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Chemical Datasheet

ARSENIC ACID, SOLID

 6.1 - Poison

Chemical Identifiers

CAS Number UN/NA Number DOT Hazard Label USCG CHRIS Code
  • 7778-39-4
  • 1554
  • Poison
  • ASA
NIOSH Pocket Guide International Chem Safety Card
Arsenic (inorganic compounds, as As)
  • ARSENIC ACID (80% in water)
NFPA 704
data unavailable
General Description
White crystals. Excessive drying produces As2O5.5/3H2O.

Hazards

Reactivity Alerts
none
Air & Water Reactions
Hygroscopic. Water soluble.
Fire Hazard
Excerpt from 154 Polymerizable warning [Substances - Toxic and/or Corrosive (Non-Combustible)]:

Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated. For electric vehicles or equipment, 147 Polymerizable warning (lithium ion batteries) or 138 Polymerizable warning (sodium batteries) should also be consulted. (ERG, 2020)
Health Hazard
Ingestion causes irritation of stomach, weakness, other gastrointestinal symptoms. Overdose can cause arsenic poisoning, but symptoms are delayed. (USCG, 1999)
Reactivity Profile
ARSENIC ACID may evolve very toxic gaseous arsine (AsH3) from contact with active metals, such as zinc and aluminum [Inorganic Chemicals Handbook, I, p. 175]. When heated to decomposition, it produces toxic fumes of metallic arsenic [Sax, 9th ed., p. 271]. The solution is weakly acidic and a weak oxidizing agent. Reacts with alkalis to generate some heat and precipitate arsenates.
Belongs to the Following Reactive Group(s)
Potentially Incompatible Absorbents

No information available.

Response Recommendations

Isolation and Evacuation
Excerpt from 154 Polymerizable warning [Substances - Toxic and/or Corrosive (Non-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 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, 2020)
Firefighting
Excerpt from 154 Polymerizable warning [Substances - Toxic and/or Corrosive (Non-Combustible)]:

SMALL FIRE: Dry chemical, CO2 or water spray.

LARGE FIRE: Dry chemical, CO2, alcohol-resistant foam or water spray. If it can be done safely, move undamaged containers away from the area around the fire. Dike runoff from fire control for later disposal.

FIRE INVOLVING TANKS OR CAR/TRAILER LOADS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Do not get water inside containers. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks engulfed in fire. (ERG, 2020)
Non-Fire Response
Neutralizing Agents for Acids and Caustics: Flush with water, rinse with sodium bicarbonate or lime solution. (USCG, 1999)
Protective Clothing
Calamine lotion and zinc oxide powder on hands and other skin areas; rubber gloves; U. S. Bureau of Mines approved dust respirator. (USCG, 1999)
DuPont Tychem® Suit Fabrics
No information available.
First Aid
Get medical attention after all exposures to this compound. Be alert for arsenic poisoning symptoms.

SKIN: wash well with soap and water.

INGESTION: induce vomiting; drink freely lime water, milk, or raw egg; give a cathartic. (USCG, 1999)

Physical Properties

Chemical Formula:
  • AsH3O4
Flash Point: data unavailable
Lower Explosive Limit (LEL): data unavailable
Upper Explosive Limit (UEL): data unavailable
Autoignition Temperature: data unavailable
Melting Point: data unavailable
Vapor Pressure: data unavailable
Vapor Density (Relative to Air): data unavailable
Specific Gravity: 2.2 at 68°F (USCG, 1999) - Denser than water; will sink
Boiling Point: data unavailable
Molecular Weight: 229.8 (USCG, 1999)
Water Solubility: data unavailable
Ionization Energy/Potential: data unavailable
IDLH: 5 mg As/m3 ; A potential occupational carcinogen. (NIOSH, 2023)

AEGLs (Acute Exposure Guideline Levels)

No AEGL information available.

ERPGs (Emergency Response Planning Guidelines)

No ERPG information available.

PACs (Protective Action Criteria)

Chemical PAC-1 PAC-2 PAC-3
Arsenic acid; (o-Arsenic acid) Includes CASRN 1327-52-2 (7778-39-4) 2.9 mg/m3 32 mg/m3 190 mg/m3
(DOE, 2018)

Regulatory Information

EPA Consolidated List of Lists

Regulatory Name CAS Number/
313 Category Code		 EPCRA 302
EHS TPQ		 EPCRA 304
EHS RQ		 CERCLA RQ EPCRA 313
TRI		 RCRA
Code		 CAA 112(r)
RMP TQ
Arsenic Compounds N020 & 313
Arsenic acid 7778-39-4 1 pound 313c P010

(EPA List of Lists, 2022)

CISA Chemical Facility Anti-Terrorism Standards (CFATS)

No regulatory information available.

OSHA Process Safety Management (PSM) Standard List

No regulatory information available.

Alternate Chemical Names