Chemical Properties

Chemical Identity

CAS Number

124-38-9

Formula

CO₂

Molecular Weight

44.01 g/mol

Exposure Limits Comparison

OSHA PEL

5000 ppm

NIOSH REL

5000 ppm

ACGIH TLV

5000 ppm

Health Effects

Asphyxiation At High Concentration

Yes

Respiratory Stimulation

Yes

Narcosis

Yes

Generally Non Toxic

Yes

Carbon Dioxide (CO₂) safety information

Comprehensive safety and handling requirements

Detection Monitoring

Sensor Types

Infrared (NDIR)
Electrochemical
Thermal conductivity

Detection Range

0-50,000 ppm typical (0-5%)

Alarm Setpoints

Low	5000 ppm (0.5%) - OSHA TWA/NIOSH REL
High	10,000 ppm (1%) - physiological effects begin
Evacuate	40,000 ppm (4%) - NIOSH IDLH

Colorimetric Tubes

Dräger CO2 0.01%/a
Gastec 2L
Kitagawa 126

Analytical Methods

Method	Technique	Detection Limit
NIOSH 6603	NDIR (Non-dispersive infrared)	50 ppm
Detector tubes	Colorimetric	0.01%

Odor Threshold

Not applicable - odorless at all concentrations. No warning property. MUST use instruments.

Environmental Impact

Aquatic Toxicity

Low direct toxicity. LC50 (fish): >100 mg/L. Acidifies water (forms carbonic acid). High levels suffocate aquatic life.

Biodegradability

Not applicable (natural component of carbon cycle).

Bioaccumulation

Does not bioaccumulate.

Soil Mobility

High mobility as gas. Absorbed by alkaline soils forming carbonates.

Atmospheric Fate

Major greenhouse gas. Atmospheric residence: 30-95 years. Essential for photosynthesis. Removed by plants and ocean absorption.

Ozone Depletion

false

Global Warming Potential

1 (reference gas)

Reportable Releases

Water	Not reportable
Air	Not reportable (natural atmospheric component)

Ppe Requirements

Respiratory	SCBA for >5% (50,000 ppm) or oxygen-deficient atmospheres. Not required for normal ambient levels.
Eye Protection	Safety glasses for dry ice handling. No protection needed for gas.
Skin Protection	Insulated gloves for liquid/solid CO2 (dry ice) - cryogenic hazard. No protection needed for gas at normal levels.

Reactivity

Stability	Stable under normal conditions.
Polymerization	Will not polymerize
Incompatible Materials	Reactive metals (cesium, sodium, potassium) Metal acetylides Strong bases (forms carbonates) Ammonia (forms ammonium carbamate)
Hazardous Decomposition	Carbon dioxide (already stable) Carbon monoxide (only at very high temperatures)
Conditions To Avoid	High heat (cylinder explosion) Reactive metals
Reactivity Hazard	Generally non-reactive. Reacts with strong bases. May react with reactive metals. Solid CO2 causes embrittlement of some materials.

Regulatory Classification

Un Number

UN1013 (compressed gas), UN1845 (solid/dry ice)

Dot Hazard Class

2.2 (Non-flammable gas)

Dot Label

Non-flammable Gas

Nfpa Codes

Health	1
Flammability	0
Reactivity	0
Special	SA (Simple Asphyxiant)

Epa Hazard Categories

Simple asphyxiant
Cryogenic hazard (dry ice)

Sara Title Iii

false

Storage Requirements

Temperature Range	Store cylinders <52°C. Dry ice requires insulated storage <-78°C.
Ventilation	Good ventilation essential. Outdoor storage preferred for large quantities. Monitor oxygen levels in storage areas.
Incompatibilities	Reactive metals (cesium, sodium, potassium) Metal acetylides Bases (reacts forming carbonates)
Container Material	Steel cylinders for compressed gas. Insulated containers for dry ice.
Segregation	None required. Keep away from reactive metals.
Quantity Limits	Cylinders per fire code. Dry ice quantities limited by storage capacity.
Special Requirements	Cylinder restraints mandatory. Oxygen monitoring in storage areas. Post "SIMPLE ASPHYXIANT" signs. Adequate ventilation critical. Never store in confined spaces without ventilation and O2 monitoring.

Produced From Contaminants

Exposure Limits

Regulatory exposure thresholds and safe concentration levels

Osha Pel Ppm: 5000
Osha Pel Mg M3: 9000
Niosh Rel Ppm: 5000
Niosh Rel Mg M3: 9000
Acgih Tlv Ppm: 5000
Acgih Tlv Mg M3: 9000
Workplace Exposure: Osha Pel
twa_8hr: 5000 ppm (9000 mg/m³)
stel_15min: 30,000 ppm (54,000 mg/m³)
ceiling: null
Niosh Rel
twa_8hr: 5000 ppm (9000 mg/m³)
stel_15min: 30,000 ppm (54,000 mg/m³)
ceiling: null
idlh: 40,000 ppm (4%)
Acgih Tlv
twa_8hr: 5000 ppm
stel_15min: 30,000 ppm
ceiling: null
Biological Exposure Indices

Physical Properties

Physical characteristics and state information

Boiling Point: -78.5°C (-109.3°F) sublimes at 1 atm
Melting Point: -56.6°C (-69.9°F) @ 5.1 atm
Vapor Pressure: 830 psi @ 20°C
Vapor Density: 1.52 (Air=1)
Specific Gravity: 1.56 (solid @ -79°C), 0.77 (liquid @ 0°C)
Flash Point: Not applicable (non-flammable)
Autoignition Temp: Not applicable
Explosive Limits: Not applicable (does not burn)
Appearance: Colorless gas, white solid (dry ice)
Odor: Odorless

Reactivity

Chemical reactivity and compatibility with other substances

Stability: Stable under normal conditions.
Polymerization: Will not polymerize
Incompatible Materials: Reactive metals (cesium, sodium, potassium)
Metal acetylides
Strong bases (forms carbonates)
Ammonia (forms ammonium carbamate)
Hazardous Decomposition: Carbon dioxide (already stable)
Carbon monoxide (only at very high temperatures)
Conditions To Avoid: High heat (cylinder explosion)
Reactive metals
Reactivity Hazard: Generally non-reactive. Reacts with strong bases. May react with reactive metals. Solid CO2 causes embrittlement of some materials.

Synonyms & Identifiers

Alternative names and chemical identifiers (CAS numbers)

Synonyms: CO2
Carbonic anhydride
Carbonic acid gas
Dry ice (solid)
Common Trade Names: Dry ice
Other Identifiers: Rtecs Number
FF6400000
Ec Number
204-696-9
Pubchem Cid
280