# Should I Turn Off the Engine While Pumping Gas? **URL:** \ **Category:** Factual Questions\ **Created:** [June 1, 2004, 4:13pm UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089 "2004-06-01T16:13:34Z")\ **Posts on this page:** 20\ **Page:** 3
**Author:** ![tadc](https://avatars.discourse-cdn.com/v4/letter/t/f07891/32.png) [@tadc](https://boards.straightdope.com/u/tadc)\ **Post date:** [June 3, 2004, 12:05am UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089/41 "2004-06-03T00:05:30Z")
> [@kanicbird](#): > > Actually it happened inthe Albany NY area about 2 weeks ago (you find the cite!!!), it was reported in the news, the fire dept members were actually taken back that a cell phone could actually cause a fire/explosion. I assume you mean this: [http://msnbc.msn.com/id/4979598/](http://msnbc.msn.com/id/4979598/) Who/what says it “apparently” was the cell phone? Certainly it was a static discharge, just like all the other documented cases. A cell phone just doesn’t put out enough energy for that. The article says the fire started when his phone rang, and then seems to assume that must be the cause. One thread I read on Telecom-Digest a few months back about this indicated that at least one big oil company was campaigning against cell phone useage at the pumps, not because it causes fire, but because it interferes with their wireless pay-at-pump system. > [@](#): > > Anyway I feel that if your car is going to have some trouble it will more likely happen if you are going to start the car then keep it running. I would rather get to my destination then be unable to start the car at a gas station. So you are saying you’re car is a POS and you leave it running at the pump because you’re afraid it won’t start again?? 😕 Better hope that at least your ignition system is in good shape. ---
**Author:** ![yastobaal](https://avatars.discourse-cdn.com/v4/letter/y/258eb7/32.png) [@yastobaal](https://boards.straightdope.com/u/yastobaal)\ **Post date:** [June 20, 2004, 4:31pm UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089/42 "2004-06-20T16:31:37Z")
> [@qts](#): > > It has most definitely happened: it was caught live on TV. I forget who the driver was but it was a Formula 1 Grand Prix, the guy pumping the fuel didn’t close the valve quickly enough, and the fuel ignited and flashed over the car. taken from [some web site](http://www.totalf1.com/weekly-wrap/?columnid=36) > [@](#): > > delivery seemed normal until the flow ceased and the pit crew tried to pull out the hose from the nozzle. Something went wrong, and fuel leaked onto the hot surface of the car, igniting and causing a dramatic pit fire that covered the right side of the Ferrari! Having trained the procedure many times the crew immediately extinguished the flames and Schumi kept cool, yet his stop also reached twenty seconds and Räikkönen and Montoya got through comfortably to take first and second spots. ---
**Author:** ![jsleek](https://avatars.discourse-cdn.com/v4/letter/j/8dc957/32.png) [@jsleek](https://boards.straightdope.com/u/jsleek)\ **Post date:** [June 20, 2004, 9:36pm UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089/43 "2004-06-20T21:36:42Z")
- it’s happened to me twice, and gas gushes out of the already-full tank onto the ground. - me too. Poured a lot of gas on the ground, but nothing happened. Actually, I don’t think there’s enough of a fire danger to be all worried. Gas fumes are way more dangerous iinside. I’ve always filled my tank while outside. I figure there’s a lot more risk of the car dropping into gear, or the parking brake not being on right, or someone knocking the shift lever, or one of many reasons that the car might drive away. The actual hazard is not being in control of your car while it’s running. It’s a lazy, sloppy, inconsiderate thing to do; similar to playing your stinking rap music while filling your tank. ---
**Author:** ![ZipperJJ](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zipperjj/32/211_2.png) [@ZipperJJ](https://boards.straightdope.com/u/ZipperJJ)\ **Post date:** [June 20, 2004, 10:46pm UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089/44 "2004-06-20T22:46:18Z")
> [@anson2995](#): > > But nobody has answered the OP’s question, which was whether this “theoretical danger” was in fact hogwash. I think the failure to produce a single citation of an explosion being caused by an engine running during fueling is pretty telling. In the absence of any other evidence, I’m inclined to conclude that it has never happened. If that’s true, then I would further suggest that the theoretical danger is based on a misunderstanding of the science involved. Yeah but doesn’t the “fact” that a good number of us posters have never heard of or seen anyone leave their engine on while pumping gas seem to suggest that the sample from which we can draw these conclusions would be quite small? If EVERYONE left their cars running while refueling, I’d bet we’d see some fires resulting each year. But since it seems that not many people do it…we’ll never know. In general, we’re good at reading the signs that tell us not to leave the engine running 😉 Unless, that is, someone asks MythBusters 🙂 ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [June 20, 2004, 11:06pm UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089/45 "2004-06-20T23:06:24Z")
