# "Please turn off cellular phone while pumping gas" **URL:** \ **Category:** Factual Questions\ **Created:** [February 26, 2003, 4:26am UTC](https://boards.straightdope.com/t/please-turn-off-cellular-phone-while-pumping-gas/157563 "2003-02-26T04:26:00Z")\ **Posts on this page:** 12\ **Page:** 2
**Author:** ![GaryM](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garym/32/241_2.png) [@GaryM](https://boards.straightdope.com/u/GaryM)\ **Post date:** [February 26, 2003, 6:45pm UTC](https://boards.straightdope.com/t/please-turn-off-cellular-phone-while-pumping-gas/157563/21 "2003-02-26T18:45:44Z")
> [@](#): > > \*Originally posted by ChordedZither \* > [BCertainly the cell phone is a moderately powerful RF transmitter, but that’s not an obvious source of fire hazard. (Does anyone know if similar restrictions were ever imposed on vehicles with CB radios and other transmitters?) \*\* In the USA, handheld cell phones are limited to .6 watts of power. I’m an amateur radio operator and I, as well as all the others I know, are always certain to be off the air when in or pulling into a gas station. Most of our radios are in the 25 to 75 watt output range, so it’s possible that the RF could cause an induced current of enough magnitude to cause a problem. Better to be safe! Ever notice the signs in some construction zones “Blasting area, turn off two way radios!” ---
**Author:** ![Cyn](https://avatars.discourse-cdn.com/v4/letter/c/a88e4f/32.png) [@Cyn](https://boards.straightdope.com/u/Cyn)\ **Post date:** [February 26, 2003, 6:55pm UTC](https://boards.straightdope.com/t/please-turn-off-cellular-phone-while-pumping-gas/157563/22 "2003-02-26T18:55:42Z")
At the hospital I work at, we ask visitors not to use their cell phones in patient’s rooms that have IV infusion pumps or ventilators running. We don’t want signals from the cells to change the rates of the infusing pumps or to switch any thing off. I don’t know which kinds of phones emit what power of signals, so batter safe than sorry. Most people don’t mind—they like their loved ones getting the thngs they need! ---
**Author:** ![danceswithcats](https://avatars.discourse-cdn.com/v4/letter/d/9e8a1a/32.png) [@danceswithcats](https://boards.straightdope.com/u/danceswithcats)\ **Post date:** [February 26, 2003, 9:29pm UTC](https://boards.straightdope.com/t/please-turn-off-cellular-phone-while-pumping-gas/157563/23 "2003-02-26T21:29:58Z")
> [@](#): > > \*Originally posted by GaryM \* > \*\*I’m an amateur radio operator and I, as well as all the others I know, are always certain to be off the air when in or pulling into a gas station. Most of our radios are in the 25 to 75 watt output range, so it’s possible that the RF could cause an induced current of enough magnitude to cause a problem. Better to be safe! > > Ever notice the signs in some construction zones “Blasting area, turn off two way radios!” \*\* Regarding blasting zones, I believe that refers to the issue of a given length of wire becoming a random fundamental of the transmitting frequency, and as such, gathering sufficient energy to activate an initiating device. Example: Quarter-wave antenna (ordinary wire). Length in feet = 234/frequency in MHz. After installation of a fire alarm system in a local fire station, one particular smoke detector would trip if truck radios transmitted while in the building. It was found that one of the leads attached to this detector head was approximately equal to tht of a quarter-wave antenna for the transmitting frequency. Personally, I’m more concerned about people filling plastic fuel cans sitting on bed liners of pickups than I am about cell phone usage at a gas station, as static is more likely to cause a problem than RF, IMHO. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [February 26, 2003, 10:11pm UTC](https://boards.straightdope.com/t/please-turn-off-cellular-phone-while-pumping-gas/157563/24 "2003-02-26T22:11:25Z")
> [@](#): > > \*Originally posted by zwede \* > \*\*If I single freak spark could blow up a gas station I would think having a car with old spark plug wires would spell certain death. If you look under the hood of a car at night with old plug wires you can see sparks arcing from the wires to the engine block and exhast manifold. These sparks would be much stronger than anything a cellphone could generate. A typical car ignition system produces 12000-50000 volts. > > /Markus \*\* Yes, but that’s hardly something that the stations can easily regulate, whereas cellphones are (regardless of how small a risk they may be in comparison). It’s also not in such close proximity to high concentrations of vapour, such as those spilling out of the tank inlet as you fill it. ---
