Chloroacetophenone (CN): Riot Control/Tear Agent

CAS #:
532-27-4

RTECS #: AM6300000

UN #: 1697 (Guide 153)

Common Names:

  • 2-Chloro-1-phenylethanone
  • 2-Chloroacetophenone
  • alpha-Chloroacetophenone
  • Chemical mace
  • Chloromethyl phenyl ketone
  • Phenyl chloromethylketone
  • Tear gas

Agent Characteristics

Colorless to gray or white crystalline solid. May appear as blue-white cloud at point of release.

Chloroacetophenone (CN), the active ingredient of Mace™, is a riot control or tear agent used by the military (military designation CN) and law enforcement. It is also available to the general public. The United States considers agent CN and its mixtures with various chemicals to be obsolete for military deployment. Chloroacetophenone (CN) has a sharp, irritating odor (sometimes described as “apple blossoms” odor). It may be dissolved in a solvent.

  • Indoor Air: Chloroacetophenone (CN) can be released into indoor air as fine particulate smoke, vapor, or liquid spray (aerosol).
  • Water: Chloroacetophenone (CN) can be used to contaminate water.
  • Food: Chloroacetophenone (CN) may be used to contaminate food.
  • Outdoor Air: Chloroacetophenone (CN) can be released into outdoor air as fine particulate smoke, vapor from burning munitions, or liquid spray (aerosol).
  • Agricultural: If chloroacetophenone (CN) is released as a liquid spray (aerosol), it has the potential to contaminate agricultural products. If chloroacetophenone (CN) is released as particulate smoke or a vapor, it is highly unlikely to contaminate agricultural products.

Chloroacetophenone (CN) can be absorbed by ingestion and inhalation. It may cause localized irritation of the gastrointestinal tract, respiratory tract, and upon contact with the skin or eyes.


Personal Protective Equipment

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.

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.

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.

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.

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.

Emergency Response

  • Chloroacetophenone (CN) is incompatible with strong oxidants.
  • Chloroacetophenone (CN) reacts slowly with metals, causing mild corrosion.
  • Contact with metals may evolve flammable hydrogen gas.
  • When heated, vapors may form explosive mixtures with air, presenting an explosion hazard indoors, outdoors, and in sewers.
  • Containers may explode when heated.
  • Decomposes on burning, producing toxic and corrosive fumes, including hydrogen chloride.
  • Upper and lower explosive (flammable) limits are not establish/determined.
  • Chloroacetophenone (CN) is combustible.
  • The agent may burn but does not ignite readily.
  • Fire may produce irritating, corrosive, and/or toxic gases.
  • The agent may be transported in a molten form.
  • 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 the 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).
  • 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 chloroacetophenone (CN) 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 chloroacetophenone (CN) is used as a weapon
  • First isolate in all directions: 400 ft (120 m).
  • Then protect persons downwind during the day: 0.7 mi (1.2 km).
  • Then protect persons downwind during the night: 2.0 mi (3.3 km).
  • Vapors may be 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.
  • Health: 2
  • Flammability: 1
  • Reactivity: 0
  • Special:

Health: 2, Flammability: 1, Reactivity: 0, Special:

  • OSHA: Not established/determined
  • NIOSH: P&CAM291 (II-5)
References are provided for the convenience of the reader and do not imply endorsement by NIOSH.
  • AIR MATRIX
    Allison G, McLeod CW [1997]. Characterization of tear gas residues by ion mobility spectrometry. Appl Spectroscopy 51(12):1880-1889.Babakhanian RV, Bushuev ES, Gustyleva LK, Ignat’ev IuA, Kul’bitskii GN [1996]. The gas chromatographic analysis of irritating substances. Sud Med Ekspert 39(1):28-29. (Article in Russian.)D’Agostino PA [1996]. Capillary column gas chromatography-tandem mass spectrometric characterization of irritants. Gov Reports Announcements and Index (GRA&I), Issue 03.

    D’Agostino PA, Provost LR [1995]. Analysis of irritants by capillary column gas chromatography-tandem mass spectrometry. J Chromatogr A 695(1):65-73.

    Ferslew KE, Orcutt RH, Hagardorn AN [1986]. Spectral differentiation and gas chromatographic/mass spectrometric analysis of the lacrimators 2-chloroacetophenone and o-chlorobenzylidene malononitrile. J Forensic Sci 31(2):658-665.

    Gandhe BR, Malhotra RC, Gutch PK [1989]. Gas chromatographic retention indices of tear gases on capillary columns. J Chromatogr 479(1):165-169.

    Hancock JR, Lough CE, Hicken RP [1992]. Development of a field sampling kit for chemical warfare agents. Gov Reports Announcements and Index (GRA&I), Issue 09.

    Lee DS, Kim NS [2002]. Identification of fragrances from chestnut blossom by gas chromatography-ion trap mass spectrometry. Bull Korean Chem Soc 23(11):1647-1650.

