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PHOSGENE OXIME (CX) : Blister Agent

CAS #: 1794-86-1

RTECS #: Not established/determined

UN #: 2811 (Guide 154)

Common Names:

  • Dichloroformoxime
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Agent Characteristics

  • APPEARANCE: Colorless, crystalline solid or yellowish-brown liquid.
  • DESCRIPTION: Phosgene oxime is an urticant (nettle agent). On contact with the skin, it causes redness (erythema) and hives (wheals and urticaria). Phosgene oxime does not produce blistering (vesication). Very little is known about the effects of phosgene oxime on humans; its mechanism of action is unknown. The effects of phosgene oxime vapor and liquid on the skin, eyes and lungs are almost instantaneous. No other chemical agent is capable of producing immediate extreme pain followed by rapid local tissue death (necrosis). Phosgene oxime was developed as a potential chemical warfare agent (military designation CX), but has not been used on the battlefield. Phosgene oxime is of military interest because it penetrates garments and rubber much more quickly than do other chemical agents. When mixed with other chemical agents (e.g., nerve agents), the rapid skin damage caused by phosgene oxime may make the skin more permeable to the second agent. It has a disagreeable, penetrating odor and a violently irritating vapor. The solid can release enough vapor to cause symptoms.
  • METHODS OF DISSEMINATION:
    • Indoor Air: Phosgene oxime can be released into indoor air as a vapor.
    • Water: Phosgene oxime can contaminate water.
    • Food: Phosgene oxime can contaminate food.
    • Outdoor Air: Phosgene oxime can be released into outdoor air as a vapor.
    • Agricultural: If phosgene oxime is released into the air as a vapor, it is highly unlikely to contaminate agricultural products.
  • ROUTES OF EXPOSURE: Phosgene oxime can be absorbed into the body by inhalation, ingestion, skin contact, or eye contact. Ingestion is an uncommon route of exposure.
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Personal Protective Equipment

  • GENERAL INFORMATION: First Responders should use a NIOSH-certified Chemical, Biological, Radiological, Nuclear (CBRN) Self Contained Breathing Apparatus (SCBA) with a Level A protective suit when entering an area with an unknown contaminant or when entering an area where the concentration of the contaminant is unknown. Level A protection should be used until monitoring results confirm the contaminant and the concentration of the contaminant.
    NOTE: Safe use of protective clothing and equipment requires specific skills developed through training and experience.
  • LEVEL A: (RED ZONE): Select when the greatest level of skin, respiratory, and eye protection is required. This is the maximum protection for workers in danger of exposure to unknown chemical hazards or levels above the IDLH or greater than the AEGL-2.
    • A NIOSH-certified CBRN full-face-piece SCBA operated in a pressure-demand mode or a pressure-demand supplied air hose respirator with an auxiliary escape bottle.
    • A Totally-Encapsulating Chemical Protective (TECP) suit that provides protection against CBRN agents.
    • Chemical-resistant gloves (outer).
    • Chemical-resistant gloves (inner).
    • Chemical-resistant boots with a steel toe and shank.
    • Coveralls, long underwear, and a hard hat worn under the TECP suit are optional items.
  • LEVEL B: (RED ZONE): Select when the highest level of respiratory protection is necessary but a lesser level of skin protection is required. This is the minimum protection for workers in danger of exposure to unknown chemical hazards or levels above the IDLH or greater than AEGL-2. It differs from Level A in that it incorporates a non-encapsulating, splash-protective, chemical-resistant splash suit that provides Level A protection against liquids but is not airtight.
    • A NIOSH-certified CBRN full-face-piece SCBA operated in a pressure-demand mode or a pressure-demand supplied air hose respirator with an auxiliary escape bottle.
    • A hooded chemical-resistant suit that provides protection against CBRN agents.
    • Chemical-resistant gloves (outer).
    • Chemical-resistant gloves (inner).
    • Chemical-resistant boots with a steel toe and shank.
    • Coveralls, long underwear, a hard hat worn under the chemical-resistant suit, and chemical-resistant disposable boot-covers worn over the chemical-resistant suit are optional items.
  • LEVEL C: (YELLOW ZONE): Select when the contaminant and concentration of the contaminant are known and the respiratory protection criteria factors for using Air Purifying Respirators (APR) or Powered Air Purifying Respirators (PAPR) are met. This level is appropriate when decontaminating patient/victims.
    • A NIOSH-certified CBRN tight-fitting APR with a canister-type gas mask or CBRN PAPR for air levels greater than AEGL-2.
    • A NIOSH-certified CBRN PAPR with a loose-fitting face-piece, hood, or helmet and a filter or a combination organic vapor, acid gas, and particulate cartridge/filter combination or a continuous flow respirator for air levels greater than AEGL-1.
    • A hooded chemical-resistant suit that provides protection against CBRN agents.
    • Chemical-resistant gloves (outer).
    • Chemical-resistant gloves (inner).
    • Chemical-resistant boots with a steel toe and shank.
    • Escape mask, face shield, coveralls, long underwear, a hard hat worn under the chemical-resistant suit, and chemical-resistant disposable boot-covers worn over the chemical-resistant suit are optional items.
  • LEVEL D: (GREEN ZONE): Select when the contaminant and concentration of the contaminant are known and the concentration is below the appropriate occupational exposure limit or less than AEGL-1 for the stated duration times.
    • Limited to coveralls or other work clothes, boots, and gloves.
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Emergency Response