My thoughts on it is that the most chance of maulfunction of the car will happen while trying to start it as opposed to idling it, and if I am going to get stranded, I’d rather be at my destination (hopefully home) then at a intermediate stop (gas station). ---
**Author:** ![EllisDee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ellisdee/32/4531_2.png) [@EllisDee](https://boards.straightdope.com/u/EllisDee)\ **Post date:** [June 21, 2004, 4:55am UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089/46 "2004-06-21T04:55:12Z")
> [@Cerowyn](#): > > Do you really believe that there’s no common sense reason to turn off an **internal** combustion engine […] while pumping volitile fuel into your tank? (Emphasis added) Common sense reason? No. There would only be a common sense reason if it were an external combustion engine. Please explain how my spark plugs – which are all the way in the front of the car – are a danger while I am fueling in the back of my car. Now explain how the guy who pulls up to the pump behind me – leaving his front bumper 2 feet from my back bumper, which brings _his_ spark plugs much closer to my nozzle – was not more of a danger during the action of pulling in, when his car was, of course, running. This question has been repeatedly asked in this thread by numerous posters. The only replies have been, essentially, hand-waving. Factual answers indeed. Here’s my point: the dreaded spark plug danger has been tested every time any other car has been in line with you at the pump. That is almost as much of a sample as if half the population habitually left the engine running while pumping gas. Give me a solid reason. Someone mentioned that parts of a car are really hot while running. That’s at least a common sense approach. At least it is in my world where the car magically cools to room temperature the moment I turn it off. :rolleyes: ---
**Author:** ![Dr.Lao](https://avatars.discourse-cdn.com/v4/letter/d/2bfe46/32.png) [@Dr.Lao](https://boards.straightdope.com/u/Dr.Lao)\ **Post date:** [June 22, 2004, 1:53am UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089/47 "2004-06-22T01:53:15Z")
> [@Ellis Dee](#): > > Common sense reason? No. There would only be a common sense reason if it were an external combustion engine. The heat has to go somewhere. And bunches of it goes out the tailpipe. As 1300 F gas. > [@](#): > > Please explain how my spark plugs – which are all the way in the front of the car – are a danger while I am fueling in the back of my car. Now explain how the guy who pulls up to the pump behind me – leaving his front bumper 2 feet from my back bumper, which brings _his_ spark plugs much closer to my nozzle – was not more of a danger during the action of pulling in, when his car was, of course, running. The sparkplugs ain’t the problem. The amount of fuel and air exposed to the spark is tightly controlled by the car’s fuel system. ---
**Author:** ![obfusciatrist](https://avatars.discourse-cdn.com/v4/letter/o/4af34b/32.png) [@obfusciatrist](https://boards.straightdope.com/u/obfusciatrist)\ **Post date:** [June 22, 2004, 2:02am UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089/48 "2004-06-22T02:02:18Z")
My car won’t start if the gas tank flap is open (2003 Civic Hybrid). I don’t know if it will open if the car is running. The only way to open it is with a button inside the car. I’ll have to try it. ---
**Author:** ![tadc](https://avatars.discourse-cdn.com/v4/letter/t/f07891/32.png) [@tadc](https://boards.straightdope.com/u/tadc)\ **Post date:** [June 22, 2004, 5:35am UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089/49 "2004-06-22T05:35:00Z")
> [@Dr. Lao](#): > > The sparkplugs ain’t the problem. The amount of fuel and air exposed to the spark is tightly controlled by the car’s fuel system. **Except** when the (poorly maintained) ignition system is malfunctioning, and/or fuel is spilled or leaking. The low probability of a) Malfunctioning ignition creating a spark(or red-hot exhaust from preceeding street-race), b) in the vicinity of fuel vapors of the correct fuel/air mixure for combustion, c) in a situation where fuel is being actively delivered to the region of combustion all happening at once is the reason we don’t hear about more gas station fires due to leaving the engine running. Mostly the absence of a), because modern cars ignition systems are much safer than their ancient counterparts, and b) because there really is a fairly narrow range of vapor concentration that will allow combustion. If fuel is not being actively delivered, the danger is much less because ignited vapors are likely to go _poof_ and extinguish themselves. We can refer to the static-electricity videos to see what happens when a car being actively fueled ignites and the driver decides it’s a good idea to yank the nozzle out of the tank. :eek: The arguments implying that _other_ cars pulling up/driving away present the same danger as leaving your own car running are wrong. When the car moves, it tends to dissapate any fuel vapors hanging around simply by displacing lots of air. ---