**Author:** ![aeropl](https://avatars.discourse-cdn.com/v4/letter/a/f05b48/32.png) [@aeropl](https://boards.straightdope.com/u/aeropl)\ **Post date:** [February 26, 2003, 11:21pm UTC](https://boards.straightdope.com/t/please-turn-off-cellular-phone-while-pumping-gas/157563/25 "2003-02-26T23:21:30Z")
Electric motors can create sparks, like the one that vibrates your phone. I think if Cecil wrote a column the conclusion will be that it’s doubtful that any cellphone could case a fire at a gas pump. There’s too many other things to worry about. ---
**Author:** ![Daftbugger](https://avatars.discourse-cdn.com/v4/letter/d/9fc29f/32.png) [@Daftbugger](https://boards.straightdope.com/u/Daftbugger)\ **Post date:** [February 27, 2003, 11:19am UTC](https://boards.straightdope.com/t/please-turn-off-cellular-phone-while-pumping-gas/157563/26 "2003-02-27T11:19:18Z")
I’m agreeing with Witty. I’ve also read that it’s the spark from the battery that can be the problem. You’re also not supposed to use a Walkman or any other battery operated device when filling up. If you drop the phone or whatever, the spark is going to occur very close/on the ground where there may be a puddle of spilled petrol. Engine sparks are a lot higher. ---
**Author:** ![El\_Kabong](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/el_kabong/32/496_2.png) [@El\_Kabong](https://boards.straightdope.com/u/El_Kabong)\ **Post date:** [February 27, 2003, 3:19pm UTC](https://boards.straightdope.com/t/please-turn-off-cellular-phone-while-pumping-gas/157563/27 "2003-02-27T15:19:59Z")
> [@](#): > > In the UK Shell are actually installing cell-phone base transmitters in some of their filling stations with the anntennas hidden in the " Shell " sign. These base stations are much more powerful than the actual cell phone . So if it is safe enough for the base station then it must be safe enough for the cell phone. Speaking of Shell, the oilfield service company I work for uses a Shell safety alert concerning cellphones in our safety training. The alert, originating from Shell Expro UK, and dated February 2002, mentions three incidents where gasoline vapors ignited due to cell phones ringing while their owners were pumping fuel. The incidents (locations and dates were not named) are described as below: > [@](#): > > In the first case, the phone was placed on the boot lid during fuelling, it rang and the ensuing fire destroyed the car and the pump. > In the second, an individual suffered burns to the face when fumes ignited as he answered a call during fuelling. > In the third case, an individual suffered burns to the thigh and groin as fumes ignited when the phone, which was in his pocket, rang during fuelling. According to the alert, it was believed that ignition was caused not by the radio signals, but by the ringer, or by the lighting up of the phones’ displays when the incoming call was received. ---
**Author:** ![Sofa\_King](https://avatars.discourse-cdn.com/v4/letter/s/58956e/32.png) [@Sofa\_King](https://boards.straightdope.com/u/Sofa_King)\ **Post date:** [February 27, 2003, 3:54pm UTC](https://boards.straightdope.com/t/please-turn-off-cellular-phone-while-pumping-gas/157563/28 "2003-02-27T15:54:13Z")
I wonder… not too long ago I heard a public radio segment about the abysmal state of Iraqi telecommunications. There is no reliable cellular network to speak of. Instead, what people do to show off there is somehow tweak up cordless phones so that they can be used up to a mile or two away from the base unit. Unfortunately, I don’t know if the phone itself has to be modified, or just the base unit. Would an overclocked cordless phone perhaps be more dangerous at a gas station than a regular cell phone? Is it possible that these rumors actually originated from someplace like Iraq or Somalia where such practices are common? ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [February 27, 2003, 6:22pm UTC](https://boards.straightdope.com/t/please-turn-off-cellular-phone-while-pumping-gas/157563/29 "2003-02-27T18:22:59Z")