  • CHEMICAL DANGERS:
    • Phosgene oxime decomposes when in contact with many metals.
    • Phosgene oxime is corrosive to most metals.
    • Contact with metals may evolve flammable hydrogen gas.
  • EXPLOSION HAZARDS:
    • Containers may explode when heated.
  • FIRE FIGHTING INFORMATION:
    • Phosgene oxime is non-combustible.
    • The agent itself does not burn, but may decompose upon heating to produce corrosive and/or toxic fumes.
    • Fire may produce irritating, corrosive, and/or toxic gases.
    • The agent may be an oxidizer, and it may ignite combustibles (e.g., wood, paper, oil, or clothing).
    • For small fires, use dry chemical, carbon dioxide, or water spray.
    • For large fires, use dry chemical, carbon dioxide, alcohol-resistant foam, or water spray. Move containers from the fire area if it is possible to do so without risk to personnel. Dike fire control water for later disposal; do not scatter the material.
    • For fire involving tanks or car/trailer loads, fight the fire from maximum distance or use unmanned hose holders 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 tanks. Always stay away from tanks engulfed in fire.
    • Run-off from fire control or dilution water may be corrosive and/or toxic, and it may cause pollution.
    • If the situation allows, control and properly dispose of run-off (effluent).
  • INITIAL ISOLATION AND PROTECTIVE ACTION DISTANCES:
    • If a tank, rail car, or tank truck is involved in a fire, isolate it for 0.5 mi (800 m) in all directions; also, consider initial evacuation for 0.5 mi (800 m) in all directions.
    • Small spills (involving the release of approximately 52.83 gallons (200 liters) or less), when phosgene oxime (CX) is used as a weapon
    • First, isolate in all directions 100 ft (30 m).
    • Then protect persons downwind during the day 0.1 mi (0.2 km).
    • Then protect persons downwind during the night 0.3 mi (0.5 km).
    • Large spills (involving quantities greater than 52.83 gallons (200 liters)), when phosgene xime (CX) is used as a weapon
    • First, isolate in all directions 300 ft (90 m).
    • Then protect persons downwind during the day 0.6 mi (1.0 km).
    • Then protect persons downwind during the night 1.9 mi (3.1 km).
  • PHYSICAL DANGERS:
    • Vapors are heavier than air. They will spread along the ground and collect and stay in poorly-ventilated, low-lying, or confined areas (e.g., sewers, basements, and tanks).
    • Hazardous concentrations may develop quickly in enclosed, poorly-ventilated, or low-lying areas. Keep out of these areas. Stay upwind.
  • NFPA 704 Signal:
    • Health: Not established/determined
    • Flammability: Not established/determined
    • Reactivity: Not established/determined
    • Special: Not established/determined
  • SAMPLING AND ANALYSIS:
    • OSHA: Not established/determined
    • NIOSH: Not established/determined
  • ADDITIONAL SAMPLING AND ANALYSIS INFORMATION:
    References are provided for the convenience of the reader and do not imply endorsement by NIOSH.

    • AIR MATRIX
      No references were identified for this sampling matrix for this agent.


    • OTHER
      No references were identified for this sampling matrix for this agent.


    • SOIL MATRIX
      No references were identified for this sampling matrix for this agent.


    • SURFACES
      No references were identified for this sampling matrix for this agent.


    • WATER
      Laniewski K, Borén H, Grimvall A, Ekelund M [1998]. Pyrolysis–gas chromatography of chloroorganic compounds in precipitation. J Chromatogr A 826(2):201-210.