**Author:** ![buttonjockey308](https://avatars.discourse-cdn.com/v4/letter/b/bcef8e/32.png) [@buttonjockey308](https://boards.straightdope.com/u/buttonjockey308)\ **Post date:** [June 22, 2004, 6:33am UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089/50 "2004-06-22T06:33:45Z")
Indeed you should. Here’s why. 1. Hydrocarbon fuel vapors are considerably heavier than air. They escape from the tank as you fill, and seek out ignition sources that may not be present if the car is not running. Sources may be a crack in your spark plug wires that you may not know about, or some other electrical malfunction that exposes bare arcing wires to gasoline fumes. You couldn’t run away fast enough. 2. Keep in mind that your car’s catalytic converter operates at an extremely high temperature (usually about 1,600 degrees) and that the flash point of gasoline is -45 F. If there is something wrong with the converter and the heat shield is missing or it is cracked, this can present an extreme hazard. 3. It’s not only _your_ car you need to worry about. Gas vapors are, as previously stated, heavy. They can travel in excess of 300 feet in favorable conditions, while still remaining at their LEL or lower explosive limit. If someone near you has a vehicle in disrepair, you may still be at risk. All that said… 15 years on the fire dept. and I have never once responded to a call of a fire that was a direct result of leaving the engine running while fueling. Still, I’m not willing to risk the lives of my fellow man, just to save a few nanoseconds turning the key to start my car back up. Shut your car off when getting gas. It just makes sense. ---
**Author:** ![Futile\_Gesture](https://avatars.discourse-cdn.com/v4/letter/f/f05b48/32.png) [@Futile\_Gesture](https://boards.straightdope.com/u/Futile_Gesture)\ **Post date:** [June 22, 2004, 12:11pm UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089/51 "2004-06-22T12:11:07Z")
Oil shortages? We don’t care! Keep that motor running! Pollution? Ha! Our motors are clean! See, the exhaust is like a breeze across a summer meadow! Global Warming? Bah! What’s that compared to the convenience of not having to turn my ignition key! Keep belching that CO2! Quite apart from the safety considerations, you should never pointless leave your engine running when you are out of your vehicle. It’s an obscene waste. Many car manufactures also make it impossible to open your tank while the keys are in the ignition. Do they do this just to be annoying? Or are there good safety, legal and moral reasons for it? ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [June 22, 2004, 1:55pm UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089/52 "2004-06-22T13:55:04Z")
> [@buttonjockey308](#): > > Indeed you should. Here’s why. > 2. Keep in mind that your car’s catalytic converter operates at an extremely high temperature (usually about 1,600 degrees) and that the flash point of gasoline is -45 F. If there is something wrong with the converter and the heat shield is missing or it is cracked, this can present an extreme hazard. Minor nit to pick here. Your quoted temp for a converter is about 1000 degrees high. Converters work at between 540- and about 800 under normal conditions. Under extreme conditions they may get to 1200 or so. Above that and the converter would be damaged beyond repair. At idle in a gas station, the converter will be near the lower end of the temps quoted. However this is still plenty hot enough to light off any gas fumes. ---
**Author:** ![nightstalker52](https://avatars.discourse-cdn.com/v4/letter/n/49beb7/32.png) [@nightstalker52](https://boards.straightdope.com/u/nightstalker52)\ **Post date:** [August 30, 2014, 4:46pm UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089/53 "2014-08-30T16:46:22Z")
in most states, if not all of them it is required to shut off your engine, no smoking or external flames and recently no electronic devices are allowed while refueling your vehicle. as a young boy my dad was a fuel hauler, and I later hauled a fair amount of it. I have heard of cases where fires have been started by accident while fueling a car. but in a refinery where gas vapors are abundant there have been many cases where fires have been started by static electricity. there is a recent video on u-tube where a man working at a refueling depot blew himself and the loading rack up when he apparently answered a cell phone. while the accidents at a station are uncommon, it only takes one to cause a disaster. ---
**Author:** ![susan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/susan/32/17537_2.png) [@susan](https://boards.straightdope.com/u/susan)\ **Post date:** [August 30, 2014, 5:25pm UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089/54 "2014-08-30T17:25:51Z")
Zombie vapors. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [August 30, 2014, 5:58pm UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089/55 "2014-08-30T17:58:43Z")
