Mechanics & chemists: Is it safe to store gasolene in a #2 plastic (HDPE) jug?

For reasons too complicated to go into, I need to store a gallon of auto gas for a couple of days. The only container I have is an empty (and thouroughly rinsed and dried) laundry detergent jug. It has a #2 HDPE stamp on the bottom.

Will it work, or will the gas dissolve (or whatever) the plastic?

Will the plastic contaminate (or whatever) the gas?

This is sort of an emergency, not a longterm or regular thing, so please do not scold me for not using a real gas can. Thanks all!

Sorry about the typo.


I once made the mistake of using a washed out milk jug (also #2 HDPE) to mix some two stroke-engine fuel (half gas, half oil). I had just poured in a pint or two of gasoline and went looking for my oil. I couldn’t find the oil, but when I returned 10 minutes later, I found a puddle of gasoline all over the floor and some nasty vapors in the air.

Gasoline will ‘melt’ HDPE. It also melted some 4" pipe I was working with on that job down in Clovis, NM.

Dude, if this was ever the time to resurrect the old SNL skit, “Bad Idea Jeans”, I’d buy you two pair of denims.

Trip, are you sure? Your dire tale sent me scurrying on the web. Here’s what I found.

First, it seems they make real gas cans from HDPE. See here:

Second, I found this from a very credible-looking website:

“…Various types of plastics (e.g. High Density Polyethylene (HDPE), Nylon or Teflon) are extremely resistant to petroleum fuels and their flexibility means a reduction of piping joints. However, this type of piping may not be suitable in certain applications, because plastic does not have the same structural strength as steel…”

(Got it from here: )

Lastly, the gas has already been in my jug overnight and it appears to be doing fine.

So what’s the real straight dope.

Well, all I can offer is that I had a milk jug, which had the same recycling label on it. It melted. Flat out. Maybe it’s a byproduct of that recycling that added something which was soluble with gasoline. Pure HDPE may be resistant to gasoline–although I’m doubting that with the pipe on my recent job. But I do recall cleaning up the mess, and looking on the bottom of the milk jug in the fridge to find out what it was made of thinking, “Holy crap, I’ll never do that again. . .”

So, I retract any credible status you may have thought I had on the issue. I just didn’t want you to end up with a puddle of gasoline on the floor, and flammable fumes flying in the air.

Just lookin’ out for ya, man–based on previous observations/experiences.

A friend and I once bought an old weedwhacker engine for a project - (had it running last month. Sure. If you were on fire at the time!) and had to replace the tank on it. Since we knew gasoline dissolved certiain plastics, we checked on the net and after a long search found a bottle of bubble-blowing liquid with (IIRC) the HDPE stamp on it. It held a combination of gasoline and 2-stroke oil for over a year until we got sick of the damned thing not working and tossed it out.

Chemical resistance chart
HDPE shows little etching by room temperature gas over 30 days, but LDPE is etched within a week. A cheap jug labelled HDPE may have more in properties common with LDPE, than with an HDPE container designed for gasoline storage.

Your HDPE gas can link specifically says “High-molecular-Weight-HDPE polyethylene can.” What’s the molecular weight distribution in a laundry detergent container?
It may hold up for days or weeks, or even months, but do you want to be around if and when it fails?

It is not safe 'cause it’s against the law!!

      • I do not know the specifics of storing gasoline in plastic containters of this type–but one thing I do know is that milkjugs very often have pinhole leaks along their seams. They are manufactured by blowing two halves, and then melting the two halves together–and often, the seam does not seal completely. They way they are used (for storing milk for only a few days) they work because the milk dries and partially seals the hole, but for many other uses the leaks will be a problem…

So is it against the law to reuse a postage stamp, that doesn’t make it unsafe.

Don’t they sell metal gasoline cans at Home Depot/Lowe’s or whatever store may be in your area?

I never liked plastic gas containers.

Why don’t you just put the gas into the nearest car and call it done?

Umm… what is the value of this gasoline? What is the value of the jug? Why not safely dispose of the gasoline and charge the owner later?

The causality of gasoline being unsafe to store in milk jugs and being illegal has been reversed. Apparently gasoline is faster than light.

Sure it’s unsafe, reuse a stamp, and spend the rest of your life in fear of the Postal Gestapo.

Doing anything illegal is unsafe, you just to have balance the risk/benefit ratio.

Laundry Detergent Jugs are usually much thicker walled than milk jugs.
Milk jugs are really unsafe and have an excellent chance of leaking.
The Laundry Detergent Jug should be safe for a day.
I find it much harder to clean out the big Laundry bottles than any other bottles. If it is not clean, you will probably be contaminating the gas.
Try to at least store the jug in a cool place out of the sun.
If possible borrow or buy a real Gas container. Stores like Wal-Marts usually have them very cheap. Under $5.

Is that really so? Aren’t those the same gallon jugs in which you can buy water? Those don’t seem to leak, and I doubt dried water would have the same sealing effects as dried milk :wink: