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How to Properly Store Flammable Fuel

In times emergency, extra fuel on-hand comes in handy to power emergency generators, chain saw and other equipment.

The purpose of this post is to explain all facets of flammable and combustible liquids and how to properly store them for future use.

Color Coded Fuel Cans

In US,. each type of fuel corresponds to its own gas can color. The container should be UL approved or stamped with ASTM (American Society of Testing and Materials).

Please note that US gasoline stations will not allow you to pump fuel into a non-compliant color coded fuel containers (i.e. pump gasoline into a yellow diesel container).

  • Black – non-standard (meaning it has no specific use)
  • Blue – kerosene (or jet fuel in military)
  • Yellow – diesel
  • Green – oils or non-potable water (military use only)*
  • Red – gasoline
  • White (opaque) – drinking water

Also referred to as NATO military gas can, these green “jerry cans” are sometimes found at online retailers sold as gasoline tanks. Most US gasoline retailers will NOT allow you to pump gasoline into these containers.

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Differences Between Flammable and Combustible Liquids

The two primary hazards associated with flammable and combustible liquids are explosion and fire.

Flammable liquids are very volatile due to their ability to produce vapors which when mixed with air, burns quickly when ignited.

While there is a technical distinction between flammable and combustible liquids, they both burn readily .

In US, flammable and combustible liquids are primarily regulated at the federal level by Occupational Safety and Health Administration (OSHA) under 29 CFR 1910.106 (general industry) and 29 CFR 1926.152 (construction)

In addition, the National Fire Protection Association (NFPA) sets consensus and hazard classifications for flammable and combustible liquids under NFPA 30 – Flammable and Combustible Liquids guideline which are generally enforceable under OSHA and many US state and local regulations

United Nation adopted “The Globally Harmonized System of Classification and Labelling of Chemicals (GHS) in 2003 (for more info, click Wiki link here).

The United States was an active participant in the development of the GHS.

In 2009, OSHA published a proposed rulemaking to align OSHA’s Hazard Communication Standard (HCS) with the GHS. For more information from OSHA, click here

NFPA Definition of flammable and combustible liquids

  • A flammable liquid is defined by NFPA as a liquid with flash point that does not exceed 100 F (or 37.8 C) when tested by Pensky Martens closed-cup test method (i.e. meaning it can easily be ignited in air at ambient temperature). Gasoline falls into this category.
  • A combustible liquid is defined by NFPA as a liquid whose flash point is 100 F (37.8 C) or higher when tested by the same closed-cup test method. Diesel falls into this category.

OSHA Definition of flammable and combustible liquids

  • Unlike NFPA ratings, OSHA defines a flammable liquid as any liquid having a flashpoint at or below 199.4 F (93 C).

Hazard Classifications

National Fire Protection Association (NFPA) hazard classifications for flammable and combustible liquids are listed below:

Flammable Liquid Hazard Classifications

ClassFlash pointBoiling pointExamples
I-Abelow 73°F (23°C)below 100°F (38°C)diethyl ether, pentane, ligroin, petroleum ether, gasoline
I-Bbelow 73°F (23°C)at or above 100°F (38°C)acetone, benzene, cyclohexane, ethanol
I-C73-100°F (24-38°C)—-p-xylene

Combustible Liquid Hazard Classifications

ClassFlash pointBoiling pointExamples
II101-140°F (39-60°C)—-diesel fuel, motor oil, kerosene, cleaning solvents
III-A141-199°F (61-93°C)—-paints (oil base), linseed oil, mineral oil
III-B200°F (93°C) or above—-paints (oil base), neatsfoot oil

Plastic vs. Metal Fuel Cans

For home use, the decision to use plastic vs metal fuel can is usually made for you because when you realize you need them, your only choice will be plastic (if you can find one).

If you want a metal fuel can, you will need to plan ahead and buy them in advance of any perceived emergencies.

Generally speaking, if you live in a hot climate year-round, you will want to consider buying a metal can as fuel vapor expansion will be be very hard on plastic containers.

If you live in a more temperate climate, a plastic fuel can will suffice.

Metal Fuel Cans


  • Very durable, does not warp
  • Old metal cans can be recycled
  • Less likely to leak


  • Expensive
  • Can dent easily
  • Can rust

Plastic Fuel Cans


  • Lightweight
  • Cheaper than metal cans
  • Corrosion resistant


  • Will expand in heat (sometimes it looks like a tightly filled balloon)
  • Will contract in cold (plastic can will be crushed, though will bounce back)

Fuel Can Classifications

  • Type I Safety Cans – Accepted under CARD, meeting OSHA and NFPA requirements, UL, ULC, and FM approved for safe handling and storage of gasoline and other flammable liquids
  • Type II Safety Cans – Constructed from galvanized steel (i.e. coated with zinc) and help reduce explosion risks while dispensing flammable liquids; also features flame arresters in the filer opening and spout
  • DOT approved – Type II DOT safe cans come with heavy-duty safety cage around spout to prevent damage during transport

Gasoline Color Indicator

  • Green/blue tint – regular grade (87 octane)
  • Yellow tint – mid grade (89 octane)
  • Pink tint – premium grade (92 octane)

Long term Fuel Storage


  • Technically, there is no expiration date on diesel but the overall performance is affected the longer it is stored
  • Diesel fuel will stay “fresh” for approximately 6 to 12 months under the best condition (stored in a dry, cool environment)
  • If you treat it with a fuel stabilizer (add approximately 1 ounce of stabilizer for every 5 gallons), it will stay “fresh” for up to additional 12 months
  • It is not unheard of using diesel fuel that is over 5 years old!

How can I tell if diesel is bad?

  • Dark orange color
  • Obvious sign of sludge
  • High sedimentary count

Fuel Storage Location

It is not recommended to store extra fuel in your attached garages for obvious safety reasons.

If at all possible, store all highly flammable liquid in an UL-1275 approved storage cabinet.

Furthermore, the location should be cool, dry, well-ventilated and free of sources of ignition.

I store my fuel cans in my shed with ample air circulation.

Two Best Fuel Cans and replacement parts to buy in 2022

There are plenty of exhaustive reviews and recommendations on the internet.

To make it brief, I recommend either of these gas cans for home use.

Both products have been around forever so they are of good quality.

Just keep in mind that they both suck when it comes to filling your outdoor equipment so plan on purchasing a medium and large plastic funnels to keep the refilling time short.

If your old plastic cans have worn out parts (i.e. broken gas caps, etc.), you may want to buy this kit containing 3 sets of replacement funnels and caps

Frequently Asked Questions

  • What does it mean when someone says fuel’s flashpoint?
    • It means the lowest temperature needed to evaporate enough fluid to form a combustible concentration of vapor
  • What is the flashpoint of gasoline?
    • It depends on the composition of gasoline and other conditions, but in general, gasoline’s flashpoint is approximately -45 F
  • Does a lit cigarette ignite gasoline?
    • No, the gasoline vapor, not the liquid, ignite
  • What is the difference between clear and dyed diesel fuel?
    • Diesel used by US government vehicles is dyed blue instead of red to ensure that it is not misappropriated (stolen/sold). There is no performance difference between the two dyed diesel fuel.