Hydrogen Chloride laser cleaning visualization showing process effects
Ikmanda Roswati
Ikmanda RoswatiPh.D.Indonesia
Ultrafast Laser Physics and Material Interactions
Published
Jan 6, 2026

Hydrogen Chloride Compound

Hydrogen Chloride Compound safety information for laser cleaning. Health hazards, exposure limits, and protective equipment requirements.

Chemical Properties

Chemical Identity

CAS Number
7647-01-0
Formula
HCl
Molecular Weight
36.46 g/mol

Exposure Limits Comparison

Health Effects

Severe Respiratory Irritation
Yes
Corrosive To Tissue
Yes
Pulmonary Edema
Yes
Tooth Erosion
Yes
Detection Monitoring
SensorTypes
  • Electrochemical
  • Infrared
  • Colorimetric
DetectionRange
0-50 ppm typical
AlarmSetpoints
Low
2 ppm (ACGIH ceiling)
High
5 ppm (OSHA/NIOSH ceiling)
Evacuate
50 ppm (NIOSH IDLH)
ColorimetricTubes
  • Dräger HCl 0.2/a
  • Gastec 14L
  • Kitagawa 183
AnalyticalMethods
MethodTechniqueDetectionLimit
NIOSH 7903Ion chromatography0.02 ppm
OSHA ID-173Ion chromatography0.01 ppm
OdorThreshold
0.8-5 ppm - provides adequate warning but close to toxic levels
Environmental Impact
AquaticToxicity
Toxic to aquatic life. LC50 (fish, 96h): 100-300 mg/L HCl solution. Acidifies water.
Biodegradability
Not biodegradable. Dissolves in water forming hydrochloric acid.
Bioaccumulation
Does not bioaccumulate.
SoilMobility
High mobility as gas. Deposits as chloride salts. Acidifies soil.
AtmosphericFate
Rapidly dissolves in atmospheric moisture. Forms hydrochloric acid droplets. Washed out by rain.
OzoneDepletion
false
ReportableReleases
Water
5000 lbs to navigable waters
Air
5000 lbs/day (CERCLA RQ)
Ppe Requirements
Respiratory
SCBA or supplied-air respirator for >5 ppm or unknown concentrations. Air-purifying with acid gas cartridge acceptable for ≤5 ppm with escape provisions.
Eye Protection
Chemical safety goggles, full face shield mandatory. Extremely corrosive to eyes.
Skin Protection
Neoprene or butyl rubber gloves, chemical-resistant suit. HCl is highly corrosive to skin.
Reactivity
Stability
Stable as dry gas. Forms corrosive hydrochloric acid with moisture.
Polymerization
Will not polymerize
IncompatibleMaterials
  • Metals (Al, Zn, Fe - generates H2)
  • Strong bases
  • Strong oxidizers
  • Alcohols
  • Amines
  • Aldehydes
  • Metal carbides
HazardousDecomposition
  • Hydrogen chloride gas
  • Chlorine (if heated with oxidizers)
ConditionsToAvoid
  • Moisture
  • Heat
  • Incompatible materials
  • Metals
ReactivityHazard
Reacts violently with metals producing flammable hydrogen gas. Reacts exothermically with bases. Forms corrosive mist in humid air.
Regulatory Classification
UnNumber
UN1050 (anhydrous), UN1789 (solution)
DotHazardClass
2.3 (Toxic gas), 8 (Corrosive)
DotLabel
Poison Gas, Corrosive
NfpaCodes
Health
3
Flammability
0
Reactivity
0
Instability
0
EpaHazardCategories
  • Acute toxicity (inhalation)
  • Skin corrosion
  • Serious eye damage
SaraTitleIii
true
CerclaRq
5000 pounds (2270 kg)

Contaminants That Produce Hydrogen Chloride

Hydrogen Chloride is produced as a gaseous or particulate byproduct during laser ablation of contaminated surfaces. The generation rate and chemical form depend on the source contaminant and substrate combination. Proper exhaust ventilation and gas monitoring ensure safe working concentrations in laser cleaning enclosures.
No metadata available

Degraded Polymer Deposits

No metadata available

Adhesive Residue / Tape Marks Laser Cleaning

Chemical Properties

Molecular formula, CAS number, molecular weight, and chemical structure
Type
chemical_properties
Id
hydrogen-chloride-physical-data