      Steiner WE, Clowers BH, Matz LM, Siems WF, Hill HH, Jr. [2002]. Rapid screening of aqueous chemical warfare agent degradation products: ambient pressure ion mobility mass spectrometry. Anal.Chem 74(17):4343-4352.

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Signs/Symptoms

  • TIME COURSE: Exposure to phosgene oxime produces almost instantaneous adverse health effects. This agent causes almost unbearable pain to unprotected skin and eyes and immediate irritation to the respiratory tract when inhaled. Within 30 minutes after skin contact with liquid or solid phosgene oxime, hives (urticaria) form, followed by tissue death (necrosis). Extreme pain may persist for days, and healing may require months.
  • EFFECTS OF SHORT-TERM (LESS THAN 8-HOURS) EXPOSURE: Phosgene oxime causes more severe tissue damage than do other blister agents (vesicants) and nettle agents (urticants). It has been called a corrosive agent. Skin lesions caused by phosgene oxime are similar to those caused by a strong acid. Eye, skin, or inhalation exposure may result in whole-body (systemic) toxicity, including the accumulation of fluid in the lungs (pulmonary edema).
  • EYE EXPOSURE:
    • Immediate pain, inflammation of the membranes (conjunctivitis), corrosion of the cornea (keratitis), excessive tear production (lacrimation), vision loss, and temporary blindness.
    • Eye lesions are similar to those caused by exposure to lewisite.
  • INGESTION EXPOSURE:
    • Probable hemorrhagic inflammatory lesions and destruction of the lining of the gastrointestinal (GI) tract.
  • INHALATION EXPOSURE:
    • Immediate and incapacitating irritation, pain, and local tissue destruction of the upper airways; difficulty breathing or shortness of breath (dyspnea); and cough.
    • The main airway lesion caused by exposure to phosgene oxime is the accumulation of fluid in the lungs (pulmonary edema), which may occur following inhalation exposure or after whole-body (systemic) absorption of the agent. Pulmonary edema may be accompanied by destruction of tissue and irritation of the airways (necrotizing bronchiolitis) and by blood clots in the lungs (pulmonary thrombosis).
  • SKIN EXPOSURE:
    • Immediate pain, whitening (blanching) of the skin surrounded by a red (erythematous) ring, local tissue death (necrosis), itching (pruritus), and hives (urticaria).
    • Phosgene oxime is absorbed within seconds through the skin.
    • Severe skin exposures may produce the accumulation of fluid in the lungs (pulmonary edema) due to blood clots in the lungs (pulmonary thrombosis) several hours after exposure.
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Decontamination

  • INTRODUCTION: The purpose of decontamination is to make an individual and/or their equipment safe by physically removing toxic substances quickly and effectively. Care should be taken during decontamination, because absorbed agent can be released from clothing and skin as a gas. Your Incident Commander will provide you with decontaminants specific for the agent released or the agent believed to have been released.
  • DECONTAMINATION CORRIDOR: The following are recommendations to protect the first responders from the release area:
    • Position the decontamination corridor upwind and uphill of the hot zone.
    • The warm zone should include two decontamination corridors. One decontamination corridor is used to enter the warm zone and the other for exiting the warm zone into the cold zone. The decontamination zone for exiting should be upwind and uphill from the zone used to enter.
    • Decontamination area workers should wear appropriate PPE. See the PPE section of this card for detailed information.
    • A solution of detergent and water (which should have a pH value of at least 8 but should not exceed a pH value of 10.5) should be available for use in decontamination procedures. Soft brushes should be available to remove contamination from the PPE.
    • Labeled, durable 6-mil polyethylene bags should be available for disposal of contaminated PPE.
  • INDIVIDUAL DECONTAMINATION: The following methods can be used to decontaminate an individual:
    • Decontamination of First Responder:
      • Begin washing PPE of the first responder using soap and water solution and a soft brush. Always move in a downward motion (from head to toe). Make sure to get into all areas, especially folds in the clothing. Wash and rinse (using cold or warm water) until the contaminant is thoroughly removed.
      • Remove PPE by rolling downward (from head to toe) and avoid pulling PPE off over the head. Remove the SCBA after other PPE has been removed.
      • Place all PPE in labeled durable 6-mil polyethylene bags.
    • Decontamination of Patient/Victim:
      • Remove the patient/victim from the contaminated area and into the decontamination corridor.
      • Remove all clothing (at least down to their undergarments) and place the clothing in a labeled durable 6-mil polyethylene bag.
      • Thoroughly wash and rinse (using cold or warm water) the contaminated skin of the patient/victim using a soap and water solution. Be careful not to break the patient/victim’s skin during the decontamination process, and cover all open wounds.
      • Cover the patient/victim to prevent shock and loss of body heat.
      • Move the patient/victim to an area where emergency medical treatment can be provided.
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First Aid