    NIOSH [1994]. NMAM Method 2553: Ketones II. In: NIOSH manual of analytical methods. 4th ed. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety an Health, DHHS (NIOSH) Publication No. 1994-113.

    Potter W [1982]. Chloroacetophenone. OSHA Stopgap Method. Salt Lake City, UT: U.S. Department of Labor, OSHA Analytical Laboratory, Solvents Branch.

  • 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
    Huber JFK, Kenndler E, Reich G, Hack W, Wolf J [1993]. Optimal selection of gas chromatographic columns for the analytical control of chemical warfare agents by application of the information theory to retention data. Anal Chem 65(20):2903-2906.

Signs/Symptoms

Exposure to chloroacetophenone (CN) generally causes instantaneous irritation of the eyes, respiratory tract, and skin. Initial irritation typically resolves within 15 to 30 minutes following decontamination. Eye irritation may persist if the eyes are rubbed. Eye redness and accumulation of fluid in the tissues surrounding the eye (periorbital edema) may take 1 to 2 days to resolve. Respiratory adverse health effects, such as accumulation of fluid in the lungs (pulmonary edema), may occur immediately after exposure or can be delayed up to 12 to 24 hours. Adverse effects to the skin occurring within 24 hours of exposure can be severe and may include redness, blistering, and broken blisters, with variable amounts of skin loss.

Adverse health effects due to chloroacetophenone (CN) exposure are dependent on concentration, duration of exposure, proximity to the exposure source, and location at time of exposure (indoors vs. outdoors). Exposure to extremely high levels, such as in an enclosed space and/or for a prolonged period of time, may cause severe respiratory effects and rarely death. Rapid heart rate (tachycardia), mildly elevated blood pressure (hypertension), agitation, and fainting (syncope), may occur as a result of pain, fear, or panic.

  • Threshold concentrations: Immediate burning pain, spasmodic blinking (blepharospasm), tear production (lacrimation), eye redness, runny nose (rhinorrhea), coughing, sneezing, and pain, but usually no long term tissue damage.
  • Severe: Inflammation of the cornea (keratitis), inflammation of the conjunctiva (conjunctivitis), chemical burns, loss of the outer layer of the cornea (corneal epithelium), sensitivity to light (photophobia), and blurred vision. Partial eye opacity is possible and may be permanent.
  • Droplets of liquid or particles in the eyes may be corrosive and produce burns like those of a strong acid.
  • Projectile particles may injure any part of the eye causing perforation, which may lead to permanent partial vision loss.
  • Discomfort in the middle abdominal (epigastric) region, burping, and metallic taste with burning sensation.
  • Ingestion is unlikely to occur.
  • Mild to moderate: Runny nose (rhinorrhea), coughing, sneezing, chest tightness, vocal cord spasm causing difficulty breathing, shortness of breath, and a choking feeling, burning sensation and pain of the nose and mouth, noisy breathing such as wheezing, salivation, metallic taste, nausea, vomiting (emesis).
  • Severe: Fluid build-up in the lungs (pulmonary edema) up to 12 to 24 hours after exposure, immediate or delayed narrowing of the large airways (bronchospasm), inflammation and consolidation of the airspaces in the lung (bronchopneumonia).
  • Pain, fear, and panic may result in agitation, fainting (syncope), increased heart rate (tachycardia), and/or mildly elevated blood pressure (hypertension).
  • Mild to moderate: Irritation and pain. Moisture from humidity, sweat, or decontaminating water, may temporarily increase irritation and pain.
  • Severe: Delayed redness (erythema), blistering (vesication), and denuded areas.

Decontamination

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.

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.

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.

First Aid

Initial treatment is primarily supportive. Most patient/victims require no medical attention and casualties are rare. In cases of inhalation, patient/victims with mild to moderate exposures generally improve rapidly following removal from the source of exposure and require no additional treatment. Patient/victims with more severe exposures require hospital admission for observation of lung injury or accumulation of fluid in the lungs (pulmonary edema) and skin injury.

There is no antidote for chloroacetophenone (CN) toxicity.

  • Immediately remove the patient/victim from the source of exposure.
  • Effects are normally self-limiting and do not require treatment.
  • For large particles or droplets in the eye, immediately wash eyes with large amounts of tepid water for at least 15 minutes.
  • Check eyes for the presence of particles of agent or pieces of tear gas canister. (Serious damage can occur if these are left in the eye.) Consider use of an eye cage to prevent direct pressure on the eye.
  • If large particles or droplets of agents are found, treatment for corrosive materials may be required.
  • Ophthalmic corticosteroid ointment may be applied after complete decontamination.
  • Seek medical attention immediately.
  • Immediately remove the patient/victim from the source of exposure.
  • Ensure that the patient/victim has an unobstructed airway.
  • Do not induce vomiting (emesis).
  • Seek medical attention immediately.
  • 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 vocal cords closing and preventing air from entering the lungs (laryngospasm), and treat it if it occurs.
  • Monitor the patient/victim for signs of accumulation of fluid in the lungs (pulmonary edema), such as difficulty breathing or shortness of breath (dyspnea) and chest tightness.
  • Seek medical attention immediately.
  • Immediately remove the patient/victim from the source of exposure.
  • See the Decontamination section for patient/victim decontamination procedures.
  • Early reddening (erythema) and a stinging sensation are transient and do not require treatment.
  • Seek medical attention immediately.