Physical Properties

Chemical and physical characteristics
BoilingPoint
-85.05°C (-121°F)
MeltingPoint
-114.17°C (-173.5°F)
VaporPressure
>760 mmHg @ 20°C (gas)
VaporDensity
1.27 (Air=1)
SpecificGravity
1.19 (liquid @ -26°C)
FlashPoint
Not applicable (non-flammable)
AutoignitionTemp
Not applicable
ExplosiveLimits
Not applicable
Appearance
Colorless gas, colorless to light yellow liquid (anhydrous)
Odor
Pungent, irritating odor @ 0.8-5 ppm

Alternative Names

Synonyms and chemical identifiers
Synonyms
  • Hydrochloric acid gas
  • Muriatic acid gas
  • Chlorohydric acid
  • Anhydrous hydrogen chloride
CommonTradeNames
    OtherIdentifiers
    RtecsNumber
    MW4025000
    EcNumber
    231-595-7
    PubchemCid
    313

    Health Effects

    Adverse health impacts from exposure to this compound
    Route
    inhalation
    Effect
    Severe irritation of respiratory tract, coughing, choking, and potential pulmonary edema
    Severity
    severe
    Onset
    immediate
    Route
    skin_contact
    Effect
    Chemical burns and severe irritation leading to tissue damage
    Severity
    severe
    Onset
    immediate
    Route
    eye_contact
    Effect
    Intense pain, lacrimation, and corneal burns with risk of permanent vision impairment
    Severity
    severe
    Onset
    immediate
    Route
    ingestion
    Effect
    Burns to mouth, esophagus, and stomach with risk of perforation and systemic toxicity
    Severity
    severe
    Onset
    immediate

    Personal Protective Equipment

    Required safety equipment for handling this compound
    Respiratory
    SCBA or supplied-air respirator for >5 ppm or unknown concentrations. Air-purifying with acid gas cartridge acceptable for ≤5 ppm with escape provisions.
    Skin
    Neoprene or butyl rubber gloves, chemical-resistant suit. HCl is highly corrosive to skin.
    Eye
    Chemical safety goggles, full face shield mandatory. Extremely corrosive to eyes.
    MinimumLevel
    Level C for known <5 ppm, Level B for >5 ppm or liquid HCl
    SpecialNotes
    Extremely corrosive. Causes severe burns on contact. Fumes in moist air. Emergency eyewash/shower within 10 seconds mandatory. Liquid causes frostbite (cryogenic).

    Exposure Limits

    OSHA, NIOSH, and ACGIH exposure thresholds
    OshaPelMgM3
    7
    NioshRelPpm
    5
    NioshRelMgM3
    7
    AcgihTlvMgM3
    2
    WorkplaceExposure
    OshaPel
    twa8Hr: null
    stel15Min: null
    ceiling: 5 ppm
    NioshRel
    twa8Hr: null
    stel15Min: null
    ceiling: 5 ppm
    idlh: 50 ppm
    AcgihTlv
    twa8Hr: 2 ppm
    stel15Min: 5 ppm
    ceiling: null
    BiologicalExposureIndices

    Storage Requirements

    Safe storage conditions and compatibility
    TemperatureRange
    Store cylinders <52°C. Keep away from heat.
    Ventilation
    Outdoor storage preferred. Indoor: mechanical ventilation with acid-resistant ductwork. HCl gas detection required.
    Incompatibilities
    • Metals (generates hydrogen)
    • Bases
    • Oxidizers
    • Alcohols
    • Amines
    • Aldehydes
    • Metal carbides
    ContainerMaterial
    Steel cylinders for compressed gas. Glass, PVC, PVDF, or PTFE for liquid.
    Segregation
    Separate from bases, oxidizers, and metals. Corrosive storage area.
    QuantityLimits
    Per fire code. Minimize indoor storage of cylinders.
    SpecialRequirements
    Cylinder restraints mandatory. Leak detection system required. Post "CORROSIVE GAS" signs. Emergency eyewash/shower within 25 feet. Store in cool, dry area. Protect from physical damage.