zombie or no getting a reminder on safe fueling every decade is a good thing. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [August 30, 2014, 6:07pm UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089/56 "2014-08-30T18:07:26Z")
‘Hot refuelling’ (refuelling with the engine running) is fairly common in turbine helicopters. ([AOPA link](http://blog.aopa.org/helicopter/?p=599).) If your car has a turbine engine that is well away from the fuel port, go for it. If you have a piston engine, turn it off. ---
**Author:** ![GusNSpot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gusnspot/32/436_2.png) [@GusNSpot](https://boards.straightdope.com/u/GusNSpot)\ **Post date:** [August 30, 2014, 7:25pm UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089/57 "2014-08-30T19:25:10Z")
> [@nightstalker52](#): > > ::: snip :::: > but in a refinery where gas vapors are abundant there have been many cases where fires have been started by static electricity. there is a recent video on u-tube where a man working at a refueling depot blew himself and the loading rack up when he apparently answered a cell phone. while the accidents at a station are uncommon, it only takes one to cause a disaster. {nitpick}I just watched that & at the very end it said he tried to use the cell phone as light source.{/nitpick} The point being that yes, a cell phone can be a problem. YMMV 😃 ---
**Author:** ![Killing\_Time](https://avatars.discourse-cdn.com/v4/letter/k/76d3ee/32.png) [@Killing\_Time](https://boards.straightdope.com/u/Killing_Time)\ **Post date:** [August 30, 2014, 7:34pm UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089/58 "2014-08-30T19:34:09Z")
> [@aaelghat](#): > > I think having the fuel-filler cap on is just an emissions control issue. When you’re fueling the cap is off anyway. It’s not the act of taking the cap off that triggers the engine code and makes the check engine light come on. It is the act of running the engine with the cap off. And I’m not sure what you mean by it being “just” an emissions issue. You won’t be able to pass a smog check with the check engine light on, and I would imagine a malfunctioning smog system is putting more pollution into the air. If this can be avoided by the simple act of turning off your engine before you pump gas, why would you not do it? ---
**Author:** ![rsat3acr](https://avatars.discourse-cdn.com/v4/letter/r/a3d4f5/32.png) [@rsat3acr](https://boards.straightdope.com/u/rsat3acr)\ **Post date:** [August 30, 2014, 7:40pm UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089/59 "2014-08-30T19:40:46Z")
> [@Johnny\_L.A](#): > > ‘Hot refuelling’ (refuelling with the engine running) is fairly common in turbine helicopters. ([AOPA link](http://blog.aopa.org/helicopter/?p=599).) If your car has a turbine engine that is well away from the fuel port, go for it. If you have a piston engine, turn it off. Yes we did open port hot refuling on Hueys when I was flying in the Army(80-85). ---
**Author:** ![GusNSpot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gusnspot/32/436_2.png) [@GusNSpot](https://boards.straightdope.com/u/GusNSpot)\ **Post date:** [August 30, 2014, 7:42pm UTC](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089/60 "2014-08-30T19:42:47Z")
> [@Johnny\_L.A](#): > > ‘Hot refuelling’ (refuelling with the engine running) is fairly common in turbine helicopters. ([AOPA link](http://blog.aopa.org/helicopter/?p=599).) If your car has a turbine engine that is well away from the fuel port, go for it. If you have a piston engine, turn it off. I disagree somewhat. Aircraft, it is usually static arc between the fueling hose & the area around the fill port. Moving liquid will induce as electrical charge difference between the nozzle and the aircraft. Many military places still use the static cable before opening the filler inlet. I have hot fueled many piston engined aircraft. Just be sure the hose & aircraft are grounded together before opening the cap/plug and then keep the line/nozzle & tank in constant contact until finished. Car gas stations = same procedure + the cell phone + cigarettes + all the other stupid stuff. Don’t forget that you can build quite a charge on your self just sliding out of the seat, even bucket seats, and so you need a hand on the nozzle & touch the nozzle to the car near the fuel tank before opening the cap. People generally do not do all of this so the actual number of fires caused at gas stations in not huge. Seems more danger in driving off with the nozzle still in the tank & yanked off the pump is potentially a bigger danger, IMO. In general, for the lack of care in refueling by the general public, there is not many ka-booms. Still see a lot of grounding wires at even general aviation fields, on tanker deliveries to gas stations & refineries. Just what I have seen, IMO, etc. 🆒 [Previous page](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089.md?page=2) [Next page](https://boards.straightdope.com/t/should-i-turn-off-the-engine-while-pumping-gas/248089.md?page=4)