCs)

8Exposure controls / personal protection

Personal protective equipment

• Excerpt from NIOSH Pocket Guide for Arsenic (inorganic compounds, as As): Skin: PREVENT SKIN CONTACT - Wear appropriate personal protective clothing to prevent skin contact. Eyes: PREVENT EYE CONTACT - Wear appropriate eye protection to prevent eye contact. Wash skin: • WHEN CONTAMINATED - The worker should immediately wash the skin when it becomes contaminated. • DAILY - The worker should wash daily at the end of each work shift, and prior to eating, drinking, smoking, etc. Remove: WHEN WET OR CONTAMINATED - Work clothing that becomes wet or significantly contaminated should be removed and replaced.
  CAMEO Chemicals
• Wear appropriate personal protective clothing to prevent skin contact.
  Hazardous Substances Data Bank (HSDB)
• Wear appropriate eye protection to prevent eye contact.
  Hazardous Substances Data Bank (HSDB)
• Eyewash fountains should be provided in areas where there is any possibility that workers could be exposed to the substance; this is irrespective of the recommendation involving the wearing of eye protection.
  Hazardous Substances Data Bank (HSDB)

Respirator recommendations

• (See OSHA respirator requirements for selected chemicals) NIOSH At concentrations above the NIOSH REL, or where there is no REL, at any detectable concentration: (APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode (APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus Escape: (APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted acid gas canister having an N100, R100, or P100…
  The National Institute for Occupational Safety and Health (NIOSH)

9Physical and chemical properties

10Stability and reactivity

Reactivity

• ARSENIC reacts incandescently with bromine trifluoride, even at 10 °C [Mellor 2:113 1946-47]. Causes bromoazide to explode upon contact. Ignites if ground up together with solid potassium permanganate [Mellor 12:322 1946-47]. Is oxidized by sodium peroxide with incandescence [Mellor 2:490-93 1946-47]. A combination of finely divided arsenic with finely divided bromates (also chlorates and iodates) of barium, calcium, magnesium, potassium, sodium, or zinc can explode by heat, percussion, and friction [Mellor 2:310 1946-47]. Bromine pentafluoride reacts readily in the cold with arsenic. Ignition usually occurs. Reacts vigorously with fluorine at ordinary temperatures [Mellor 9:34 1946-47].
  CAMEO Chemicals
• Turns black on exposure to air. Insoluble in water.
  CAMEO Chemicals

Incompatible materials and hazardous reactions

• Arsine is formed when any inorganic arsenic bearing material is brought in contact with zinc and sulfuric acid.
  Hazardous Substances Data Bank (HSDB)
• Arsine may be accidentally formed by the reaction of arsenic impurities in commercial acids stored in metal tanks. ...
  Hazardous Substances Data Bank (HSDB)
• ... The /bromine azide/ liquid explodes on contact with arsenic. ...
  Hazardous Substances Data Bank (HSDB)

Chemical stability

• LOSES ITS LUSTER ON EXPOSURE TO AIR, FORMING A BLACK MODIFICATION + AS2O3
  Hazardous Substances Data Bank (HSDB)

11Toxicological information

Target organs

• Cancer, Cardiovascular (Heart and Blood Vessels), Dermal (Skin), Endocrine (Glands and Hormones), Gastrointestinal (Digestive), Hematological (Blood Forming), Neurological (Nervous System), Renal (Urinary System or Kidneys), Respiratory (From the Nose to the Lungs)
  Agency for Toxic Substances and Disease Registry (ATSDR)
• Cardiovascular Endocrine
  EPA Integrated Risk Information System (IRIS)

Short-term exposure effects

• The substance may cause effects on the gastrointestinal tract. This may result in severe gastroenteritis, loss of fluids and electrolytes, cardiac disorders, shock and convulsions. Exposure far above the OEL could cause death. The effects may be delayed. Medical observation is indicated.
  ILO-WHO International Chemical Safety Cards (ICSCs)

Long-term exposure effects

• The substance may have effects on the skin, mucous membranes, peripheral nervous system, liver and bone marrow. This may result in pigmentation disorders, hyperkeratosis, perforation of the nasal septum, neuropathy, anaemia and liver impairment. This substance is carcinogenic to humans. Animal tests show that this substance possibly causes toxicity to human reproduction or development.
  ILO-WHO International Chemical Safety Cards (ICSCs)

12Ecological information

Not available in the public sources we compile. Check Section 12 of the supplier's SDS.