  • GENERAL INFORMATION: There is no recommended therapeutic regimen for phosgene oxime. Treatment is primarily supportive. Decontamination immediately after skin and eye exposure is the only means for preventing or decreasing tissue damage since phosgene oxime is absorbed within seconds.
  • ANTIDOTE: There is no antidote for phosgene oxime toxicity.
  • EYE:
    • Immediately remove the patient/victim from the source of exposure.
    • Immediately wash eyes with large amounts of tepid water for at least 15 minutes.
    • Eyes must be decontaminated within minutes after exposure to limit injury.
    • Do not cover eyes with bandages.
    • Seek medical attention immediately.
  • INGESTION:
    • Immediately remove the patient/victim from the source of exposure.
    • Ensure that the patient/victim has an unobstructed airway.
    • Do not induce vomiting (emesis).
    • Administer nothing by mouth (NPO).
    • Seek medical attention immediately.
  • INHALATION:
    • Immediately remove the patient/victim from the source of exposure.
    • Evaluate respiratory function and pulse.
    • Ensure that the patient/victim has an unobstructed airway.
    • If shortness of breath occurs or breathing is difficult (dyspnea), administer oxygen.
    • Assist ventilation as required. Always use a barrier or bag-valve-mask device.
    • If breathing has ceased (apnea), provide artificial respiration.
    • Monitor for and treat spasmodic narrowing of the large airways (bronchospasm), if it occurs.
    • Seek medical attention immediately.
  • SKIN:
    • Immediately remove the patient/victim from the source of exposure.
    • See the decontamination section for patient/victim decontamination procedures.
    • Skin must be decontaminated within minutes after exposure to limit injury.
    • Seek medical attention immediately.
See ATSDR Medical Management Guidelines for Phosgene Oxime for more detailed recommendations, https://www.atsdr.cdc.gov/MHMI/mmg167.pdf
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Long-Term Implications

  • MEDICAL TREATMENT: Extreme pain may persist for days. Patients/victims should be observed for signs of whole-body (systemic) toxicity, including accumulation of fluid in the lungs (pulmonary edema). Gastric lavage is contraindicated following ingestion of this agent due to the risk of perforation of the esophagus or upper airway.
  • DELAYED EFFECTS OF EXPOSURE: Information is unavailable about the long term effects of exposure to phosgene oxime.
  • EFFECTS OF CHRONIC OR REPEATED EXPOSURE: Information is unavailable about the carcinogenicity, developmental toxicity, or reproductive toxicity from chronic or repeated exposure to phosgene oxime.
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On-Site Fatalities

  • INCIDENT SITE:
    • Consult with the Incident Commander regarding the agent dispersed, dissemination method, level of PPE required, location, geographic complications (if any), and the approximate number of remains.
    • Coordinate responsibilities and prepare to enter the scene as part of the evaluation team along with the FBI HazMat Technician, local law enforcement evidence technician, and other relevant personnel.
    • Begin tracking remains using waterproof tags.
  • RECOVERY AND ON-SITE MORGUE:
    • Wear PPE until all remains are deemed free of contamination.
    • Establish a preliminary (holding) morgue.
    • Gather evidence, and place it in a clearly labeled impervious container. Hand any evidence over to the FBI.
    • Remove and tag personal effects.
    • Perform a thorough external evaluation and a preliminary identification check.
    • See the Decontamination section for decontamination procedures.
    • Decontaminate remains before they are removed from the incident site.
See Guidelines for Mass Fatality Management During Terrorist Incidents Involving Chemical Agents, U.S. Army Soldier and Biological Chemical Command (SBCCOM), November, 2001 for detailed recommendations.
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Occupational Exposure Limits

  • NIOSH REL:
    • Not established/determined
  • OSHA PEL:
    • Not established/determined
  • ACGIH TLV:
    • Not established/determined
  • NIOSH IDLH: Not established/determined
  • DOE TEEL:
    • TEEL-0: Not established/determined
    • TEEL-1: Not established/determined
    • TEEL-2: Not established/determined
    • TEEL-3: Not established/determined
  • AIHA ERPG:
    • ERPG-1: Not established/determined
    • ERPG-2: Not established/determined
    • ERPG-3: Not established/determined
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Acute Exposure Guidelines [Interim]

