Source: ACE Hardware.
I’m not the sort of person to buy something new, when the old one still works. But my deep dive into lawn mowers and air pollution has convinced me to buy a new gas can, shown above.
There was nothing wrong with my current gas can. In the sense that it worked exactly as it did when I bought it about three decades ago.
But technology that was fine three decades ago doesn’t really cut it in the modern world.
In this post, I’m going to explain why I took this momentous step.
It’s no secret that gasoline vapors cause smog.
If you are old enough, you may recall the days when automobiles had carburetors. And those carb bowls (internal fuel reservoirs) were vented directly into the atmosphere. So that, in the summertime, parking lots reeked of gasoline, as the fuel in those hot carb bowls rapidly evaporated into the surrounding air.
It was just the way things worked. Nobody questioned it.
One of the very first pollution control measures mandated for cars was the vapor recovery system. Carb bowls had to be vented to a charcoal-filled canister, which held the gasoline vapors until the engine ran and drew them back into the engine air intake.
Eventually, those early vapor-recovery systems morphed into the fully-sealed fuel systems found on all modern cars. In a modern car, no part of your fuel system vents directly into the atmosphere.
Except when you fill the tank, at which time the fresh gasoline displaces your tank full of gasoline vapors, and you dump gallons of gasoline vapor into the atmosphere. This is why gas stations in CARB-compliant areas (such as the DC area) have vapor-recovery nozzles. Those nozzles effectively turn the entire gasoline-delivery system into a closed system. The vapors from your tank are returned to the underground gas storage tanks. The vapors from those underground tanks are returned to the tanker trucks that fill them. And so on.
For cars — at least in high-air-pollution areas that adhere to the CARB standards — the problem with gasoline vapors and photochemical smog has been pretty much taken car of. First by fully sealing the car’s fuel system, and then by recovering vapors all along the refueling supply chain.
Guilty as charged
Contrast the carefully-closed fuel system for cars with your typical lawn mower refueling setup, and you can probably see where this is heading.
According to the California Air Resources Board, gasoline vapors associated with gas cans and refueling a lawn mower produce about about as much smog-forming pollution as running the lawn mower itself. (I’ll add a reference here when I can find it again).
Or, restated, your crappy old gas can creates as much smog-forming air pollution as your gas lawn mower.
Per the California Air Resources Board, gas cans contribute smog-forming emissions in at least five ways:
- Evaporation and spillage during transportation and storage.
- Spillage and/or over-filling as fuel is being dispensed.
- Permeation of vapors through walls of plastic containers.
- Spillage and evaporation through secondary vent holes.
- Vapors escaping while fuel is being dispensed.
But but but … But I don’t spill that much gas. Do I?
You will read that Americans spill 17 million gallons of gasoline each year, refueling small engines. Turns out, that comes from a 1991 study, and it’s based on an estimated average of 15 grams of spilled fuel per refueling event. Which, because there’s no telling how many refills per gas-can-full, the EPA and others tend to use in the form of 15 grams per gas-can-full-of-gas.
Well, 15 grams of gasoline is just over one tablespoon. Between a drip here and there, the occasional major screw up, and the awkwardness of pouring from a full gas can, plus having the spout of the can stored inside — where it is always wet with gasoline — yeah, that’s not unreasonable to think that over the course of using the contents of a two-gallon gas can, I might release a tablespoon of liquid gasoline.
So, spillage? Yeah, guilty as charged. Probably. Not like I’ve ever measured it, but it’s definitely plausible.
Vapors escaping as fuel is dispensed? Guilt again. My crappy old Blitz gas can has no vapor-recovery. Every two-gallon can of gas releases two gallons of gasoline vapors, as it displaces the vapors in the lawn mower fuel tank.
Secondary vent holes? Yep. I’m using an old, pre-CARB can than has a vent with a little plastic cap. No way that’s stopping vapors from escaping.
Permeable plastic? That was a new one on me, but now that I look at modern gas can designs, it’s a pretty good bet that I’m guilty on that front as well. The new ones are laminates of various types of plastic, specifically designed to prevent gas from permeating. My old one is surely a blow-molded one-piece one-material design.
In short, my old Blitz plastic vented gas can is pretty much the poster child for what not to use. Easy to spill when full. Nothing to prevent over-filling. Guaranteed to lose some liquid gas with every filling, due to the spout being stored inside the can. Vented. Probably gas-permeable plastic. No attempt at vapor recovery.
