Does propane go bad?

Figures checked Nov. 10, 2026

We found no official source that gives propane itself a shelf life or expiry date. The time limit in the official rules is on the cylinder. Utah's State Fire Marshal: All DOT cylinders must be recertified 12 years after manufacture date and every 5 years there after. Ask your supplier to check the date stamp. A cylinder that is out of date must not be refilled until it is requalified.

Question	What the official sources say
Does the propane expire?	We found no official expiry date for propane itself
Do DOT cylinders expire?	No expiry date as such, but they must be requalified by the date stamp
Overfilling prevention device (OPD)	required; cylinders without an OPD cannot be refilled

Does propane go bad?

The official pages we checked set no time limit on propane as a fuel. They do set one on the cylinder that holds it.

If you've had a cylinder stored for a long time, the question to ask is whether it is still in date. Ask your propane supplier to check the date stamp.

Do propane tanks expire?

Portable cylinders built to US Department of Transportation (DOT) rules have no expiry date as such, but they must be requalified, counted from the date stamped on them. Utah's State Fire Marshal puts it this way: All DOT cylinders must be recertified 12 years after manufacture date and every 5 years there after. Ask your supplier to check the date stamp.

North Carolina's Department of Agriculture says the same in its consumer guide: a cylinder may be filled for a set period after its manufacturing date, and requalification then extends its life.

Utah's State Fire Marshal also says cylinders that are out of qualification must not be refilled. So if a refill is refused, the date stamp is the first thing to ask about.

How to read the date stamp

North Carolina's Department of Agriculture says each cylinder has a manufacturing date stamped into the collar.

Stamp layouts vary, and we don't hold an official guide to every one. Ask your propane supplier to check the date stamp for you when you refill.

What is an OPD?

An overfilling prevention device (OPD) does what its name says: it helps stop a cylinder being overfilled. For small cylinders, from four to forty pounds, an OPD is required; cylinders without an OPD cannot be refilled.

The rule comes from a national fire code written by the National Fire Protection Association (NFPA), which many states have adopted as state law. The federal hazardous materials rules don't require it, according to the US Department of Transportation's pipeline and hazardous materials office (PHMSA).

What about big home tanks?

The cylinder requalification rule above is for DOT cylinders. For a big tank that a propane company fills in place, ask your propane supplier how it is inspected and how long it can stay in service.

How long does propane last once you're using it?

That's a different question: how long a tank runs your appliances. The propane run time calculator works it out from your tank and your appliance's Btu rating.

Questions people ask

Does propane expire?

We found no official expiry date for propane itself. The time limit in the official rules is on the cylinder.

How long are propane tanks good for?

Utah's State Fire Marshal: All DOT cylinders must be recertified 12 years after manufacture date and every 5 years there after. Ask your supplier to check the date stamp.

Can I refill an old propane tank?

Not if it is out of qualification, or if a small cylinder has no OPD. Ask your propane supplier to check the date stamp and the valve.

Where is the date on a propane tank?

The manufacturing date is stamped into the collar. Ask your supplier to check it.

Before you light it

Carbon monoxide (CO) can kill. US Consumer Product Safety Commission (Official): “Fuel-burning heating systems, including furnaces and fireplaces, can produce CO, an odorless, colorless and deadly gas.” Source(opens in a new tab)
Fit CO alarms and test them. US Consumer Product Safety Commission (Official): “CO alarms should be placed on every level of the home and outside sleeping areas.” “Test the alarms every month to make sure they are working.” Source(opens in a new tab)
Have appliances checked every year. US Centers for Disease Control and Prevention (Official): “Have your heating system, water heater and any other gas, oil, or coal burning appliances serviced by a qualified technician every year.” Source(opens in a new tab)
Chimneys and vents too. US Fire Administration (Official): “Have chimneys and vents cleaned and inspected at least once a year.” Source(opens in a new tab)
If a CO alarm sounds (US: call 911): US Centers for Disease Control and Prevention (Official): “If the detector sounds leave your home immediately and call 911.” Source(opens in a new tab)
Know the signs. US Centers for Disease Control and Prevention (Official): “The most common symptoms of CO poisoning are headache, dizziness, weakness, nausea, vomiting, chest pain, and confusion.” Source(opens in a new tab)
Carbon monoxide (CO). CPSC (Official): "Fuel-burning heating systems, including furnaces and fireplaces, can produce CO, an odorless, colorless and deadly gas." "CO alarms should be placed on every level of the home and outside sleeping areas." Source(opens in a new tab)
If you smell gas (US: call 911). Connecticut Public Utilities Regulatory Authority (Official): "If the smell is strong or you are unsure, leave the building and then call." "Go to a phone that is not near the smell and call your propane company right away." "Don't smoke or strike any matches." "Don't flip light switches on or off." "Put out all open flames." "Call your propane company or 911 for help." This is general advice from one state's regulator: follow your own propane supplier's emergency instructions too. Source(opens in a new tab)
Keep propane cylinders outdoors. Utah State Fire Marshal (Official): "Never store a cylinder inside a house, building, or a garage." Source(opens in a new tab)
Outdoor-only heaters, grills and stoves stay outdoors. Mississippi State University Extension (Official), on outdoor-use-only heaters: "Never use them inside, even temporarily." Source(opens in a new tab)

Sources for this page

2 figures, each with its source

Every figure on this page, with its source. Open one to see the exact words on the source page and how it was checked.

DOT propane cylinder requalification: first due 12 years after the manufacture date, then every 5 years (date stamped on the collar; ask your supplier to check it) Official
From Utah State Fire Marshal: LP-Gas Basic Filling Procedures, which says: “All DOT cylinders must be recertified 12 years after manufacture date and every 5 years there after.” Open the source (opens in a new tab)
Checked Nov. 10, 2026. A blind check looked it up again on Nov. 10, 2026 without seeing our figure: it found that our figure or its wording needed correcting, and the corrected version is the one shown.
Overfilling prevention device (OPD) on 4-40 lb cylinders: required; cylinders without an OPD cannot be refilled Official
From Utah State Fire Marshal: LP-Gas Basic Filling Procedures, which says: “As of April 1, 2002, cylinders without an OPD cannot be refilled!” Open the source (opens in a new tab)
Checked Nov. 10, 2026. A second check re-opened the source page and matched it on Nov. 9, 2026. A blind check looked it up again on Nov. 10, 2026 without seeing our figure: the two agreed.