> [@](#): > > \*Originally posted by Sofa King \* > \*\*Would an overclocked cordless phone perhaps be more dangerous at a gas station than a regular cell phone? Is it possible that these rumors actually originated from someplace like Iraq or Somalia where such practices are common? \*\* The “spark” danger supposedly comes from the battery not making good contact (which seems like a load of BS if you ask me). You’d almost have to have a microwave oven level of radio transmitter to make gasoline go up in flames. I doubt that the rumours came from 3rd world countries. I have a hunch that the original warning stickers were placed on gas pumps because the cell phone radiation could make the digital electronics in the early digital pumps go screwy. Then some of the folks who believe cell phones were the root of all evil took the idea of exploding gas pumps and ran with it. Remember that in the early days of cell phones there was some debate over whether they caused cancer and such. With no real evidence either way, those opposed to cell phones tended to latch onto anything that cast them in a negative light. Personally I think that is what made the rumours popular, but that’s just IMHO. ---
**Author:** ![bbeaty](https://avatars.discourse-cdn.com/v4/letter/b/c0e974/32.png) [@bbeaty](https://boards.straightdope.com/u/bbeaty)\ **Post date:** [February 27, 2003, 7:30pm UTC](https://boards.straightdope.com/t/please-turn-off-cellular-phone-while-pumping-gas/157563/30 "2003-02-27T19:30:56Z")
Always remember: the general public operates on the belief that “if many people are afraid of something, then it MUST be dangerous, because this many people could not be wrong.” Thats why so many dire-warning rumors exist. Here’s the opposite viewpoint: “The fact that an opinion has been widely held is no evidence whatever that it is not utterly absurd; indeed in view of the silliness of the majority of mankind, a widespread belief is more likely to be foolish than sensible.” - Bertrand Russell So, how large a spark does it take to cause a gasoline fire? Here’s the best article I’ve been able to find online: Rule of thumb: 200 microjoules ignites flammable vapor [http://www.ce-mag.com/archive/1999/novdec/mrstatic.html](http://www.ce-mag.com/archive/1999/novdec/mrstatic.html) Some less-rumorly warnings: Chevron [http://www.chevron.com/prodserv/fuels/bulletin/product\_safety.shtml](http://www.chevron.com/prodserv/fuels/bulletin/product_safety.shtml) Chevron [http://www.chevron.com/prodserv/fuels/bulletin/gasoline\_safety.shtml](http://www.chevron.com/prodserv/fuels/bulletin/gasoline_safety.shtml) Petroleum Equip. Inst [http://www.pei.org/static/](http://www.pei.org/static/) Petroleum Equip. Inst [http://www.pei.org/FRD/gascan.htm](http://www.pei.org/FRD/gascan.htm) ---
**Author:** ![mipiace](https://avatars.discourse-cdn.com/v4/letter/m/eb9ed0/32.png) [@mipiace](https://boards.straightdope.com/u/mipiace)\ **Post date:** [February 27, 2003, 9:58pm UTC](https://boards.straightdope.com/t/please-turn-off-cellular-phone-while-pumping-gas/157563/31 "2003-02-27T21:58:59Z")
A spark from a cell phone battery is enough to ignite a fire and it doesn’t have anything to do with a puddle of gasoline. If you read on the sign probably also reads something about not filling gas cans unless they are on the ground which also seems like an extreme remote risk of ignition but believe me - it happens. About three months ago at the gas station down the street, some idiot was filling gas cans inside the bed of his truck. It is the fumes that ignite and only takes the spark of static electricity. This guy got back into his truck while the cans were filling (also a no-no) slid out of the seat (causing static to build) did not touch the body of the truck to discharge static prior to fiddling with the gas hose and KABOOM! It started a small fire in the bed of his truck which progressed to the gas hose/gas can. The guy next to him told him to step back but not wanting to burn his nice truck, he threw the gas can behind him which equated to a large maltoff cocktail. So now the truck is on fire, the guy is one fire and there is a very large fire on the ground behind the truck. this could have been a HUGE explosion…fortunately people standing by beat the guy with shirts until they put the fire out on him and the guy in the gas station used a fire extinguisher to put out the truck and the ground. I used to think it was a remote possibility as well but really it DOES happen. ---
**Author:** ![Wysiwig](https://avatars.discourse-cdn.com/v4/letter/w/b2d939/32.png) [@Wysiwig](https://boards.straightdope.com/u/Wysiwig)\ **Post date:** [February 27, 2003, 11:27pm UTC](https://boards.straightdope.com/t/please-turn-off-cellular-phone-while-pumping-gas/157563/32 "2003-02-27T23:27:02Z")
At the Sainsburys Supermarket Filling Station on the A332 in Bracknell, England, my phone rang whilst I was in the pay office and they refused to serve me until I turned it off…It was a text message from Vodaphone offering me a holiday if I answered a question correctly! [Previous page](https://boards.straightdope.com/t/please-turn-off-cellular-phone-while-pumping-gas/157563.md?page=1)