10 min 30 min 60 min 4 hr 8 hr
AEGL 1
(discomfort, non-disabling) - mg/m3		 0.17 mg/m3 0.056 mg/m3 0.028 mg/m3 0.0069 mg/m3 0.0035 mg/m3
AEGL 2
(irreversible or other serious, long-lasting effects or impaired ability to escape) - mg/m3		 0.50 mg/m3 0.17 mg/m3 0.083 mg/m3 0.021 mg/m3 0.010 mg/m3
AEGL 3
(life-threatening effects or death) - mg/m3		 36 mg/m3 25 mg/m3 13 mg/m3 3.1 mg/m3 1.6 mg/m3

NOTE THAT VALUES ARE IN mg/m3, NOT ppm.

Technical Support Document

IMPORTANT NOTE: Interim AEGLs are established following review and consideration by the National Advisory Committee for AEGLs (NAC/AEGL) of public comments on Proposed AEGLs. Interim AEGLs are available for use by organizations while awaiting NRC/NAS peer review and publication of Final AEGLs. Changes to Interim values and Technical Support Documents may occur prior to publication of Final AEGL values. In some cases, revised Interim values may be posted on this Web site, but the revised Interim Technical Support Document for the chemical may be subject to change. (Further information is available through AEGL Process).

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Decontamination (Environment and Equipment)

  • ENVIRONMENT/SPILLAGE DISPOSAL: The following methods can be used to decontaminate the environment/spillage disposal:
    • Do not touch or walk through the spilled agent if at all possible. However, if you must, personnel should wear the appropriate PPE during environmental decontamination. See the PPE section of this card for detailed information.
    • Keep combustibles (e.g., wood, paper, and oil) away from the spilled agent.
    • Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact the spilled agent.
    • Do not direct water at the spill or the source of the leak.
    • Stop the leak if it is possible to do so without risk to personnel.
    • Prevent entry into waterways, sewers, basements, or confined areas.
    • Isolate the area until gas has dispersed.
    • Ventilate the area.
  • EQUIPMENT: Agents can seep into the crevices of equipment making it dangerous to handle. The following methods can be used to decontaminate equipment:
    • Not established/determined
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Agent Properties

  • Chemical Formula:
    CHCl2NO
  • Aqueous solubility:
    Soluble
  • Boiling Point:
    262°F (128°C)
  • Density:
    Liquid: Not available
    Vapor: < 3.9 (air = 1.0)
  • Flammability:
    Not combustible
  • Flashpoint:
    Not established/determined
  • Ionization potential:
    Not established/determined
  • Log Kbenzene-water:
    Not established/determined
  • Log Kow (estimated):
    0.73
  • Melting Point:
    95°F to 104°F (35°C to 40°C)
  • Molecular Mass:
    113.93
  • Soluble In:
    Highly soluble in most organic solvents
  • Specific Gravity:
    Not established/determined
  • Vapor Pressure:
    Liquid: 13 mm Hg at 104°F (40°C)
    Solid: 11.2 mm Hg at 77°F (25°C)
  • Volatility:
    1,800 mg/m3 at 68°F (20°C)
    76,000 mg/m3 at 104°F (40°C)
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Hazardous Materials Warning Labels/Placards

  • Shipping Name:
    Toxic solids, organic, n.o.s.
  • Identification Number:
    2811 (Guide 154)
  • Hazardous Class or Division:
    6.1
  • Subsidiary Hazardous Class or Division:
  • Label:
    Poison (Toxic)
    PG III
  • Placard Image:
    dot_class6_pgiii dot_class6_poison dot_class6_toxic
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Trade Names and Other Synonyms

  • Carbonimidic dichloride, hydroxy-
  • Dichloroformaldehyde oxime
  • Dichloroformaldoxime
  • Dichloroformossina
  • Dichloroformoxine
  • Dichlorophormoxine
  • Phosgene, oxime
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Who to Contact in an Emergency

In the event of a poison emergency, call the poison center immediately at 1-800-222-1222. If the person who is poisoned cannot wake up, has a hard time breathing, or has convulsions, call 911 emergency services.

For information on who to contact in an emergency, see the CDC website at emergency.cdc.gov or call the CDC public response hotline at (888) 246-2675 (English), (888) 246-2857 (Español), or (866) 874-2646 (TTY).

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Important Notice

The user should verify compliance of the cards with the relevant STATE or TERRITORY legislation before use. NIOSH, CDC 2003.

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