But all gas cans suck
It’s not like I haven’t looked into and purchased alternatives in the past. I own a striking array of types and sizes of gas and kerosene containers. Everything from CARB-compliant vent-through-the-spring-loaded spout, to classic metal NATO jerrycans.
Absolutely none of them was worth a damn for use with a lawn mower. Too big, too easy to spill, awkward venting mechanism, spout still stored inside the can (in the liquid gasoline). And so on.
But you can find anti-new-gas-can rants anywhere.
I need not elaborate except to say that I didn’t actually like my pre-CARB Blitz gas can, either. In particular, storing the spout inside the can — in the liquid gasoline — might have been expedient, but it sure was a mess to use. So, in my opinion, it’s not like CARB ruined a perfect product. It’s more that the early implementation of CARB-compliant (non-vented) cans was definitely a step backward from an already unsatisfactory product.
Except sometimes
In any case, the no-spill can above ticks all the boxes for me. Non-permeable plastic. Spout stored outside of the can, not in the liquid gasoline. Push-button operation to dispense, so no spilling gas when the can is full. Vented through the dispensing nozzle, so it (in theory) recovers the gasoline vapors in the lawn mower gas tank.
In short, this new can addresses the five evils highlighted by CARB.
Even if I don’t give up on my gas-powered lawn mower, this seems like the least I can do. In theory — assuming CARB is right about old-style gas cans — this modest expenditure cuts my emissions of smog-forming chemicals roughly in half. That’s a start.
Extras for experts
Looking around the internet, I see a common estimate that one gallon of gasoline will create roughly 160 gallons of saturated gasoline vapor, at at temperature of 60 F.
Using that estimate, my 15 grams of spilled gasoline per container will generate almost one gallon of gasoline vapor. So spills are second to displaced vapors in terms of gas vapors emitted by lawn-mower refueling. That’s also what CARB’s analysis shows.
But the fact that floored me is that older plastic gas cans are somewhat permeable to gasoline. They apparently off-gas vapors all the time, right through the plastic.
In the spirit of science — and to prove to myself this is an issue — I weighed my old Blitz two-gallon vented plastic can, complete with maybe half a gallon of gas in it. Today (3/31/2023) it weighs 1874 grams. I’ll re-weigh it in a week or so, and report back how much gasoline it appears to lose in a week of sitting in a cold garage.
Edit:
- 3/31 … 1874 grams
- 4/1 … 1872 grams
- 4/2 …. 1868.5 grams
OK, I’m cutting this one short, for benefit of the environment. The can seems to be losing gasoline at a reasonably steady rate. In two days, my old gas can lost 5.5 grams of gas. That’s during cool weather, inside a garage, only partly filled. All of which is favorable to low losses.
So let me call that a minimum year-round loss of 3 grams a day. Doesn’t sound like much, does it? But over the course of a year, that piles up to be about 49 fluid ounces — roughly a quart and a half. Which, because gas vapor occupies about 160 times the volume of liquid gasoline, works out to be 61 gallons of gasoline vapor per year.
Far worse than a typical modern car, including average spillage when filling that car.
I now understand why one of the very first things the California Air Resources Board did was to go after gas cans. Before this, I figured the CARB went after gas cans because …. well, California. But gasoline vapors contribute significantly to smog, which is a big problem in California. And old-style permeable vented plastic cans can emit a mind-boggling quantity of gasoline vapor over the course of the year.
So I’m terminating this experiment and emptying the remaining gasoline into my new (non-vented, non-permeable) can. Then I’ll try to figure out some new use for that old, practically-indestructible gas can. One that does not involve volatile organic compounds.
The nose knows, or a simple at-home test.
Perhaps you, like me, are skeptical of the idea that anyone would have sold gas cans made out of plastic that was permeable to gasoline.
So, as I wait to weigh a week’s worth of gasoline loss, I decided to do the obvious thing. Something I would never have thought needed to be done. But which, in hindsight, is obvious.
I held the gas can up to my nose and took a sniff.
Yep, definitely gasoline permeable. The bottom of the container — where there is liquid gasoline in contact with the plastic — absolutely reeks of gasoline. The portion of the container above the liquid gas, not so much.
So if you remain skeptical of the idea that old plastic gas cans might be bad for the environment, I suggest you give yours a sniff. I haven’t quantified the typical weekly loss yet, but my nose tells me there’s going to be some.