13Disposal considerations

• SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.
  Hazardous Substances Data Bank (HSDB)
• Arsenic elemental arsenic wastes should be placed in long term storage or returned to suppliers or manufacturers for reprocessing.
  Hazardous Substances Data Bank (HSDB)
• Arsenic bearing sludges from the purification process in the production of antimony oxide are poor candidates for incineration.
  Hazardous Substances Data Bank (HSDB)

14Transport information

UN number: UN 1558

Shipping name

• UN 1558; Arsenic
  Hazardous Substances Data Bank (HSDB)
• IMO 6.1; Arsenic
  Hazardous Substances Data Bank (HSDB)

DOT hazard class

• Arsenic
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172
• UN1558
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172
• Div 6.1 Poisonous materials (49 eCFR § 173.132)
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172

DOT label

• Poison
  CAMEO Chemicals

UN classification

• UN Hazard Class: 6.1; UN Pack Group: II
  ILO-WHO International Chemical Safety Cards (ICSCs)

Emergency Response Guidebook

• 1558 152
  Emergency Response Guidebook (ERG)
• 1558 152(metal)
  The National Institute for Occupational Safety and Health (NIOSH)

How DOT hazard classes work →

15Regulatory information

• Inorganic arsenic has been designated as a hazardous air pollutant under section 112 of the Clean Air Act. /Inorganic Arsenic/
  Hazardous Substances Data Bank (HSDB)
• Tolerances for total residues of combined arsenic (calculated as As) in food are established as follows: (a) In edible tissues & in eggs of chickens & turkeys: 0.5 ppm in uncooked muscle tissue; 2 ppm in uncooked edible by-products; & 0.5 ppm in eggs. (b) In edible tissues of swine: 2 ppm in uncooked liver & kidney; 0.5 ppm in uncooked muscle tissue & by-products other than liver & kidney. /Arsenic/
  Hazardous Substances Data Bank (HSDB)
• If material involved in fire: Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty.) Use water in flooding quantities as fog. Use foam, dry chemical, or carbon dioxide. /Arsenical cmpd, solid, NOS/
  Hazardous Substances Data Bank (HSDB)
• For the maximum protection of human health from the potential carcinogenic effects due to exposure of arsenic through ingestion of contaminated water & contaminated aquatic organisms, the ambient water concn should be zero based on the nonthreshold assumption for this chemical. However, zero level may not be attainable at the present time. Therefore, the levels which may result in incremental increase of cancer risk over the lifetime are estimated at 1X10-5, 1X10-6, & 1X10-7. The corresponding criteria are 22 ng/l, 2.2 ng/l, & .22 ng/l, respectively .... For consumption of aquatic organisms only, excluding consumption of water, the levels are 175 ng/ml, 17.5 ng/l, & 1.75 ng/l, respectively.
  Hazardous Substances Data Bank (HSDB)
• Toxic pollutant designated pursuant to section 307(a)(1) of the Federal Water Pollution Control Act and is subject to effluent limitations. /Arsenic & cmpd/
  Hazardous Substances Data Bank (HSDB)
• Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 1 lb or 0.454 kg. The toll free number of the NRC is (800) 424-8802; In the Washington D.C. metropolitan area (202) 426-2675. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b). No reporting of releases of this hazardous substance is required if the diameter of the pieces of the solid metal released is equal to or exceedes 100 micrometers (0.004 inches).
  Hazardous Substances Data Bank (HSDB)
• D004; A solid waste containing arsenic may or may not become characterized as a hazardous waste when subjected to the Toxicity Characteristic Leaching Procedure listed in 40 CFR 261.24, and if so characterized, must be managed as a hazardous waste.
  Hazardous Substances Data Bank (HSDB)
• Tolerances for total residues of combined arsenic (calculated as As) in food are established as follows: (a) In edible tissues & in eggs of chickens & turkeys: 0.5 ppm in uncooked muscle tissue; 2 ppm in uncooked edible by-products; & 0.5 ppm in eggs. (b) In edible tissues of swine: 2 ppm in uncooked liver & kidney; 0.5 ppm in uncooked muscle tissue & by-products other than liver & kidney. /Arsenic/
  Hazardous Substances Data Bank (HSDB)

Overview of SDS regulations (OSHA HazCom, WHMIS, REACH/CLP) →

16Other information

Compiled from PubChem CID 5359596 and the sources it aggregates (attributed inline). Data retrieved 2026-10-12. This summary describes the pure substance and is not a supplier SDS.