    Emergency Response

    Procedures for spills, exposure, and incidents
    FireHazard
    Non-flammable. Cylinders may explode when heated. Corrosive decomposition products.
    FireSuppression
    Do not use water directly on HCl gas - forms corrosive hydrochloric acid mist. Cool cylinders with water spray from safe distance.
    SpillProcedures
    EVACUATE. Ventilate area. SCBA required for >5 ppm. Neutralize with soda ash, lime, or sodium bicarbonate. Contain with dry sand or earth. Decontaminate equipment.
    ExposureImmediateActions
    Remove to fresh air immediately. Eyes: flush with water for 15+ minutes - GET MEDICAL HELP IMMEDIATELY. Skin: remove contaminated clothing, flush with water for 15 minutes. If inhaled: administer oxygen. Seek immediate medical attention - corrosive injury.
    EnvironmentalHazards
    Toxic to aquatic life. Forms hydrochloric acid in water. Report releases >5000 lbs.
    SpecialHazards
    Extremely corrosive to all tissues. Forms dense white corrosive mist in moist air. Reacts with metals producing flammable hydrogen gas. Causes severe burns, permanent eye damage, respiratory tract damage.

    Regulatory Classification

    DOT, UN, and NFPA hazard classifications
    UnNumber
    UN1050 (anhydrous), UN1789 (solution)
    DotHazardClass
    2.3 (Toxic gas), 8 (Corrosive)
    DotLabel
    Poison Gas, Corrosive
    NfpaCodes
    Health
    3
    Flammability
    0
    Reactivity
    0
    Special
    null
    Instability
    0
    EpaHazardCategories
    • Acute toxicity (inhalation)
    • Skin corrosion
    • Serious eye damage
    SaraTitleIii
    true
    CerclaRq
    5000 pounds (2270 kg)

    Environmental Impact

    Toxicity, biodegradability, and environmental fate
    AquaticToxicity
    Toxic to aquatic life. LC50 (fish, 96h): 100-300 mg/L HCl solution. Acidifies water.
    Biodegradability
    Not biodegradable. Dissolves in water forming hydrochloric acid.
    Bioaccumulation
    Does not bioaccumulate.
    SoilMobility
    High mobility as gas. Deposits as chloride salts. Acidifies soil.
    AtmosphericFate
    Rapidly dissolves in atmospheric moisture. Forms hydrochloric acid droplets. Washed out by rain.
    OzoneDepletion
    false
    ReportableReleases
    Water
    5000 lbs to navigable waters
    Air
    5000 lbs/day (CERCLA RQ)

    FAQ

    Common Questions and Answers
    How can I detect and monitor HCl gas exposure during laser cleaning to stay within safe limits?
    Use portable gas detectors equipped with electrochemical sensors specific to HCl, placed in the breathing zone and work area, to monitor concentrations in real-time; the OSHA permissible exposure limit (PEL) is 5 ppm as a ceiling limit, meaning levels should never exceed this to avoid immediate respiratory irritation. Calibrate detectors daily and set alarms for 1-2 ppm to allow early evacuation or ventilation adjustments, especially since HCl from laser ablation can rapidly irritate eyes, skin, and lungs far more aggressively than milder acids like acetic. If levels approach the PEL, immediately don a full-face respirator with acid gas cartridges and enhance local exhaust ventilation to dilute the corrosive gas.

    Detection & Monitoring

    Methods for detecting and measuring this compound
    SensorTypes
    • Electrochemical
    • Infrared
    • Colorimetric
    DetectionRange
    0-50 ppm typical
    AlarmSetpoints
    Low
    2 ppm (ACGIH ceiling)
    High
    5 ppm (OSHA/NIOSH ceiling)
    Evacuate
    50 ppm (NIOSH IDLH)
    ColorimetricTubes
    • Dräger HCl 0.2/a
    • Gastec 14L
    • Kitagawa 183
    AnalyticalMethods
    • [object Object]
    • [object Object]
    OdorThreshold
    0.8-5 ppm - provides adequate warning but close to toxic levels

    Reactivity

    Chemical reactivity and incompatibilities
    Stability
    Stable as dry gas. Forms corrosive hydrochloric acid with moisture.
    Polymerization
    Will not polymerize
    IncompatibleMaterials
    • Metals (Al, Zn, Fe - generates H2)
    • Strong bases
    • Strong oxidizers
    • Alcohols
    • Amines
    • Aldehydes
    • Metal carbides
    HazardousDecomposition
    • Hydrogen chloride gas
    • Chlorine (if heated with oxidizers)
    ConditionsToAvoid
    • Moisture
    • Heat
    • Incompatible materials
    • Metals
    ReactivityHazard
    Reacts violently with metals producing flammable hydrogen gas. Reacts exothermically with bases. Forms corrosive mist in humid air.

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