Propane

Classification

Flammable gas, Category 1A; Gas under pressure (liquefied gas); Simple asphyxiant

Hazard statements

• H220 Extremely flammable gas.
• H280 Contains gas under pressure; may explode if heated.
• May displace oxygen and cause rapid suffocation (asphyxiant hazard; no H code).

Key precautionary statements

• P210 Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
• P377 Leaking gas fire: Do not extinguish, unless leak can be stopped safely.
• P381 In case of leakage, eliminate all ignition sources.
• P410+P403 Protect from sunlight. Store in a well-ventilated place.

The federal OSHA general industry PEL is 1000 ppm (1800 mg/m³) as an 8-hour TWA, from Table Z-1. OSHA's construction and shipyard tables give no numeric limit and instead treat propane as a simple asphyxiant, where the limiting factor is available oxygen. NIOSH recommends 1000 ppm as a 10-hour TWA. ACGIH withdrew its propane TLV in 2013 and now points to its guidance on minimal oxygen content. The IDLH of 2100 ppm is set at 10% of the lower explosive limit, so fire and explosion, not toxicity, are the main concern. Use combustible gas detection to keep levels well below the LEL. State OSHA plans may set different limits.

• Appearance: Colorless gas; shipped and stored as a liquefied gas under pressure
• Odor: Odorless when pure; fuel-grade propane has an odorant added so leaks can be smelled
• Molecular weight: 44.1
• Boiling point: -44°F (-42°C)
• Freezing point: -306°F (-188°C)
• Flash point: Not applicable (flammable gas); listed as -156°F (-104°C) in the OSHA database
• Autoignition temperature: 842°F (450°C)
• Explosive limits: LEL 2.1%, UEL 9.5%
• Vapor pressure: 8.4 atm at 70°F
• Relative gas density: 1.55 (heavier than air; collects in low spots)
• Water solubility: 0.01% (practically insoluble)

Inhalation

Propane has low toxicity, but very high concentrations push out oxygen. Symptoms include dizziness, headache, confusion, excitement, poor coordination, nausea and, in an oxygen-deficient atmosphere, unconsciousness and death. Concentrations that are dangerous to breathe are already far inside the flammable range.

Skin

The gas does not harm skin. Contact with the liquid or with rapidly escaping gas causes frostbite.

Eyes

Contact with the liquid or escaping gas can freeze eye tissue.

Ingestion

Not a relevant route for a gas.

Target organs

Central nervous system

Long-term effects

No chronic health effects are known. A major indirect hazard is carbon monoxide from heaters, forklifts and other propane-burning equipment used indoors with poor ventilation.

Gloves

Insulated gloves when connecting cylinders or handling liquid. The New Jersey Department of Health lists insulated nitrile gloves, with more than 8 hours of breakthrough time for propane.

Eyes and face

Safety glasses or non-vented goggles when changing cylinders; add a face shield where liquid could spray.

Respiratory

Air-purifying respirators do not protect against propane or low oxygen. NIOSH lists supplied-air respirators or a full-facepiece SCBA up to 2100 ppm, and a pressure-demand SCBA for emergencies or unknown concentrations. Do not enter atmospheres near the LEL at all.

Clothing

Flame-resistant clothing where a flash fire is possible. Remove clothing promptly if it becomes wet with liquid propane, because it is flammable.

Store cylinders upright and secured, outdoors or in a well-ventilated area, away from heat, sunlight, ignition sources and building openings. Keep cylinders below 125°F (52°C) and close valves when not in use. Do not store cylinders in basements or pits, because leaking gas sinks and collects.

Follow OSHA and NFPA 58 rules for LP-gas systems, use leak-tested fittings, and control ignition sources. Treat torch and heater use as hot work, and test the air before and during work in a confined space where propane is used. Burn propane equipment indoors only with enough ventilation to remove carbon monoxide.

Keep away from

• Strong oxidizers (such as peroxides, nitrates, perchlorates, chlorine and fluorine)

• Evacuate the area and eliminate all ignition sources.
• Stop the flow of gas if it can be done safely; turn a leaking cylinder so the leak is on top, letting gas rather than liquid escape.
• Ventilate the area and keep gas out of sewers, basements and confined spaces.
• Monitor for flammable levels and confirm oxygen is at least 19.5% before re-entry.
• Use water spray to disperse vapor and protect people trying to stop the leak.
• Follow ERG Guide 115.

Suitable extinguishing media

• Do not put out a leaking gas fire unless the leak can be stopped safely
• Large amounts of water spray to cool tanks and cylinders
• Dry chemical or carbon dioxide for small fires once the gas is shut off

Special hazards

Extremely flammable. Gas is heavier than air, spreads along the ground and can flash back from a distant ignition source. Tanks exposed to fire can fail violently (a boiling liquid expanding vapor explosion, or BLEVE). The New Jersey Department of Health cites evacuating 1 mile (1,600 meters) when a tank is involved in fire. Firefighters should wear SCBA and full protective gear.

• OSHA Hazard Communication (29 CFR 1910.1200): Hazardous chemical. Labels and safety data sheets are required.
• OSHA Air Contaminants (29 CFR 1910.1000, Table Z-1): PEL 1000 ppm (1800 mg/m³) TWA.
• OSHA LP-Gas standard (29 CFR 1910.110): Rules for storage and handling of liquefied petroleum gases.
• EPA: Not listed as a CERCLA hazardous substance (40 CFR 302.4), an EPCRA extremely hazardous substance (40 CFR 355), or a TRI chemical.
• Clean Air Act 112(r) (40 CFR 68.130): Regulated flammable substance; threshold quantity 10,000 lb. Propane held as fuel for on-site use or sold at retail as fuel is exempt.
• DOT (49 CFR 172.101): UN1978 Propane, Division 2.1; LP-gas mixtures ship as UN1075.

• NIOSH Pocket Guide: Propane
• OSHA Occupational Chemical Database: Propane
• NOAA CAMEO Chemicals: Propane
• NJ Department of Health Hazardous Substance Fact Sheet: Liquefied Petroleum Gas
• BASF SDS: Propane