Long-Term Implications

In the rare event of pulmonary effects following massive exposure, evacuation for hospital care is required. Severe respiratory effects, including accumulation of fluid in the lungs (pulmonary edema), may not manifest until 12 to 24 hours after exposure. Monitoring for respiratory complications has been recommended for patient/victims with marked symptoms or who have pre-existing conditions such as hyperreactive airways (asthma). Patient/victims with severe eye exposures should be observed closely for development of eye effects (corneal opacity and iritis). For skin exposure, delayed erythema (irritant dermatitis) may be treated with calamine lotion or a topical corticosteroid depending on severity. Cases with blisters should be managed as a second degree burn. Secondary infections are treated with appropriate antibiotics.

Severe exposures, such as those in enclosed spaces, may cause permanent damage to the eyes, including blindness. Severe reactions of the eyes or the skin may take days or weeks to heal, depending upon severity. Headache and mental depression may appear as late effects.

There is inadequate information to assess the carcinogenic potential of chloroacetophenone (CN). Information is unavailable about the developmental toxicity, or reproductive toxicity risk from chronic or repeated exposure to chloroacetophenone (CN). Chronic or repeated exposure to chloroacetophenone (CN) may lead to eye problems including scarring, glaucoma, and cataracts. It may also cause breathing problems such as asthma. Prolonged contact with skin may cause dermatitis or skin sensitization.


On-Site Fatalities

  • 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.
  • 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.

Occupational Exposure Limits

  • NIOSH REL:
    • TWA: 0.3 mg/m3 (0.05 ppm)
  • OSHA PEL:
    • TWA: 0.3 mg/m3 (0.05 ppm)
  • ACGIH TLV:
    • 0.32 mg/m3 (0.05 ppm)
  • NIOSH IDLH: 15 mg/m3
  • 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

Acute Exposure Guidelines

Acute Exposure Guidelines
5 min 10 min 30 min 1 hr 4 hr 8 hr
AEGL 1
(discomfort, non-disabling) – mg/m3
Not established/ determined Not established/ determined Not established/ determined Not established/ determined Not established/ determined Not established/ determined
AEGL 2
(irreversible or other serious, long-lasting effects or impaired ability to escape) – mg/m3
Not established/ determined Not established/ determined Not established/ determined Not established/ determined Not established/ determined Not established/ determined
AEGL 3
(life-threatening effects or death) – mg/m3
Not established/ determined Not established/ determined Not established/ determined Not established/ determined Not established/ determined Not established/ determined

Decontamination (Environment and Equipment)

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, and turn leaking containers so that gas rather than liquid escapes.
  • Prevent entry into waterways, sewers, basements, or confined areas.
  • Isolate the area until gas has dispersed.
  • Ventilate the area.

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

Agent Properties

  • Chemical Formula:
    C8H7ClO
  • Aqueous solubility:
    Slightly soluble
  • Boiling Point:
    472° to 473°F (244° to 245°C)
  • Density:
    Solid: 1.32 at 20°C
    Liquid: 1.19 at 58°C
    Vapor: 5.3
  • Flammability:
    Combustible solid
  • Flashpoint:
    244°F (118°C)
  • Ionization potential:

    9.44 eV

  • Log Kbenzene-water:
    Not established/determined
  • Log Kow (estimated):
    1.93
  • Melting Point:
    136° to 138°F (58° to 59°C)
  • Molecular Mass:
    154.60
  • Soluble In:

    Alcohol
    Benzene
    Ether
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  • Specific Gravity:
    1.32
  • Vapor Pressure:
    .0054 mm Hg at 68°F (20°C)
  • Volatility:
    2.36 mg/m3 at 32°F (0°C)
    34.3 mg/m3 at 68°F (20°C)
    1,060 mg/m3 at 125°F (51.7°C)

Hazardous Materials Warning Labels/Placards

  • Shipping Name:
    Chloroacetophenone (CN), liquid or solid
  • Identification Number:
    1697 (Guide 153)
  • Hazardous Class or Division:
    6.1
  • Subsidiary Hazardous Class or Division:
  • Label:
    Poison (Toxic)
  • Placard Image:
    dot_class6_poison dot_class6_toxic

Trade Names and Other Synonyms

  • 1-Chloroacetophenone
  • 2-Chloro-acetophenone
  • a-Chloroacetophenone
  • CAF
  • CAP
  • Ethanone, 2-chloro-1-phenyl
  • Phenyl chloromethyl ketone
  • omega-Chloroacetophenone
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).

Important Notice

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