I have a red (approved) plastic gas container in the garage. It's not been excessively hot but I went to put gas in my mower for the first time this season and noticed that the thing is swollen and pressurized.
It's some new design that I can't even figure out how to vent. I assumed these all had a slight controlled vent to them but this one apparently does not (was just purchased last summer).

Obviously it would be a bad idea to open that thing because it's pressurized.
But I have no idea of what to do with it. Seems kind of hazardous to keep in my garage at this point. It's not been stored near anything in particular... no source of heat or cold. It's a garage so it stays above freezing all year and rather cool in the summer.

It's a crazy design to the spout system... it has a series of clips at the bottom near the spout, a clip halfway up. I can design websites, I can rebuild a small engine but I cannot for the life of me figure out how this is supposed to work.

My main question remains... what should I do with this pressurized plastic gasoline storage tank. There may be a gallon in there at most. If I open it up, seems like it will spray everywhere which I know is not only dangerous but stupid. Is there ANY way I can open this thing up safely and if not, how does one dispose of a pressurized gas tank?
I can't just leave it in the garage forever.
Thanks in advance for any insight or suggestions.

Drive it to a gas station, or at least call one to ask?

OK, it was either filled too much. Liquid gas tends to expand when heated. Cooling it with a couple of bags of ice comes to mind, but I wouldn't use the cubes aferwards.

Actually, it probably would be fairly safe to open it under the right conditions. Outside with a containment pan under it. An Aluminum roaster pan might be ideal.

I'd wear safety glasses or a face shield and put a clear bag over the can and tape it in a few places to the can. Wear nitrile gloves (Drug or hardware store). Open it under the clear plastic bag. The bag is there so it won't spray. It shouldn't anyway because the release will be under the cap.

It really shouldn't be any different than opening your gas gap on your car when sometimes you hear a whosh.

It's not going to explode on you.

The only hazzard would be that it burst in the garage.

I agree with KISS.

Open cap very little. This will release pressure slowly.

Good luck

Chuck

Yep go with KISS just to be safe but no exploding issues here just open up slowly and make sure your outdoors away from heat ,flame, etc.

Does anyone feel like doing the calulations:

Thermal Expansion

Use a delta T of say 55 F to 85F (convert to C) 55F is ground temp.

Use expansion coef of gasoline.

Get the volume of 1 gal tank. Use 1 gal and 1 cc/ml.

See what the change is in CC's based on the temperature range.

I'd take a pic of the tank and then try to contact approval agencies and manufacturer.

Don't fill any vessel containing gasoline to the top. Check for a fill line of the actual container.

If I did those calculations for that extremely large temperature range, the volume of liquid gasoline would increase by 1/5 of it's initial volume. A fair bit (2 soda cans).

The air pressure would increase to about 3 PSI. Not much to worry about.

I'll bet if you look closely, there may be a fill line on the can. That may have been ignored.

Thanks for all the well thought out answers, ladies and gentlemen.
They are very much appreciated. I checked the fill line vs. the amount in the container.
It's a 1.25 gallon container and the actual amount of gas is about 1/10th of that.
It comes up about 1.25 inches of an approximately 11 inch high container.

So it wasn't overfilled. And the temperature in my garage right now is running at about 58 degrees and probably hasn't run above 68 (fairly mild spring and in a shaded area).

I'm a little confused simply because of the amount it's expanded. I'm fairly cautious regarding things like this (in terms of storage and care of gasoline on my property) and that's why I wanted to ask.

I took necessary precautions and opened the valve as little as possible (having it bagged and wearing facial protection) and it did hiss for about 20 seconds with just a little spewing so I'm good to go. To be honest, I think it's a faulty design... there were very few variables left since it wasn't even close to being up to the max fill line and the temperatures have been fairly mild. It's not a climate controlled garage but it never dips below 40 and rarely gets over 80 even in the heat of summer.

The plastic seems really flimsy... I picked it up at Wal Mart against my better judgement in a pinch thinking they're all the same. Obviously approved but under what circumstances I guess is the question.

Thanks again for the thoughtful, well written replies. It's nice to know that in this day and age people are willing to offer others advice when they need it.
I will do my best to enter the other areas and spread some of my knowledge around to help repay. I can assure you that home improvement and yards are not my area of specialization but sometimes I wish it were.

I'll have to look at the problem in terms of the air in the tank. I think the flimsyness of the tank is the real problem.

I have 2 gas cans, One a metal one that's easily 40 years old and a hard plastic one that holds an Imperial Gallon, The latter is for the 2 cycle engines. The cans are sufficiently different that it's very difficult to confuse.

Neither can has any vents.

I think I'd throw the one you have away and look for a sturdier can.